ADE7854ACPZ_技术文档

Polyphase Multifunction Energy Metering IC

with Harmonic and Fundamental Information

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

harmonic) active, reactive (ADE7878, ADE7868, and

FEATURES

ADE7858), and apparent energy measurement and rms calcu-

Highly accurate; supports EN 50470-1, EN 50470-3,

IEC 62053-21, IEC 62053-22, and IEC 62053-23 standards

Compatible with 3-phase, 3- or 4-wire (delta or wye), and

other 3-phase services

Supplies total (fundamental and harmonic) active, reactive

(ADE7878, ADE7868, and ADE7858 only), and apparent

energy, and fundamental active/reactive energy (ADE7878

only) on each phase and on the overall system

Less than 0.1% error in active and reactive energy over a

dynamic range of 1000 to 1 at T_A= 25°C

Less than 0.2% error in active and reactive energy over a

dynamic range of 3000 to 1 at T_A= 25°C

Supports current transformer and di/dt current sensors

Dedicated ADC channel for neutral current input (ADE7868 and

ADE7878 only)

lations, as well as fundamental-only active and reactive energy

measurement (ADE7878) and rms calculations. A fixed function

digital signal processor (DSP) executes this signal processing.

The DSP program is stored in the internal ROM memory.

The ADE7854/ADE7858/ADE7868/ADE7878 are suitable for

measuring active, reactive, and apparent energy in various 3-phase

configurations, such as wye or delta services, with both three

and four wires. The ADE78xx devices provide system calibration

features for each phase, that is, rms offset correction, phase

calibration, and gain calibration. The CF1, CF2, and CF3 logic

outputs provide a wide choice of power information: total active,

reactive, and apparent powers, or the sum of the current rms

values, and fundamental active and reactive powers.

The ADE7854/ADE7858/ADE7868/ADE7878 contain wave-

form sample registers that allow access to all ADC outputs. The

devices also incorporate power quality measurements, such as

short duration low or high voltage detections, short duration

high current variations, line voltage period measurement, and

angles between phase voltages and currents. Two serial interfaces,

SPI and I²C, can be used to communicate with the ADE78xx. A

dedicated high speed interface, the high speed data capture

(HSDC) port, can be used in conjunction with I²C to provide

access to the ADC outputs and real-time power information.

The ADE7854/ADE7858/ADE7868/ADE7878 also have two

Less than 0.1% error in voltage and current rms over a

dynamic range of 1000 to 1 at T_A= 25°C

Supplies sampled waveform data on all three phases and on

neutral current

Selectable no load threshold levels for total and

fundamental active and reactive powers, as well as for

apparent powers

Low power battery mode monitors phase currents for

antitampering detection (ADE7868 and ADE7878 only)

Battery supply input for missing neutral operation

Phase angle measurements in both current and voltage

channels with a typical 0.3° error

IRQ0

IRQ1

interrupt request pins,

and , to indicate that an enabled

interrupt event has occurred. For the ADE7868/ADE7878, three

specially designed low power modes ensure the continuity of

energy accumulation when the ADE7868/ADE7878 is in a tam-

pering situation. See Table 1 for a quick reference chart listing

each part and its functions. The ADE78xx are available in the

40-lead LFCSP, Pb-free package.

Wide-supply voltage operation: 2.4 V to 3.7 V

Reference: 1.2 V (drift +5 ppm/°C typical) with external

overdrive capability

Single 3.3 V supply

40-lead lead frame chip scale package (LFCSP), Pb-free

Operating temperature: −40°C to +85°C

Flexible I²C, SPI, and HSDC serial interfaces

Table 1. Part Comparison

IRMS,

VRMS,

and

Tamper

Fundamental Detect and

APPLICATIONS

Energy metering systems

WATT and

di/dt VAR

Low Power

Modes

Part No.

WATT VAR VA

GENERAL DESCRIPTION

ADE7878 Yes

ADE7868 Yes

ADE7858 Yes

ADE7854 Yes

Yes

No

Yes

No

Yes

No

The ADE7854/ADE7858/ADE7868/ADE7878 are high accuracy,

3-phase electrical energy measurement ICs with serial interfaces

and three flexible pulse outputs. The ADE78xx devices incorporate

second-order sigma-delta (Σ-∆) analog-to-digital converters

(ADCs), a digital integrator, reference circuitry, and all of the

signal processing required to perform total (fundamental and

Rev. H

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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other

rights of third parties that may result from its use. Specifications subject to change without notice. No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Technical Support

www.analog.com

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

TABLE OF CONTENTS

Features .............................................................................................. 1

Power Quality Measurements................................................... 34

Phase Compensation ................................................................. 39

Reference Circuit........................................................................ 41

Digital Signal Processor............................................................. 42

Root Mean Square Measurement............................................. 43

Active Power Calculation.......................................................... 47

Applications....................................................................................... 1

General Description......................................................................... 1

Revision History ............................................................................... 3

Functional Block Diagrams............................................................. 5

Specifications..................................................................................... 9

Timing Characteristics .............................................................. 12

Absolute Maximum Ratings.......................................................... 15

Thermal Resistance .................................................................... 15

ESD Caution................................................................................ 15

Pin Configuration and Function Descriptions........................... 16

Typical Performance Characteristics ........................................... 18

Test Circuit ...................................................................................... 21

Terminology .................................................................................... 22

Power Management........................................................................ 23

PSM0—Normal Power Mode (All Parts)................................ 23

PSM1—Reduced Power Mode (ADE7868, ADE7878 Only)23

PSM2—Low Power Mode (ADE7868, ADE7878 Only)....... 23

PSM3—Sleep Mode (All Parts) ................................................ 24

Power-Up Procedure.................................................................. 26

Hardware Reset........................................................................... 27

Software Reset Functionality .................................................... 27

Theory of Operation ...................................................................... 28

Analog Inputs.............................................................................. 28

Analog-to-Digital Conversion.................................................. 28

Current Channel ADC............................................................... 29

di/dt Current Sensor and Digital Integrator .............................. 31

Voltage Channel ADC ............................................................... 32

Changing Phase Voltage Datapath........................................... 33

Reactive Power Calculation—ADE7858, ADE7868, ADE7878

Only.............................................................................................. 52

Apparent Power Calculation..................................................... 57

Waveform Sampling Mode ....................................................... 60

Energy-to-Frequency Conversion............................................ 60

No Load Condition.................................................................... 64

Checksum Register..................................................................... 65

Interrupts..................................................................................... 66

Serial Interfaces .......................................................................... 68

Quick Setup as Energy Meter ................................................... 75

Layout Guidelines....................................................................... 75

Crystal Circuit ............................................................................ 76

ADE7878 Evaluation Board...................................................... 76

Die Version.................................................................................. 76

Silicon Anomaly ............................................................................. 77

ADE7854/ADE7858/ADE7868/ADE7878 Functionality

Issues ............................................................................................ 77

Functionality Issues.................................................................... 77

Section 1. ADE7854/ADE7858/ADE7868/ADE7878

Functionality Issues.................................................................... 79

Registers List ................................................................................... 80

Outline Dimensions....................................................................... 98

Ordering Guide .......................................................................... 98

Rev. H | Page 2 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

REVISION HISTORY

4/14—Rev. G to Rev. H

Changes to Equation 20 and to Equation 21...............................45

Changes to Active Energy Calculation Section...........................46

Changes to Figure 62 and to following text and to Equation 25 ....47

Changes to Equation 32, Equation 34, and to Reactive

Changes to Power-Up Procedure Section....................................26

Changes to Crystal Circuit Section...............................................76

10/13—Rev. F to Rev. G

Power Gain Calibration Section....................................................50

Changes to Reactive Energy Calculation Section.......................51

Changes to Figure 66 ......................................................................52

Changes to Energy Accumulation Modes Sections and to

Caption for Figure 67......................................................................53

Changes to Equation 40 .................................................................54

Changes to Apparent Power Calculation Using VNOM Section...55

Changes to CF Outputs for Various Accumultation Modes

Section ..............................................................................................60

Changes to Sign of Sum-of-Phase Powers in the CFx

Datapath Section and to Equation 47...........................................61

Changes to Equation 48 .................................................................62

Changes to Checksum Register Section and to Table 23...........63

Changes to Figure 81 ......................................................................66

Changes to Figure 82 ......................................................................67

Changes to SPI-Compatible Interface Section............................68

Changes to HSDC Interface Section ............................................70

Changes to Figure 88 ......................................................................71

Changes to Figure 89, added Quick Setup as Energy Meter

Section, added Layout Guidelines, and added Figure 90;

Changes to Product Title and Features Section ............................1

Changes to Table 2 ............................................................................9

Deleted Junction Temperature; Table 6........................................15

Changes to NC and CLKIN Pin Descriptions.............................16

Replaced Typical Performance Characteristics Section.............18

Added Text to Test Circuit Section ...............................................21

Changes to Terminology Section ..................................................22

Changes to PSM2—Low Power Mode (ADE7868, ADE7878

Only) Section and Added Figure 25 .............................................24

Changes to Changing Phase Voltage Datapath Section and

Figure 42...........................................................................................33

Changes to Reference Circuit Section; Added Figure 56,

Figure 57, and Figure 58; Renumbered Sequentially..................41

Changes to Current RMS Compensation Section .........................44

Changes to Current Mean Absolute Value Calculation—

ADE7868 and ADE7878 Only and Figure 60..............................45

Changes to Voltage RMS Offset Compensation Section...............47

Changes to Line Cycle Active Energy Accumulation Mode

Section...............................................................................................51

Changes to Quick Setup as Energy Meter Section and

Renumbered Sequentially ..............................................................72

Added Figure 91 and Figure 92.....................................................73

Changes to Table 30 ........................................................................78

Changes to Table 33 ........................................................................79

Changes to Table 46 ........................................................................90

Figure 95...........................................................................................75

Changes to Figure 96 and Figure 97; Added Crystal Circuit

Section ..............................................................................................76

Changes to Address 0xE520 Description; Table 33 ....................84

Changes to Bit 11, Bit 12, Bit 13 Descriptions; Table 43 ............91

Updated Outline Dimensions........................................................99

4/11—Rev. D to Rev. E

Changes to Input Clock FrequencyParameter, Table 2 ..............10

Changes to Current RMS Offset Compensation Section ..........42

Changes to Voltage RMS Offset Compensation Section ...........44

Changes to Note 2, Table 30...........................................................77

Changes to Address 0xE707, Table 33..........................................80

Changes to Table 45 ........................................................................87

Changes to Table 46 ........................................................................88

Changes to Bit Location 7:3, Default Value, Table 54 ................92

10/12—Rev. E to Rev. F

Changes to Figure 1...........................................................................4

Changes to Figure 2...........................................................................5

Changes to Figure 3...........................................................................6

Changes to Figure 4...........................................................................7

Changes to Table 2 ............................................................................8

Changes to Figure 5.........................................................................11

Added Text under Table 6 ..............................................................14

Changes to Figure 9 and to Table 8...............................................15

Changes to Power-Up Procedure Section....................................24

Changes to Figure 31 and Figure 32 .............................................28

Changes to Figure 39 ......................................................................30

Changes to Voltage Waveform Gain Register Section................31

Changes to Figure 41 ......................................................................32

Changes to Phase Compensation Section....................................37

Changes to Digital Signal Processor Section...............................39

Changes to Equation 12..................................................................40

Changes to Current RMS Offset Compensation Section ..........42

Changes to Voltage Channel RMS Calculation Section.............43

Changes to Voltage RMS Offset Compensation Section and

to Figure 59 ......................................................................................44

2/11—Rev. C to Rev. D

Changes to Figure 1 ..........................................................................4

Changes to Figure 2 ..........................................................................5

Changes to Figure 3 ..........................................................................6

Changes to Figure 4 ..........................................................................7

Changes to Table 2 ............................................................................8

Changed SCLK Edge to HSCLK Edge, Table 5...........................13

Change to Current Channel HPF Section ...................................28

Change to di/dt Current Sensor and Digital Integrator Section ....30

Changes to Digital Signal Processor Section...............................39

Changes to Figure 59 ......................................................................44

Changes to Figure 62 ......................................................................47

Changes to Figure 65 ......................................................................49

Changes to Figure 66 ......................................................................52

Rev. H | Page 3 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Changes to Line Cycle Reactive Energy Accumulation Mode

Section and to Figure 67 ................................................................ 53

No Load Detection Based On Total Active, Reactive Powers

Section.............................................................................................. 61

Change to Equation 50................................................................... 63

Changes to the HSDC Interface Section ..................................... 70

Changes to Figure 87 and Figure 88............................................. 71

Changes to Figure 89...................................................................... 72

Changes to Table 30........................................................................ 77

Changes to Table 46........................................................................ 88

3/10—Rev. 0 to Rev. A

Added ADE7854, ADE7858, and ADE7878...................Universal

Reorganized Layout............................................................Universal

Added Table 1, Renumbered Sequentially .....................................1

Added Figure 1, Renumbered Sequentially ...................................3

Added Figure 2...................................................................................4

Added Figure 3...................................................................................5

Changes to Specifications Section...................................................7

Changes to Figure 9 and changes to Table 8 .............................. 14

Changes to Typical Performance Characteristics Section ........ 16

Changes to Figure 22...................................................................... 18

Changes to the Power Management Section .............................. 20

Changes to the Theory of Operation Section............................. 25

Changes to Figure 31 and Figure 32............................................. 27

Change to Equation 28 .................................................................. 47

Changes to Figure 83...................................................................... 66

Changes to Figure 86...................................................................... 68

Changes to the Registers List Section .......................................... 72

Changes to Ordering Guide.......................................................... 91

11/10—Rev. B to Rev. C

Change to Signal-to-Noise-and-Distortion Ratio, SINAD

Parameter, Table 1............................................................................. 9

Changes to Figure 18...................................................................... 18

Changes to Figure 22...................................................................... 19

Changes to Silicon Anomaly Section........................................... 72

Added Table 28 to Silicon Anomaly Section............................... 73

8/10—Rev. A to Rev. B

Changes to Figure 1.......................................................................... 4

Changes to Figure 2.......................................................................... 5

Changes to Figure 3.......................................................................... 6

Changes to Figure 4.......................................................................... 7

Change to Table 8 ........................................................................... 16

Changes to Power-Up Procedure Section ................................... 23

Changes to Equation 6 and Equation 7 ....................................... 33

Changes to Equation 17................................................................. 43

Changes to Active Power Offset Calibration Section ................ 45

Changes to Figure 63...................................................................... 46

Changes to Reactive Power Offset Calibration Section............. 49

Changes to Figure 82...................................................................... 65

Added Silicon Anomaly Section, Renumbered Tables

2/10—Revision 0: Initial Version

Sequentially ..................................................................................... 71

Rev. H | Page 4 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

FUNCTIONAL BLOCK DIAGRAMS

2 0 4

0

Figure 1. ADE7854 Functional Block Diagram

Rev. H | Page 5 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Figure 2. ADE7858 Functional Block Diagram

Rev. H | Page 6 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Figure 3. ADE7868 Functional Block Diagram

Rev. H | Page 7 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Figure 4. ADE7878 Functional Block Diagram

Rev. H | Page 8 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

SPECIFICATIONS

VDD = 3.3 V 10%, AGND = DGND = 0 V, on-chip reference, CLKIN = 16.384 MHz, T_MINto T_MAX= −40°C to +85°C, T_TYP= 25°C.

Table 2.

Parameter^{1, 2}

Min

Typ

Max

Unit

Test Conditions/Comments

ACCURACY

Active Energy Measurement

Active Energy Measurement Error

(per Phase)

Total Active Energy

0.1

0.2

0.1

0.2

0.1

%

Over a dynamic range of 1000 to 1, PGA = 1, 2, 4;

integrator off

Over a dynamic range of 3000 to 1, PGA = 1, 2, 4;

integrator off

Over a dynamic range of 500 to 1, PGA = 8, 16;

integrator on

Over a dynamic range of 1000 to 1, PGA = 1, 2, 4;

integrator off

Over a dynamic range of 3000 to 1, PGA = 1, 2, 4;

integrator off

Over a dynamic range of 500 to 1, PGA = 8, 16;

integrator on

Fundamental Active Energy

(ADE7878 Only)

AC Power Supply Rejection

Output Frequency Variation

DC Power Supply Rejection

VDD = 3.3 V + 120 mV rms/120 Hz/100 Hz, IPx =

VPx = 100 mV rms

0.01

%

VDD = 3.3 V 330 mV dc; IPx = VPx =

100 mV rms

Output Frequency Variation

Total Active Energy Measurement

Bandwidth

0.01

2

%

kHz

REACTIVE ENERGY MEASUREMENT

(ADE7858, ADE7868, AND ADE7878)

Reactive Energy Measurement Error

(per Phase)

Total Reactive Energy

0.1

0.2

0.1

0.2

0.1

%

Over a dynamic range of 1000 to 1, PGA = 1, 2, 4;

integrator off

Over a dynamic range of 3000 to 1, PGA = 1, 2, 4;

integrator off

Over a dynamic range of 500 to 1, PGA = 8, 16;

integrator on

Over a dynamic range of 1000 to 1, PGA = 1, 2, 4;

integrator off

Over a dynamic range of 3000 to 1, PGA = 1, 2, 4;

integrator off

Over a dynamic range of 500 to 1, PGA = 8, 16;

integrator on

Fundamental Reactive Energy

(ADE7878 Only)

AC Power Supply Rejection

Output Frequency Variation

DC Power Supply Rejection

VDD = 3.3 V + 120 mV rms/120 Hz/100 Hz, IPx =

VPx = 100 mV rms

0.01

%

VDD = 3.3 V 330 mV dc; IPx = VPx =

100 mV rms

Output Frequency Variation

Total Reactive Energy Measurement

Bandwidth

0.01

2

%

kHz

RMS MEASUREMENTS

I rms and V rms Measurement

Bandwidth

I rms and V rms Measurement Error

(PSM0 Mode)

2

kHz

%

0.1

Over a dynamic range of 1000 to 1, PGA = 1

Rev. H | Page 9 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Parameter^{1, 2}

Min

Typ

Max

Unit

Test Conditions/Comments

MEAN ABSOLUTE VALUE (MAV)

MEASUREMENT (ADE7868 AND

ADE7878)

I mav Measurement Bandwidth (PSM1

Mode)

I mav Measurement Error (PSM1 Mode)

ANALOG INPUTS

260

0.5

Hz

%

Over a dynamic range of 100 to 1, PGA = 1, 2, 4, 8

Maximum Signal Levels

500

mV peak PGA = 1, differential inputs between the

following pins: IAP and IAN, IBP and IBN, ICP

and ICN; single-ended inputs between the

following pins: VAP and VN, VBP and VN, VCP,

and VN

Input Impedance (DC)

IAP, IAN, IBP, IBN, ICP, ICN, VAP, VBP,

and VCP Pins

VN Pin

400

130

kΩ

ADC Offset

−24

4

mV

PGA = 1, uncalibrated error, see the Terminology

section

External 1.2 V reference

Gain Error

%

WAVEFORM SAMPLING

Current and Voltage Channels

Signal-to-Noise Ratio, SNR

Sampling CLKIN/2048, 16.384 MHz/2048 = 8 kSPS

See the Waveform Sampling Mode section

PGA = 1, fundamental frequency: 45 Hz to

65 Hz, see the Terminology section

PGA = 1; fundamental frequency: 45 Hz to

65 Hz, see the Terminology section

74

2

dB

Signal-to-Noise-and-Distortion Ratio,

SINAD

Bandwidth (−3 dB)

dB

kHz

TIME INTERVAL BETWEEN PHASES

Measurement Error

0.3

Degrees

Line frequency = 45 Hz to 65 Hz, HPF on

CF1, CF2, CF3 PULSE OUTPUTS

Maximum Output Frequency

Duty Cycle

8

50

kHz

%

WTHR = VARTHR = VATHR = PMAX = 33,516,139

If CF1, CF2, or CF3 frequency > 6.25 Hz and

CFDEN is even and > 1

(1 + 1/CFDEN)

× 50%

If CF1, CF2, or CF3 frequency > 6.25 Hz and

CFDEN is odd and > 1

Active Low Pulse Width

Jitter

80

0.04

ms

%

If CF1, CF2, or CF3 frequency < 6.25 Hz

For CF1, CF2, or CF3 frequency = 1 Hz and

nominal phase currents are larger than 10% of

full scale

REFERENCE INPUT

REF_IN/OUTInput Voltage Range

Input Capacitance

1.1

1.3

10

V

pF

Minimum = 1.2 V − 8%; maximum = 1.2 V + 8%

Nominal 1.2 V at the REF_IN/OUTpin at T_A= 25°C

ON-CHIP REFERENCE

PSM0 and PSM1 Modes

Temperature Coefficient

−50

5

+50

ppm/°C

MHz

Drift across the entire temperature range of −40°C

to +85°C is calculated with reference to 25°C;

see the Reference Circuit section for more details

CLKIN

All specifications CLKIN of 16.384 MHz. See the

Crystal Circuit section for more details.

Input Clock Frequency

16.22 16.384

2.0

16.55

LOGIC INPUTS—MOSI/SDA, SCLK/SCL, SS,

RESET, PM0, AND PM1

Input High Voltage, V_INH

Input Low Voltage, V_INL

Input Current, I_IN

V

µA

μA

pF

VDD = 3.3 V 10%

Input = 0 V, VDD = 3.3 V

Input = VDD = 3.3 V

0.8

−8.7

3

Input Capacitance, C_IN

10

Rev. H | Page 10 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Parameter^{1, 2}

Min

Typ

Max

Unit

Test Conditions/Comments

VDD = 3.3 V 10%

LOGIC OUTPUTS—IRQ0, IRQ1, MISO/HSD

Output High Voltage, V_OH

2.4

V

VDD = 3.3 V 10%

I_SOURCE

Output Low Voltage, V_OL

I_SINK

800

0.4

2

µA

V

mA

VDD = 3.3 V 10%

CF1, CF2, CF3/HSCLK

Output High Voltage, V_OH

I_SOURCE

Output Low Voltage, V_OL

I_SINK

2.4

V

µA

V

VDD = 3.3 V 10%

500

0.4

2

VDD = 3.3 V 10%

mA

POWER SUPPLY

PSM0 Mode

VDD Pin

For specified performance

Minimum = 3.3 V − 10%; maximum = 3.3 V + 10%

2.97

2.4

3.63

27.2

V

mA

I_DD

24.4

PSM1 and PSM2 Modes (ADE7868 and

ADE7878)

VDD Pin

I_DD

3.7

V

PSM1 Mode

PSM2 Mode

PSM3 Mode

VDD Pin

6.0

0.2

mA

2.4

3.7

V

I_DDin PSM3 Mode

1.7

μA

¹See the Typical Performance Characteristics section.

²See the Terminology section for a definition of the parameters.

Rev. H | Page 11 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

TIMING CHARACTERISTICS

VDD = 3.3 V 10%, AGND = DGND = 0 V, on-chip reference, CLKIN = 16.384 MHz, T_MINto T_MAX= −40°C to +85°C. Note that dual

function pin names are referenced by the relevant function only within the timing tables and diagrams; see the Pin Configuration and

Function Descriptions section for full pin mnemonics and descriptions.

Table 3. I²C-Compatible Interface Timing Parameter

Standard Mode

Fast Mode

Parameter

Symbol

f_SCL

t_HD;STA

t_LOW

t_HIGH

t_SU;STA

t_HD;DAT

t_SU;DAT

t_R

Min

Max

Min

Max

Unit

kHz

μs

µs

ns

µs

ns

SCL Clock Frequency

Hold Time (Repeated) Start Condition

Low Period of SCL Clock

High Period of SCL Clock

Set-Up Time for Repeated Start Condition

Data Hold Time

0

100

0

400

4.0

4.7

4.0

4.7

0

0.6

1.3

0.6

0

100

20

0.6

1.3

3.45

0.9

Data Setup Time

250

Rise Time of Both SDA and SCL Signals

Fall Time of Both SDA and SCL Signals

Setup Time for Stop Condition

Bus Free Time Between a Stop and Start Condition

Pulse Width of Suppressed Spikes

1000

300

t_F

t_SU;STO

t_BUF

4.0

4.7

N/A¹

t_SP

50

¹N/A means not applicable.

SDA

t_BUF

t_SU;DAT

t_R

t_HD;STA

t_F

t_SP

t_R

t_F

t_LOW

SCLK

t_HD;STA

t_SU;STO

t_HD;DAT

t_SU;STA

t_HIGH

START

CONDITION

REPEATED START

CONDITION

STOP

START

CONDITION CONDITION

Figure 5. I²C-Compatible Interface Timing

Rev. H | Page 12 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Table 4. SPI Interface Timing Parameters

Parameter

Symbol

Min

50

Max

Unit

ns

μs

ns

SS to SCLK Edge

t_SS

SCLK Period

SCLK Low Pulse Width

0.4

175

4000¹

t_SL

t_SH

SCLK High Pulse Width

Data Output Valid After SCLK Edge

Data Input Setup Time Before SCLK Edge

Data Input Hold Time After SCLK Edge

Data Output Fall Time

Data Output Rise Time

SCLK Rise Time

SCLK Fall Time

MISO Disable After SS Rising Edge

SS High After SCLK Edge

t_DAV

t_DSU

t_DHD

t_DF

t_DR

t_SR

t_SF

t_DIS

t_SFS

100

5

20

200

0

¹Guaranteed by design.

SS

t_SS

t_SFS

SCLK

t_SL

t_SH

t_SF

t_SR

t_DAV

t_DIS

MSB

INTERMEDIATE BITS

LSB

MISO

t_DF

t_DR

INTERMEDIATE BITS

MSB IN

LSB IN

MOSI

t_DSU

t_DHD

Figure 6. SPI Interface Timing

Rev. H | Page 13 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Table 5. HSDC Interface Timing Parameter

Parameter

HSA to HSCLK Edge

Symbol

Min

0

125

50

Max

Unit

ns

t_SS

HSCLK Period

HSCLK Low Pulse Width

HSCLK High Pulse Width

Data Output Valid After HSCLK Edge

Data Output Fall Time

Data Output Rise Time

HSCLK Rise Time

HSCLK Fall Time

HSD Disable After HSA Rising Edge

HSA High After HSCLK Edge

t_SL

t_SH

t_DAV

t_DF

t_DR

t_SR

t_SF

t_DIS

t_SFS

50

40

20

10

5

0

HSA

t_SS

t_SFS

HSCLK

t_SL

t_SH

t_SF

t_SR

t_DAV

t_DIS

MSB

INTERMEDIATE BITS

t_DF

LSB

HSD

t_DR

Figure 7. HSDC Interface Timing

2mA

I

OL

TO OUTPUT

1.6V

C

L

50pF

800µA

I

OH

Figure 8. Load Circuit for Timing Specifications

Rev. H | Page 14 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

ABSOLUTE MAXIMUM RATINGS

T_A= 25°C, unless otherwise noted.

THERMAL RESISTANCE

θ_JAis specified equal to 29.3°C/W; θ_JCis specified equal to

1.8°C/W.

Table 6.

Parameter

Rating

VDD to AGND

VDD to DGND

Analog Input Voltage to AGND, I A P,

IAN, IBP, IBN, ICP, ICN, VAP, VBP, VCP,

VN

−0.3 V to +3.7 V

−2 V to +2 V

Table 7. Thermal Resistance

Package Type

θ_JA

θ_JC

Unit

40-Lead LFCSP

29.3

1.8

°C/W

Analog Input Voltage to INP and INN

Reference Input Voltage to AGND

Digital Input Voltage to DGND

Digital Output Voltage to DGND

Operating Temperature

−2 V to +2 V

ESD CAUTION

−0.3 V to VDD + 0.3 V

Industrial Range

Storage Temperature Range

Lead Temperature (Soldering, 10 sec)

−40°C to +85°C

−65°C to +150°C

300°C

Note that, regarding the temperature profile used in soldering

RoHS compliant parts, Analog Devices advises that reflow

profiles should conform to J-STD 20 from JEDEC. Refer to

www.jedec.org for the latest revision.

Stresses above those listed under Absolute Maximum Ratings

may cause permanent damage to the device. This is a stress

rating only; functional operation of the device at these or any

other conditions above those listed in the operational sections

of this specification is not implied. Exposure to absolute

maximum rating conditions for extended periods may affect

device reliability.

Rev. H | Page 15 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

NC

PM0

1

2

3

4

5

6

7

8

9

30

29

28

NC

IRQ0

PM1

CLKOUT

RESET

DVDD

DGND

IAP

IAN

IBP

27 CLKIN

26 VDD

25 AGND

24 AVDD

23 VAP

22 VBP

NC

21

ADE78xx

TOP VIEW

(Not to Scale)

NC 10

NOTES

1. NC = NO CONNECT.

2. CREATE A SIMILAR PAD ON THE PCB UNDER THE

EXPOSED PAD. SOLDER THE EXPOSED PAD TO

THE PAD ON THE PCB TO CONFER MECHANICAL

STRENGTH TO THE PACKAGE. CONNECT THE

PADS TO AGND AND DGND.

Figure 9. Pin Configuration

Table 8. Pin Function Descriptions

Pin No.

Mnemonic

Description

1, 10, 11, 20,

21, 30, 31, 40

NC

No Connect. These pins are not connected internally. It is recommended to ground these pins.

2

3

4

5

PM0

Power Mode Pin 0. This pin, combined with PM1, defines the power mode of the

ADE7854/ADE7858/ADE7868/ADE7878, as described in Table 9.

Power Mode Pin 1. This pin defines the power mode of the ADE7854/ADE7858/ADE7868/ADE7878

when combined with PM0, as described in Table 9.

Reset Input, Active Low. In PSM0 mode, this pin should stay low for at least 10 µs to trigger a

hardware reset.

2.5 V output of the digital low dropout regulator (LDO). Decouple this pin with a 4.7 µF capacitor in

parallel with a ceramic 220 nF capacitor. Do not connect external active circuitry to this pin.

PM1

RESET

DVDD

6

DGND

Ground Reference. This pin provides the ground reference for the digital circuitry.

7, 8

IAP, IAN

Analog Inputs for Current Channel A. This channel is used with the current transducers and is

referenced in this document as Current Channel A. These inputs are fully differential voltage inputs

with a maximum differential level of 0.5 V. This channel also has an internal PGA equal to the ones

on Channel B and Channel C.

9, 12

IBP, IBN

ICP, ICN

INP, INN

Analog Inputs for Current Channel B. This channel is used with the current transducers and is

referenced in this document as Current Channel B. These inputs are fully differential voltage inputs

with a maximum differential level of 0.5 V. This channel also has an internal PGA equal to the ones

on Channel C and Channel A.

Analog Inputs for Current Channel C. This channel is used with the current transducers and is

referenced in this document as Current Channel C. These inputs are fully differential voltage inputs

with a maximum differential level of 0.5 V. This channel also has an internal PGA equal to the ones

on Channel A and Channel B.

Analog Inputs for Neutral Current Channel N. This channel is used with the current transducers and

is referenced in this document as Current Channel N. These inputs are fully differential voltage

inputs with a maximum differential level of 0.5 V. This channel also has an internal PGA, different

from the ones found on the A, B, and C channels. The neutral current channel is available in the

ADE7878 and ADE7868. In the ADE7858 and ADE7854, connect these pins to AGND.

13, 14

15, 16

17

REF_IN/OUT

This pin provides access to the on-chip voltage reference. The on-chip reference has a nominal

value of 1.2 V. An external reference source with 1.2 V 8% can also be connected at this pin. In

either case, decouple this pin to AGND with a 4.7 µF capacitor in parallel with a ceramic 100 nF

capacitor. After reset, the on-chip reference is enabled.

Rev. H | Page 16 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Pin No.

Mnemonic

Description

18, 19, 22, 23

VN, VCP, VBP, VAP

Analog Inputs for the Voltage Channel. This channel is used with the voltage transducer and is

referenced as the voltage channel in this document. These inputs are single-ended voltage inputs

with a maximum signal level of 0.5 V with respect to VN for specified operation. This channel also

has an internal PGA.

24

25

AVDD

AGND

2.5 V output of the analog low dropout regulator (LDO). Decouple this pin with a 4.7 µF capacitor in

parallel with a ceramic 220 nF capacitor. Do not connect external active circuitry to this pin.

Ground Reference. This pin provides the ground reference for the analog circuitry. Tie this pin to the

analog ground plane or to the quietest ground reference in the system. Use this quiet ground

reference for all analog circuitry, for example, antialiasing filters, current, and voltage transducers.

26

VDD

Supply Voltage. This pin provides the supply voltage. In PSM0 (normal power mode), maintain the

supply voltage at 3.3 V 10% for specified operation. In PSM1 (reduced power mode), PSM2 (low

power mode), and PSM3 (sleep mode), when the ADE7868/ADE7878 is supplied from a battery,

maintain the supply voltage between 2.4 V and 3.7 V. Decouple this pin to AGND with a 10 µF

capacitor in parallel with a ceramic 100 nF capacitor. The only modes available on the ADE7858 and

ADE7854 are the PSM0 and PSM3 power modes.

27

CLKIN

Master Clock. An external clock can be provided at this logic input. Alternatively, a crystal can be

connected across CLKIN and CLKOUT to provide a clock source for the ADE7854/ADE7858/

ADE7868/ADE7878. The clock frequency for specified operation is 16.384 MHz. See the Crystal

Circuit section for details on choosing a suitable crystal.

28

CLKOUT

A crystal can be connected across this pin and CLKIN (as previously described with Pin 27 in this

table) to provide a clock source for the ADE7854/ADE7858/ADE7868/ADE7878.

29, 32

33, 34, 35

IRQ0, IRQ1

Interrupt Request Outputs. These are active low logic outputs. See the Interrupts section for a

detailed presentation of the events that can trigger interrupts.

Calibration Frequency (CF) Logic Outputs. These outputs provide power information based on the

CF1SEL[2:0], CF2SEL[2:0], and CF3SEL[2:0] bits in the CFMODE register. These outputs are used for

operational and calibration purposes. The full-scale output frequency can be scaled by writing to the

CF1DEN, CF2DEN, and CF3DEN registers, respectively (see the Energy-to-Frequency Conversion

section). CF3 is multiplexed with the serial clock output of the HSDC port.

CF1, CF2,

CF3/HSCLK

36

SCLK/SCL

Serial Clock Input for SPI Port/Serial Clock Input for I²C Port. All serial data transfers are synchronized

to this clock (see the Serial Interfaces section). This pin has a Schmidt trigger input for use with a

clock source that has a slow edge transition time, for example, opto-isolator outputs.

37

38

39

EP

MISO/HSD

MOSI/SDA

SS/HSA

Data Out for SPI Port/Data Out for HSDC Port.

Data In for SPI Port/Data Out for I²C Port.

Slave Select for SPI Port/HSDC Port Active.

Exposed Pad

Create a similar pad on the PCB under the exposed pad. Solder the exposed pad to the pad on the

PCB to confer mechanical strength to the package. Connect the pads to AGND and DGND.

Rev. H | Page 17 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

TYPICAL PERFORMANCE CHARACTERISTICS

1.5

1.2

+85°C

+25°C

–40°C

VDD = 3.3V

+85°C

+25°C

–40°C

VDD = 3.3V

1.2

0.9

0.6

0.3

0

–0.3

–0.6

–0.9

–1.2

–1.5

–0.3

–0.6

–0.9

–1.2

–1.5

0.01

0.1

1

10

100

0.01

0.1

1

10

100

PERCENTAGE OF FULL-SCALE CURRENT (%)

Figure 13. Total Active Energy Error As Percentage of Reading (Gain = +16,

Power Factor = 1) over Temperature with Internal Reference and Integrator On

Figure 10. Total Active Energy Error As Percentage of Reading (Gain = +1,

Power Factor = 1) over Temperature with Internal Reference and Integrator Off

1.5

0.15

+85°C

+25°C

–40°C

VDD = 3.3V

PF = +0.5

PF = –0.5

PF = +1.0

1.2

0.9

0.10

0.6

0.05

0

0.3

0

–0.3

–0.6

–0.9

–1.2

–1.5

–0.05

–0.10

–0.15

0.01

0.1

1

10

100

45

50

55

60

65

PERCENTAGE OF FULL-SCALE CURRENT (%)

LINE FREQUENCY (Hz)

Figure 14. Total Reactive Energy Error As Percentage of Reading (Gain = +1,

Power Factor = 0) over Temperature with Internal Reference and Integrator Off

Figure 11. Total Active Energy Error As Percentage of Reading (Gain = +1)

over Frequency with Internal Reference and Integrator Off

0.15

1.5

PF = +0.866

PF = –0.866

PF = 0

3.63V

3.30V

2.97V

T = 25°C

A

1.2

0.9

0.10

0.6

0.05

0

0.3

0

–0.3

–0.6

–0.9

–1.2

–1.5

–0.05

–0.10

–0.15

45

50

55

60

65

0.01

0.1

1

10

100

LINE FREQUENCY (Hz)

PERCENTAGE OF FULL-SCALE CURRENT (%)

Figure 12. Total Active Energy Error As Percentage of Reading (Gain = +1,

Power Factor = 1) over Power Supply with Internal Reference and Integrator Off

Figure 15. Total Reactive Energy Error As Percentage of Reading (Gain = +1)

over Frequency with Internal Reference and Integrator Off

Rev. H | Page 18 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

1.5

3.63V

3.30V

2.97V

T

= 25°C

+85°C

+25°C

–40°C

VDD = 3.3V

A

1.2

0.9

1.2

0.9

0.6

0.3

0

–0.3

–0.6

–0.9

–1.2

–1.5

–0.3

–0.6

–0.9

–1.2

–1.5

0.01

0.1

1

10

100

0.01

0.1

1

10

100

PERCENTAGE OF FULL-SCALE CURRENT (%)

Figure 16. Total Reactive Energy Error As Percentage of Reading (Gain = +1,

Power Factor = 0) over Power Supply with Internal Reference and Integrator Off

Figure 19. Fundamental Active Energy Error As Percentage of Reading

(Gain = +16) over Temperature with Internal Reference and Integrator On

1.5

0.15

+85°C

+25°C

–40°C

VDD = 3.3V

PF = +0.866

PF = –0.866

PF = 0

1.2

0.9

0.10

0.6

0.05

0

0.3

0

–0.3

–0.6

–0.9

–1.2

–1.5

–0.05

–0.10

–0.15

0.01

0.1

1

10

100

45

50

55

60

65

PERCENTAGE OF FULL-SCALE CURRENT (%)

LINE FREQUENCY (Hz)

Figure 17. Total Reactive Energy Error As Percentage of Reading (Gain = +16,

Power Factor = 0) over Temperature with Internal Reference and Integrator On

Figure 20. Fundamental Reactive Energy Error As Percentage of Reading

(Gain = +1) over Frequency with Internal Reference and Integrator Off

0.15

1.5

PF = +0.5

PF = –0.5

PF = +1.0

+85°C

+25°C

–40°C

VDD = 3.3V

1.2

0.9

0.10

0.6

0.05

0

0.3

0

–0.3

–0.6

–0.9

–1.2

–1.5

–0.05

–0.10

–0.15

45

50

55

60

65

0.01

0.1

1

10

100

LINE FREQUENCY (Hz)

PERCENTAGE OF FULL-SCALE CURRENT (%)

Figure 21. Fundamental Reactive Energy Error As Percentage of Reading

(Gain = +16) over Temperature with Internal Reference and Integrator On

Figure 18. Fundamental Active Energy Error As Percentage of Reading

(Gain = +1) over Frequency with Internal Reference and Integrator Off

Rev. H | Page 19 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

1.5

+85°C

+25°C

–40°C

VDD = 3.3V

1.2

0.9

0.6

0.3

0

–0.3

–0.6

–0.9

–1.2

–1.5

0.01

0.1

1

10

100

PERCENTAGE OF FULL-SCALE CURRENT (%)

Figure 22. IRMS Error as Percentage of Reading (Gain = +1, Power Factor = 1)

over Temperature with Internal Reference and Integrator Off

Rev. H | Page 20 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

TEST CIRCUIT

Note that in Figure 23, the PM1 and PM0 pins are pulled up internally to 3.3 V. Select the mode of operation by using a microcontroller to

programmatically change the pin values.

3.3V

+

0.1µF

10µF

+

0.22µF

4.7µF

24

26

5

3.3V

2

3

PM0

39

38

SS/HSA

MOSI/SDA

PM1

RESET

IAP

10kΩ

1µF

1kΩ

4

MISO/HSD 37

7

22nF

3.3V

36

SCLK/SCL

8

IAN

35

34

33

32

29

17

CF3/HSCLK

CF2

10kΩ

9

IBP

SAME AS

IAP, IAN

ADE78xx

12

13

14

18

19

22

23

IBN

SAME AS

CF2

1.5kΩ

CF1

ICP

SAME AS

IAP, IAN

IRQ1

IRQ0

ICN

22nF

1kΩ

VN

REF

IN/OUT

+

VCP

VBP

VAP

CL

2

0.1µF

4.7µF

22nF

28

1kΩ

CLKOUT

SAME AS

VCP

SAME AS

VCP

16.384MHz

5MΩ

27

CLKIN

CL

1

6

25

Figure 23. Test Circuit

Rev. H | Page 21 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

TERMINOLOGY

Measurement Error

Gain Error

The error associated with the energy measurement made by the

ADE7854/ADE7858/ADE7868/ADE7878 is defined by

The gain error in the ADCs of the ADE7854/ADE7858/

ADE7868/ADE7878 is defined as the difference between the

measured ADC output code (minus the offset) and the ideal

output code (see the Current Channel ADC section and the

Voltage Channel ADC section). The difference is expressed as a

percentage of the ideal code.

Measurement Error =

Energy Registered by ADE78xx −TrueEnergy

×100% (1)

TrueEnergy

Power Supply Rejection (PSR)

CF Jitter

This quantifies the ADE7854/ADE7858/ADE7868/ADE7878

measurement error as a percentage of reading when the power

supplies are varied. For the ac PSR measurement, a reading at

nominal supplies (3.3 V) is taken. A second reading is obtained

with the same input signal levels when an ac signal (120 mV rms

at twice the fundamental frequency) is introduced onto the

supplies. Any error introduced by this ac signal is expressed as a

percentage of reading—see the Measurement Error definition.

The period of pulses at one of the CF1, CF2, or CF3 pins is

continuously measured. The maximum, minimum, and average

values of four consecutive pulses are computed as follows:

Maximum = max(Period₀, Period₁, Period₂, Period₃)

Minimum = min(Period₀, Period₁, Period₂, Period₃)

Period₀+ Period₁+ Period₂+ Period₃

Average =

4

For the dc PSR measurement, a reading at nominal supplies

(3.3 V) is taken. A second reading is obtained with the same

input signal levels when the power supplies are varied 10%.

Any error introduced is expressed as a percentage of the

reading.

The CF jitter is then computed as

Maximum− Minimum

CF_JITTER

=

×100%

(2)

Average

Signal-to-Noise Ratio (SNR)

ADC Offset Error

SNR is the ratio of the rms value of the actual input signal to

the rms sum of all other spectral components below 2 kHz,

excluding harmonics and dc. The input signal contains only

the fundamental component. The spectral components are

calculated over a 2 sec window. The value for SNR is expressed

in decibels.

This refers to the dc offset associated with the analog inputs to

the ADCs. It means that with the analog inputs connected to

AGND, the ADCs still see a dc analog input signal. The magni-

tude of the offset depends on the gain and input range selection

However, the HPF removes the offset from the current and voltage

channels and the power calculation remains unaffected by this

offset.

Signal-to-(Noise and Distortion) Ratio (SINAD)

SINAD is the ratio of the rms value of the actual input signal

to the rms sum of all other spectral components below 2 kHz,

including harmonics but excluding dc. The input signal

contains only the fundamental component. The spectral

components are calculated over a 2 sec window. The value

for SINAD is expressed in decibels.

Rev. H | Page 22 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

POWER MANAGEMENT

The ADE7868/ADE7878 have four modes of operation, deter-

mined by the state of the PM0 and PM1 pins (see Table 9). The

ADE7854/ADE7858 have two modes of operation. These pins

provide complete control of the ADE7854/ADE7858/ADE7868/

ADE7878 operation and can easily be connected to an external

microprocessor I/O. The PM0 and PM1 pins have internal pull-

up resistors. See Table 11 and Table 12 for a list of actions that are

recommended before and after setting a new power mode.

In summary, in this mode, it is not recommended to access any

register other than AIMAV, BIMAV, and CIMAV. The circuit

that measures these estimates of rms values is also active during

PSM0; therefore, its calibration can be completed in either PSM0

mode or in PSM1 mode. Note that the ADE7868 and ADE7878

do not provide any register to store or process the corrections

resulting from the calibration process. The external microprocessor

stores the gain values in connection with these measurements

and uses them during PSM1 (see the Current Mean Absolute

Value Calculation—ADE7868 and ADE7878 Only section for

more details on the xIMAV registers).

Table 9. Power Supply Modes

Power Supply Modes

PM1

PM0

PSM0, Normal Power Mode

PSM1, Reduced Power Mode¹

PSM2, Low Power Mode¹

PSM3, Sleep Mode

0

1

0

1

The 20-bit mean absolute value measurements done in PSM1,

although available also in PSM0, are different from the rms

measurements of phase currents and voltages executed only in

PSM0 and stored in the xIRMS and xVRMS 24-bit registers.

See the Current Mean Absolute Value Calculation—ADE7868

and ADE7878 Only section for details.

¹Available in the ADE7868 and ADE7878.

PSM0—NORMAL POWER MODE (ALL PARTS)

In PSM0 mode, the ADE7854/ADE7858/ADE7868/ADE7878

are fully functional. The PM0 pin is set to high and the PM1 pin

is set to low for the ADE78xx to enter this mode. If the ADE78xx

is in one of PSM1, PSM2, or PSM3 modes and is switched into

PSM0 mode, then all control registers take the default values with

the exception of the threshold register, LPOILVL, which is used

in PSM2 mode, and the CONFIG2 register, both of which

maintain their values.

If the ADE7868/ADE7878 is set in PSM1 mode while still in the

PSM0 mode, the ADE7868/ADE7878 immediately begin the

mean absolute value calculations without any delay. The xIMAV

registers are accessible at any time; however, if the ADE7878 or

ADE7868 is set in PSM1 mode while still in PSM2 or PSM3

modes, the ADE7868/ADE7878 signal the start of the mean

IRQ1

absolute value computations by triggering the

pin low.

The xIMAV registers can be accessed only after this moment.

The ADE7854/ADE7858/ADE7868/ADE7878 signal the end of

PSM2—LOW POWER MODE (ADE7868, ADE7878

ONLY)

IRQ1

the transition period by triggering the

interrupt pin low and

setting Bit 15 (RSTDONE) in the STATUS1 register to 1. This bit is

0 during the transition period and becomes 1 when the transition is

The low power mode, PSM2, is available on the ADE7868 and

ADE7878 only. In this mode, the ADE7868/ADE7878 compare

all phase currents against a threshold for a period of 0.02 ×

(LPLINE[4:0] + 1) seconds, independent of the line frequency.

LPLINE[4:0] are Bits[7:3] of the LPOILVL register (see Table 10).

IRQ1

finished. The status bit is cleared and the

pin is set back to

high by writing to the STATUS1 register with the corresponding

bit set to 1. Bit 15 (RSTDONE) in the interrupt mask register

IRQ1

does not have any functionality attached even if the

pin goes

Table 10. LPOILVL Register

low when Bit 15 (RSTDONE) in the STATUS1 register is set to 1.

This makes the RSTDONE interrupt unmaskable.

Bit

Mnemonic Default Description

[2:0] LPOIL[2:0]

111

Threshold is put at a value

corresponding to full scale

multiplied by LPOIL/8.

PSM1—REDUCED POWER MODE (ADE7868,

ADE7878 ONLY)

The reduced power mode, PSM1, is available on the ADE7868

and ADE7878 only. In this mode, the ADE7868/ADE7878

measure the mean absolute values (mav) of the 3-phase currents

and store the results in the AIMAV, BIMAV, and CIMAV 20-bit

registers. This mode is useful in missing neutral cases in which

the voltage supply of the ADE7868 or ADE7878 is provided by an

external battery. The serial ports, I²C or SPI, are enabled in this

mode; the active port can be used to read the AIMAV, BIMAV,

and CIMAV registers. It is not recommended to read any of the

other registers because their values are not guaranteed in this

mode. Similarly, a write operation is not taken into account by

the ADE7868/ADE7878 in this mode.

[7:3] LPLINE[4:0] 00000

The measurement period is

(LPLINE[4:0] + 1)/50 sec.

Rev. H | Page 23 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

The threshold is derived from Bits[2:0] (LPOIL[2:0]) of the

LPOILVL register as LPOIL[2:0]/8 of full scale. Every time

one phase current becomes greater than the threshold, a

counter is incremented. If every phase counter remains below

LPLINE[4:0] + 1 at the end of the measurement period, then

The PSM2 level threshold comparison works based on a peak

detection methodology. The peak detect circuit makes the

comparison based on the positive terminal current channel

input, I_AP, I_BP, and I_CP(see Figure 25). In case of differential

inputs being applied to the current channels, Figure 25 shows

the differential antiphase signals at each of the current input

terminals, I_xPand I_xN, and the net differential current, I_xP– I_xN.

The I²C or SPI port is not functional during this mode. The PSM2

mode reduces the power consumption required to monitor the

currents when there is no voltage input and the voltage supply

of the ADE7868/ADE7878 is provided by an external battery. If

IRQ0

the

greater or equal to LPLINE[4:0] + 1 at the end of the measure-

IRQ1

pin is triggered low. If a single phase counter becomes

ment period, the

pin is triggered low. Figure 24 illustrates

how the ADE7868/ADE7878 behave in PSM2 mode when

LPLINE[4:0] = 2 and LPOIL[2:0] = 3. The test period is three

50 Hz cycles (60 ms), and the Phase A current rises above the

LPOIL[2:0] threshold three times. At the end of the test period,

IRQ0

the

pin is triggered low at the end of a measurement period,

IRQ1

the

pin is triggered low.

this signifies all phase currents stayed below threshold and,

therefore, there is no current flowing through the system.

At this point, the external microprocessor sets the ADE7868/

LPLINE[4:0] = 2

LPOIL[2:0]

THRESHOLD

IRQ1

ADE7878 into Sleep Mode PSM3. If the

pin is triggered

low at the end of the measurement period, this signifies that at

least one current input is above the defined threshold and

current is flowing through the system, although no voltage is

present at the ADE7868/ADE7878 pins. This situation is often

called missing neutral and is considered a tampering situation,

at which point the external microprocessor sets the ADE7868/

ADE7878into PSM1 mode, measures the mean absolute values

of phase currents, and integrates the energy based on their values

and the nominal voltage.

IA CURRENT

PHASE

COUNTER = 1

PHASE

COUNTER = 2

PHASE

COUNTER = 3

It is recommended to use the ADE7868/ADE7878 in PSM2

mode when Bits[2:0] (PGA1[2:0]) of the gain register are equal

to 1 or 2. These bits represent the gain in the current channel

datapath. It is not recommended to use the ADE7868/ADE7878

in PSM2 mode when the PGA1[2:0] bits are equal to 4, 8, or 16.

IRQ1

(50 Hz Systems)

Figure 24. PSM2 Mode Triggering

Pin for LPLINE[4:0] = 2

+V p-p/2

+V p-p

PSM3—SLEEP MODE (ALL PARTS)

I

xP

The sleep mode is available on all parts (ADE7854, ADE7858,

ADE7868, and ADE7878). In this mode, the ADE78xx has most

of its internal circuits turned off and the current consumption is

at its lowest level. The I²C, HSDC, and SPI ports are not func-

I

– I

xN

xP

–V p-p/2

+V p-p/2

I

xN

RESET

tional during this mode, and the

SS

, SCLK/SCL, MOSI/SDA,

–V p-p

–V p-p/2

and /HSA pins should be set high.

(a)

I

xP

TAMPER

INDICATION

PEAK DETECT CIRCUIT

V

REF

(b)

Figure 25. PSM2 Low Power Mode Peak Detection

Rev. H | Page 24 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Table 11. Power Modes and Related Characteristics

LPOILVL,

CONFIG2

Power Mode

All Registers¹

I²C/SPI

Functionality

PSM0

State After Hardware Reset

Set to default

Not available

Set to default

Unchanged

I²C enabled

All circuits are active and DSP

is in idle mode.

State After Software Reset

Active serial port is unchanged if lock-in

procedure has been previously executed

All circuits are active and DSP

is in idle mode.

PSM1—ADE7878, ADE7868 Only

Values set

Enabled

Current mean absolute values

are computed and the results

are stored in the AIMAV,

BIMAV, and CIMAV registers.

The I²C or SPI serial port is

enabled with limited

during PSM0

unchanged

functionality.

PSM2—ADE7878, ADE7868 Only

Not available

Values set

during PSM0

unchanged

Disabled

Compares phase currents

against the threshold set in

IRQ0 IRQ1

LPOILVL. Triggers

or

pins accordingly. The serial

ports are not available.

PSM3

Values set

during PSM0

unchanged

Internal circuits shut down

and the serial ports are not

available.

¹Setting for all registers except the LPOILVL and CONFIG2 registers.

Table 12. Recommended Actions When Changing Power Modes

Recommended Actions

Next Power Mode

Initial Power

Mode

Before Setting Next

Power Mode

PSM0

PSM1

PSM2

Wait until the

IRQ1

PSM3

PSM0

Stop DSP by setting the run

register = 0x0000.

Current mean absolute

values (mav) computed

immediately.

IRQ0

pin is triggered

No action

necessary.

or

accordingly.

Disable HSDC by clearing Bit 6

(HSDEN) to 0 in the CONFIG

register.

xIMAV registers can be

accessed immediately.

Mask interrupts by setting

MASK0 = 0x0 and

MASK1 = 0x0.

Erase interrupt status flags in

the STATUS0 and STATUS1

registers.

PSM1—

ADE7878,

ADE7868 Only

No action necessary.

IRQ1

IRQ0

or

pin is triggered

No action

necessary.

Wait until the

triggered low.

pin is

Wait until the

IRQ1

accordingly.

Poll the STATUS1 register

until Bit 15 (RSTDONE) is

set to 1.

PSM2—

ADE7878,

ADE7868 Only

No action necessary.

IRQ1

No action

necessary.

Wait until the

triggered low.

pin is

Wait until the

triggered low.

Poll the STATUS1 register

until Bit 15 (RSTDONE) is

set to 1.

Current mean absolute

values compute at this

moment.

xIMAV registers may be

accessed from this

moment.

PSM3

No action necessary.

IRQ1

IRQ0

Wait until the or

Wait until the

triggered low.

pin is

Wait until the

triggered low.

pin is

IRQ1

pin is triggered

accordingly.

Poll the STATUS1 register

until Bit 15 (RSTDONE) is

set to 1.

Current mav circuit begins

computations at this time.

xIMAV registers can be

accessed from this

moment.

Rev. H | Page 25 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

POWER-UP PROCEDURE

3.3V – 10%

2.0V ± 10%

ADE78xx

PSM0 READY

0V

~26ms

~40ms

MICROPROCESSOR

MAKES THE

MICROPROCESSOR

POR TIMER

CHOICE BETWEEN

I C AND SPI

ADE78xx

FULLY

POWERED UP

RSTDONE

INTERRUPT

TRIGGERED

2

SETS PM1 PIN TO 0;

TURNED ON

APPLY VDD TO CHIP

Figure 26. Power-Up Procedure

The ADE7854/ADE7858/ADE7868/ADE7878 contain an on-

chip power supply monitor that supervises the power supply

(VDD). At power-up, the device is inactive until VDD reaches

2 V 10%. When VDD crosses this threshold, the power supply

monitor keeps the device in the inactive state for an additional

26 ms to allow VDD to rise to 3.3 V − 10%, the minimum

recommended supply voltage.

Immediately after entering PSM0 mode, all registers in the

ADE7854/ADE7858/ADE7868/ADE7878 are set to their default

values, including the CONFIG2 and LPOILVL registers.

The ADE7854/ADE7858/ADE7868/ADE7878 signal the end of

IRQ1

the transition period by pulling the

interrupt pin low and

setting Bit 15 (RSTDONE) in the STATUS1 register to 1. This

bit is cleared to 0 during the transition period and is set to 1

when the transition ends. Writing the STATUS1 register with

the RSTDONE bit set to 1 clears the status bit and returns the

The PM0 and PM1 pins have internal pull-up resistors, but it is

necessary to set the PM1 pin to Logic 0 either through a

microcontroller or by grounding the PM1 pin externally, before

powering up the chip. The PM0 pin can remain open as it is

held high, due to the internal pull-up resistor. This ensures that

ADE7854/ADE7858/ADE7868/ADE7878 always power up in

PSM0 (normal) mode. The time taken from the chip being

powered up completely to the state where all functionality is

enabled, is about 40 ms (see Figure 26). It is necessary to ensure

IRQ1

pin high. Because RSTDONE is an unmaskable interrupt,

Bit 15 (RSTDONE) in the STATUS1 register must be cancelled

IRQ1 IRQ1

for the

pin to return high. Wait until the

pin goes low

before accessing the STATUS1 register to test the state of the

RSTDONE bit. At this point, as a good programming practice,

cancel all other status flags in the STATUS1 and STATUS0 registers

by writing the corresponding bits with 1.

RESET

that the

procedure.

pin is held high during the entire power-up

Initially, the DSP is in idle mode and, therefore, does not

execute any instructions. This is the moment to initialize all

registers in the ADE7854, ADE7858, ADE7868, or ADE7878.

See the Digital Signal Processor section for the proper procedure

to initialize all registers and start the metering.

If PSM0 mode is the only desired power mode, the PM1 pin can

be tied to ground externally. When the ADE7854/ADE7858/

ADE7868/ADE7878 enter PSM0 mode, the I²C port is the active

SS

serial port. To use the SPI port, toggle the /HSA pin three times

If the supply voltage, VDD, falls lower than 2 V 10%, the

ADE7854/ADE7858/ADE7868/ADE7878 enter an inactive

state, which means that no measurements or computations

are executed.

from high to low.

To lock I²C as the active serial port, set Bit 1 (I2C_LOCK) of the

CONFIG2 register to 1. From this moment, the device ignores

SS

spurious toggling of the /HSA pin, and a switch to the SPI

port is no longer possible.

If SPI is the active serial port, any write to the CONFIG2 register

locks the port, and a switch to the I²C port is no longer possible.

To use the I²C port, the ADE7854/ADE7858/ADE7868/ADE7878

must be powered down or the device must be reset by setting

RESET

the

pin low. After the serial port is locked, the serial port

selection is maintained when the device changes from one

PSMx power mode to another.

Rev. H | Page 26 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

HARDWARE RESET

SOFTWARE RESET FUNCTIONALITY

RESET

Bit 7 (SWRST) in the CONFIG register manages the software

reset functionality in PSM0 mode. The default value of this bit is 0.

If this bit is set to 1, then the ADE7854/ADE7858/ADE7868/

ADE7878 enter the software reset state. In this state, almost all

internal registers are set to their default values. In addition, the

choice of which serial port, I²C or SPI, is in use remains unchanged

if the lock-in procedure has been executed previously (see the

Serial Interfaces for details). The registers that maintain their

values despite the SWRST bit being set to 1 are the CONFIG2

and LPOILVL registers. When the software reset ends, Bit 7

The ADE7854/ADE7858/ADE7868/ADE7878 each has a

pin. If the ADE7854, ADE7858, ADE7868, or ADE7878 is in

RESET

PSM0 mode and the

enters the hardware reset state. The ADE78xx must be in PSM0

RESET

pin is set low, then the ADE78xx

mode for a hardware reset to be considered. Setting the

pin low while the ADE78xx is in PSM1, PSM2, and PSM3

modes does not have any effect.

If the ADE7854, ADE7858, ADE7868, or ADE7878 is in PSM0

RESET

mode and the

pin is toggled from high to low and then

back to high after at least 10 µs, all the registers are set to their

default values, including the CONFIG2 and LPOILVL registers.

The ADE78xx signals the end of the transition period by triggering

interrupt pin low and setting Bit 15 (RSTDONE) in the

STATUS1 register to 1. This bit is 0 during the transition period

and becomes 1 when the transition ends. The status bit is cleared

IRQ1

(SWRST) in the CONFIG register is cleared to 0, the

interrupt pin is set low, and Bit 15 (RSTDONE) in the STATUS1

register is set to 1. This bit is 0 during the transition period and

becomes 1 when the transition ends. The status bit is cleared and

IRQ1

the

IRQ1

the

pin is set back high by writing to the STATUS1 register

with the corresponding bit set to 1.

IRQ1

and the

pin is returned high by writing to the STATUS1

After a software reset ends, the DSP is in idle mode, which

means it does not execute any instruction. It is recommended

to initialize all the ADE7854/ADE7858/ADE7868/ADE7878

registers and then enable the data memory RAM protection and

write 0x0001 into the run register to start the DSP (see the

Digital Signal Processor section for details on data memory

RAM protection and the run register).

register with the corresponding bit set to 1.

After a hardware reset, the DSP is in idle mode, which means it

does not execute any instruction.

Because the I²C port is the default serial port of the ADE7854/

ADE7858/ADE7868/ADE7878, it becomes active after a reset

state. If SPI is the port used by the external microprocessor, the

procedure to enable it must be repeated immediately after the

Software reset functionality is not available in PSM1, PSM2, or

PSM3 mode.

RESET

pin is toggled back to high (see the Serial Interfaces

section for details).

At this point, it is recommended to initialize all of the ADE78xx

registers, enable data memory RAM protection, and then write

0x0001 into the run register to start the DSP. See the Digital

Signal Processor section for details on data memory RAM

protection and the run register.

Rev. H | Page 27 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

THEORY OF OPERATION

Figure 29 shows how the gain selection from the gain register

works in both current and voltage channels.

ANALOG INPUTS

The ADE7868/ADE7878 have seven analog inputs forming

current and voltage channels. The ADE7854/ADE7858 have six

analog inputs, not offering the neutral current. The current

channels consist of four pairs of fully differential voltage inputs:

IAP and IAN, IBP and IBN, ICP and ICN, and INP and INN.

These vol-tage input pairs have a maximum differential signal of

0.5 V. In addition, the maximum signal level on analog inputs

for the IxP/IxN pair is 0.5 V with respect to AGND. The

maximum common-mode signal allowed on the inputs is 25 mV.

Figure 27 presents a schematic of the input for the current

channels and their relation to the maximum common-mode

voltage.

GAIN

SELECTION

IxP, VyP

V

K × V

IN

IxN, VN

NOTES

1. x = A, B, C, N

y = A, B, C.

Figure 29. PGA in Current and Voltage Channels

ANALOG-TO-DIGITAL CONVERSION

The ADE7868/ADE7878 have seven sigma-delta (Σ-Δ) analog-

to-digital converters (ADCs), and the ADE7854/ADE7858 have

six Σ-Δ ADCs. In PSM0 mode, all ADCs are active. In PSM1

mode, only the ADCs that measure the Phase A, Phase B, and

Phase C currents are active. The ADCs that measure the neutral

current and the A, B, and C phase voltages are turned off. In

PSM2 and PSM3 modes, the ADCs are powered down to

minimize power consumption.

DIFFERENTIAL INPUT

V

+ V = 500mV MAX PEAK

1

2

COMMON MODE

V

+ V

2

1

V

= ±25mV MAX

CM

IAP, IBP,

ICP, OR INP

+500mV

V

1

2

V

CM

IAN, IBN,

ICN, OR INN

V

CM

–500mV

For simplicity, the block diagram in Figure 30 shows a first-

order Σ-Δ ADC. The converter is composed of the Σ-Δ modulator

and the digital low-pass filter.

Figure 27. Maximum Input Level, Current Channels, Gain = 1

All inputs have a programmable gain amplifier (PGA) with a

possible gain selection of 1, 2, 4, 8, or 16. The gain of IA, IB, and

IC inputs is set in Bits[2:0] (PGA1[2:0]) of the gain register. For

the ADE7868 and ADE7878 only, the gain of the IN input is set

in Bits[5:3] (PGA2[2:0]) of the gain register; thus, a different gain

from the IA, IB, or IC inputs is possible. See Table 44 for details

on the gain register.

CLKIN/16

ANALOG

LOW-PASS FILTER

DIGITAL

LOW-PASS

FILTER

INTEGRATOR

LATCHED

COMPARATOR

R

+

–

C

24

V

REF

.....10100101.....

1-BIT DAC

The voltage channel has three single-ended voltage inputs: VAP,

VBP, and VCP. These single-ended voltage inputs have a maximum

input voltage of 0.5 V with respect to VN. In addition, the max-

imum signal level on analog inputs for VxP and VN is 0.5 V

with respect to AGND. The maximum common-mode signal

allowed on the inputs is 25 mV. Figure 28 presents a schematic

of the voltage channels inputs and their relation to the maximum

common-mode voltage.

Figure 30. First-Order Σ-∆ ADC

A Σ-Δ modulator converts the input signal into a continuous

serial stream of 1s and 0s at a rate determined by the sampling

clock. In the ADE7854/ADE7858/ADE7868/ADE7878, the

sampling clock is equal to 1.024 MHz (CLKIN/16). The 1-bit

DAC in the feedback loop is driven by the serial data stream.

The DAC output is subtracted from the input signal. If the loop

gain is high enough, the average value of the DAC output (and,

therefore, the bit stream) can approach that of the input signal

level. For any given input value in a single sampling interval, the

data from the 1-bit ADC is virtually meaningless. Only when a

large number of samples are averaged is a meaningful result

obtained. This averaging is carried out in the second part of the

ADC, the digital low-pass filter. By averaging a large number of

bits from the modulator, the low-pass filter can produce 24-bit

data-words that are proportional to the input signal level.

DIFFERENTIAL INPUT

V

+ V = 500mV MAX PEAK

1

2

COMMON MODE

V

1

V

= ±25mV MAX

CM

VAP, VBP,

+500mV

OR VCP

V

1

V

CM

VN

V

CM

–500mV

Figure 28. Maximum Input Level, Voltage Channels, Gain = 1

All inputs have a programmable gain with a possible gain

selection of 1, 2, 4, 8, or 16. To set the gain, use Bits[8:6]

(PGA3[2:0]) in the gain register (see Table 44).

The Σ-Δ converter uses two techniques to achieve high resolu-

tion from what is essentially a 1-bit conversion technique. The

first is oversampling. Oversampling means that the signal is

sampled at a rate (frequency) that is many times higher than

Rev. H | Page 28 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

the bandwidth of interest. For example, the sampling rate in

the ADE7854/ADE7858/ADE7868/ADE7878 is 1.024 MHz,

and the bandwidth of interest is 40 Hz to 2 kHz. Oversampling

has the effect of spreading the quantization noise (noise due to

sampling) over a wider bandwidth. With the noise spread more

thinly over a wider bandwidth, the quantization noise in the band

of interest is lowered, as shown in Figure 31. However, oversam-

pling alone is not efficient enough to improve the signal-to-noise

ratio (SNR) in the band of interest. For example, an oversampling

factor of 4 is required just to increase the SNR by a mere 6 dB

(1 bit). To keep the oversampling ratio at a reasonable level, it is

possible to shape the quantization noise so that the majority of

the noise lies at the higher frequencies. In the Σ-Δ modulator,

the noise is shaped by the integrator, which has a high-pass-type

response for the quantization noise. This is the second technique

used to achieve high resolution. The result is that most of the

noise is at the higher frequencies where it can be removed by

the digital low-pass filter. This noise shaping is shown in Figure 31.

and prevent the distortion of the band of interest, a low-pass

filer (LPF) must be introduced. For conventional current

sensors, it is recommended to use one RC filter with a corner

frequency of 5 kHz for the attenuation to be sufficiently high at

the sampling frequency of 1.024 MHz. The 20 dB per decade

attenuation of this filter is usually sufficient to eliminate the

effects of aliasing for conventional current sensors. However, for a

di/dt sensor such as a Rogowski coil, the sensor has a 20 dB per

decade gain. This neutralizes the 20 dB per decade attenuation

produced by the LPF. Therefore, when using a di/dt sensor, take

care to offset the 20 dB per decade gain. One simple approach is

to cascade one additional RC filter, thereby producing a −40 dB

per decade attenuation.

ALIASING EFFECTS

SAMPLING

FREQUENCY

ANTIALIAS FILTER

0

2

4

512

1024

(RC)

DIGITAL FILTER

SIGNAL

FREQUENCY (kHz)

SHAPED NOISE

IMAGE

SAMPLING

FREQUENCY

FREQUENCIES

Figure 32. Aliasing Effects

NOISE

ADC Transfer Function

0

2

4

512

1024

All ADCs in the ADE7854/ADE7858/ADE7868/ADE7878 are

designed to produce the same 24-bit signed output code for the

same input signal level. With a full-scale input signal of 0.5 V

and an internal reference of 1.2 V, the ADC output code is nomi-

nally 5,928,256 (0x5A7540). The code from the ADC can vary

between 0x800000 (−8,388,608) and 0x7FFFFF (+8,388,607);

this is equivalent to an input signal level of 0.707 V. How e v e r,

for specified performance, do not exceed the nominal range of

0.5 V; ADC performance is guaranteed only for input signals

lower than 0.5 V.

FREQUENCY (kHz)

HIGH RESOLUTION

OUTPUT FROM

DIGITAL LPF

SIGNAL

NOISE

0

2

4

512

1024

FREQUENCY (kHz)

Figure 31. Noise Reduction Due to Oversampling and

Noise Shaping in the Analog Modulator

CURRENT CHANNEL ADC

Antialiasing Filter

Figure 33 shows the ADC and signal processing path for

Input IA of the current channels (it is the same for IB and IC).

The ADC outputs are signed twos complement 24-bit data-

words and are available at a rate of 8 kSPS (thousand samples

per second). With the specified full-scale analog input signal

of 0.5 V, the ADC produces its maximum output code value.

Figure 33 shows a full-scale voltage signal applied to the differ-

ential inputs (IAP and IAN). The ADC output swings between

−5,928,256 (0xA58AC0) and +5,928,256 (0x5A7540). The

input, IN, corresponds to the neutral current of a 3-phase

system (available in the ADE7868 and ADE7878 only). If no

neutral line is present, connect this input to AGND. The

datapath of the neutral current is similar to the path of the

phase currents as shown in Figure 34.

Figure 30 also shows an analog low-pass filter (RC) on the input

to the ADC. This filter is placed outside the ADE7854/ADE7858/

ADE7868/ADE7878, and its role is to prevent aliasing. Aliasing

is an artifact of all sampled systems as shown in Figure 32. Aliasing

means that frequency components in the input signal to the

ADC, which are higher than half the sampling rate of the ADC,

appear in the sampled signal at a frequency below half the

sampling rate. Frequency components above half the sampling

frequency (also known as the Nyquist frequency, that is, 512 kHz)

are imaged or folded back down below 512 kHz. This happens

with all ADCs regardless of the architecture. In the example shown,

only frequencies near the sampling frequency, that is, 1.024 MHz,

move into the band of interest for metering, that is, 40 Hz to

2 kHz. To attenuate the high frequency (near 1.024 MHz) noise

Rev. H | Page 29 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

ZX SIGNAL

DATA RANGE

ZX DETECTION

LPF1

0x5A7540 =

+5,928,256

CURRENT PEAK,

OVERCURRENT

DETECT

0V

INTEN BIT

DSP

CURRENT RMS (IRMS)

CALCULATION

CONFIG[0]

PGA1 BITS

GAIN[2:0]

×1, ×2, ×4, ×8, ×16

HPFDIS

[23:0]

REFERENCE

ADC

IAWV WAVEFORM

SAMPLE REGISTER

0xA58AC0 =

–5,928,256

AIGAIN[23:0]

DIGITAL

INTEGRATOR

IAP

TOTAL/FUNDAMENTAL

ACTIVE AND REACTIVE

POWER CALCULATION

V

PGA1

IN

HPF

IAN

CURRENT CHANNEL

DATA RANGE AFTER

INTEGRATION

V

CURRENT CHANNEL

DATA RANGE

IN

+0.5V/GAIN

0x5A7540 =

+5,928,256

0V

0xA58AC0 =

–5,928,256

0xA58AC0 =

–5,928,256

–0.5V/GAIN

ANALOG INPUT RANGE

ADC OUTPUT RANGE

Figure 33. Current Channel Signal Path

INTEN BIT

DSP

CONFIG[0]

HPFDIS

PGA2 BITS

GAIN[5:3]

×1, ×2, ×4, ×8, ×16

REFERENCE

ADC

[23:0]

CURRENT RMS (IRMS)

CALCULATION

NIGAIN[23:0]

DIGITAL

INP

INTEGRATOR

INWV WAVEFORM

SAMPLE REGISTER

V

PGA2

IN

HPF

INN

Figure 34. Neutral Current Signal Path (ADE7868, ADE7878 Only)

most significant bits (MSBs) padded with 0s and sign extended

to 28 bits. See Figure 35 for details.

Current Waveform Gain Registers

There is a multiplier in the signal path of each phase and

neutral current. The current waveform can be changed by

100% by writing a corresponding twos complement number

to the 24-bit signed current waveform gain registers (AIGAIN,

BIGAIN, CIGAIN, and NIGAIN). For example, if 0x400000 is

written to those registers, the ADC output is scaled up by 50%.

To scale the input by −50%, write 0xC00000 to the registers.

Equation 3 describes mathematically the function of the current

waveform gain registers.

31

28 27

24 23

0

0000

24-BIT NUMBER

BITS[27:24] ARE

EQUAL TO BIT 23

BIT 23 IS A SIGN BIT

Figure 35. 24-Bit xIGAIN Transmitted as 32-Bit Words

Current Channel HPF

The ADC outputs can contain a dc offset. This offset can create

errors in power and rms calculations. High-pass filters (HPFs)

are placed in the signal path of the phase and neutral currents

and of the phase voltages. If enabled, the HPF eliminates any dc

offset on the current channel. All filters are implemented in the

DSP and, by default, they are all enabled: the 24-bit HPFDIS

register is cleared to 0x00000000. All filters are disabled by

setting HPFDIS to any nonzero value.

Current Waveform =

Content of CurrentGainRegister





ADCOutput 1



(3)

2²³







Changing the content of the AIGAIN, BIGAIN, CIGAIN, or

INGAIN registers affects all calculations based on its current;

that is, it affects the corresponding phase active/reactive/

apparent energy and current rms calculation. In addition,

waveform samples scale accordingly.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE78xx work on 32-, 16-, or 8-bit words.

The HPFDIS register is accessed as a 32-bit register with eight

MSBs padded with 0s. See Figure 36 for details.

Note that the serial ports of the ADE7854, ADE7858, ADE7868,

and/or ADE7878 work on 32-, 16-, or 8-bit words, and the DSP

works on 28 bits. The 24-bit AIGAIN, BIGAIN, CIGAIN, and

NIGAIN registers are accessed as 32-bit registers with the four

31

24 23

0

0000 0000

24-BIT NUMBER

Figure 36. 24-Bit HPFDIS Register Transmitted as 32-Bit Word

Rev. H | Page 30 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Current Channel Sampling

loop generate an electromotive force (EMF) between the two

ends of the loop. The EMF is a voltage signal that is propor-

tional to the di/dt of the current. The voltage output from the

di/dt current sensor is determined by the mutual inductance

between the current carrying conductor and the di/dt sensor.

The waveform samples of the current channel are taken at the

output of HPF and stored in the 24-bit signed registers, IAW V,

I BW V, ICWV, and INWV (ADE7868 and ADE7878 only) at a

rate of 8 kSPS. All power and rms calculations remain uninter-

rupted during this process. Bit 17 (DREADY) in the STATUS0

register is set when the IAWV, IBWV, ICWV, and INWV registers

are available to be read using the I²C or SPI serial port. Setting

Bit 17 (DREADY) in the MASK0 register enables an interrupt

to be set when the DREADY flag is set. See the Digital Signal

Processor section for more details on Bit DREADY.

Due to the di/dt sensor, the current signal needs to be filtered

before it can be used for power measurement. On each phase and

neutral current datapath, there is a built-in digital integrator to

recover the current signal from the di/dt sensor. The digital inte-

grator is disabled by default when the ADE78xx is powered up

and after a reset. Setting Bit 0 (INTEN) of the CONFIG register

turns on the integrator. Figure 39 and Figure 40 show the

magnitude and phase response of the digital integrator.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE78xx work on 32-, 16-, or 8-bit words.

When the IAW V, I BW V, IC W V, and INWV 24-bit signed

registers are read from the ADE78xx (INWV is available on

ADE7868/ADE7878 only), they are transmitted sign extended

to 32 bits. See Figure 37 for details.

Note that the integrator has a −20 dB/dec attenuation and

approximately −90° phase shift. When combined with a di/dt

sensor, the resulting magnitude and phase response should be a

flat gain over the frequency band of interest. However, the di/dt

sensor has a 20 dB/dec gain associated with it and generates sig-

nificant high frequency noise. An antialiasing filter of at least

the second order is needed to avoid noise aliasing back in the

band of interest when the ADC is sampling (see the Antialiasing

Filter section).

31

24 23 22

0

24-BIT SIGNED NUMBER

BITS[31:24] ARE

EQUAL TO BIT 23

BIT 23 IS A SIGN BIT

Figure 37. 24-Bit IxWV Register Transmitted as 32-Bit Signed Word

50

The ADE7854/ADE7858/ADE7868/ADE7878 devices each

contain a high speed data capture (HSDC) port that is specially

designed to provide fast access to the waveform sample registers.

See the HSDC Interface section for more details.

0

–50

0.01

0.1

1

10

100

1000

di/dt CURRENT SENSOR AND DIGITAL INTEGRATOR

FREQUENCY (Hz)

The di/dt sensor detects changes in the magnetic field caused by

the ac current. Figure 38 shows the principle of a di/dt current

sensor.

0

–50

MAGNETIC FIELD CREATED BY CURRENT

(DIRECTLY PROPORTIONAL TO CURRENT)

–100

0

500

1000

1500

2000

2500

3000

3500 4000

FREQUENCY (Hz)

Figure 39. Combined Gain and Phase Response of the

Digital Integrator

+

–

EMF (ELECTROMOTIVE FORCE)

INDUCED BY CHANGES IN

The DICOEFF 24-bit signed register is used in the digital

integrator algorithm. At power-up or after a reset, its value is

0x000000. Before turning on the integrator, this register must be

initialized with 0xFFF8000. DICOEFF is not used when the

integrator is turned off and can remain at 0x000000 in that case.

MAGNETIC FLUX DENSITY (di/dt)

Figure 38. Principle of a di/dt Current Sensor

The flux density of a magnetic field induced by a current is

directly proportional to the magnitude of the current. The

changes in the magnetic flux density passing through a conductor

Rev. H | Page 31 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

–15

32-bit register with four MSBs padded with 0s and sign

extended to 28 bits, which practically means it is transmitted

–20

equal to 0xFFF8000.

–25

–30

When the digital integrator is switched off, the ADE7854/

ADE7858/ ADE7868/ADE7878 can be used directly with a

conventional current sensor, such as a current transformer (CT).

30

35

40

45

50

55

60

65

70

FREQUENCY (Hz)

–89.96

VOLTAGE CHANNEL ADC

Figure 41 shows the ADC and signal processing chain for

Input VA in the voltage channel. The VB and VC channels

have similar processing chains. The ADC outputs are signed

twos complement 24-bit words and are available at a rate of

8 kSPS. With the specified full-scale analog input signal of

0.5 V, the ADC produces its maximum output code value.

Figure 41 shows a full-scale voltage signal being applied to the

differential inputs (VA and VN). The ADC output swings

between −5,928,256 (0xA58AC0) and +5,928,256 (0x5A7540).

–89.97

–89.98

–89.99

30

35

40

45

50

55

60

65

70

FREQUENCY (Hz)

Figure 40. Combined Gain and Phase Response of the

Digital Integrator (40 Hz to 70 Hz)

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE7854/ADE7858/ADE7868/ADE7878 work

on 32-, 16-, or 8-bit words. Similar to the registers shown in

Figure 35, the DICOEFF 24-bit signed register is accessed as a

VOLTAGE PEAK,

OVERVOLTAGE,

SAG DETECT

CURRENT RMS (VRMS)

CALCULATION

DSP

PGA3 BITS

GAIN[8:6]

×1, ×2, ×4, ×8, ×16

HPFDIS

[23:0]

REFERENCE

ADC

VAWV WAVEFORM

AVGAIN[23:0]

SAMPLE REGISTER

VAP

TOTAL/FUNDAMENTAL

ACTIVE AND REACTIVE

POWER CALCULATION

V

PGA3

IN

HPF

VN

V

VOLTAGE CHANNEL

DATA RANGE

IN

ZX DETECTION

LPF1

+0.5V/GAIN

0x5A7540 =

+5,928,256

ZX SIGNAL

DATA RANGE

0V

0x5A7540 =

+5,928,256

0xA58AC0 =

–5,928,256

–0.5V/GAIN

0V

ANALOG INPUT RANGE

ANALOG OUTPUT RANGE

0xA58AC0 =

–5,928,256

Figure 41. Voltage Channel Datapath

Rev. H | Page 32 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Voltage Waveform Gain Registers

CHANGING PHASE VOLTAGE DATAPATH

There is a multiplier in the signal path of each phase voltage.

The voltage waveform can be changed by 100% by writing

a corresponding twos complement number to the 24-bit signed

voltage waveform gain registers (AVGAIN, BVGAIN, and

CVGAIN). For example, if 0x400000 is written to those registers,

the ADC output is scaled up by 50%. To scale the input by −50%,

write 0xC00000 to the registers. Equation 4 describes mathe-

matically the function of the current waveform gain registers.

The ADE7854/ADE7858/ADE7868/ADE7878 can direct one

phase voltage input to the computational datapath of another

phase. For example, Phase A voltage can be introduced in the

Phase B computational datapath, which means all powers

computed by the ADE78xx in Phase B are based on Phase A

voltage and Phase B current.

Bits[9:8] (VTOIA[1:0]) of the CONFIG register manage what

phase voltage is directed to Phase A computational data path. If

VTOIA[1:0] = 00 (default value), the Phase A voltage is directed

to the Phase A computational data path. If VTOIA[1:0] = 01,

the Phase B voltage is directed to the Phase A computational

data path. If VTOIA[1:0] = 10, the Phase C voltage is directed

to the Phase A computational data path. If VTOIA[1:0] = 11,

the ADE7854/ADE7858/ADE7868/ADE7878 behaves as if

VTOIA[1:0] = 00.

Voltage Waveform =

Content of VoltageGainRegister





ADC Output ×1+



(4)

2²³







Changing the content of the AVGAIN, BVGAIN, and CVGAIN

registers affects all calculations based on its voltage; that is, it

affects the corresponding phase active/reactive/apparent energy

and voltage rms calculation. In addition, waveform samples are

scaled accordingly.

Bits[11:10] (VTOIB[1:0]) of the CONFIG register manage

what phase voltage is directed to the Phase B computational

data path. If VTOIB[1:0] = 00 (default value), the Phase B

voltage is directed to the Phase B computational data path.

If VTOIB[1:0] = 01, the Phase C voltage is directed to the

Phase B computational data path. If VTOIB[1:0] = 10, the Phase A

voltage is directed to the Phase B computational data path. If

VTOIB[1:0] = 11, the ADE7854/ADE7858/ADE7868/ADE7878

behaves as if VTOIB[1:0] = 00.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE78xx work on 32-, 16-, or 8-bit words,

and the DSP works on 28 bits. As presented in Figure 35, the

AVGAIN, BVGAIN, and CVGAIN registers are accessed as

32-bit registers with four MSBs padded with 0s and sign

extended to 28 bits.

Voltage Channel HPF

As explained in the Current Channel HPF section, the ADC

outputs can contain a dc offset that can create errors in power

and rms calculations. HPFs are placed in the signal path of the

phase voltages, similar to the ones in the current channels. The

HPFDIS register can enable or disable the filters. See the

Current Channel HPF section for more details.

Bits[13:12] (VTOIC[1:0]) of the CONFIG register manage what

phase voltage is directed to the Phase C computational data

path. If VTOIC[1:0] = 00 (default value), the Phase C voltage is

directed to Phase C computational data path, if VTOIC[1:0] =

01, the Phase A voltage is directed to the Phase C computational

data path. If VTOIC[1:0] = 10, the Phase B voltage is directed to

the Phase C computational data path. If VTOIC[1:0] = 11, the

ADE7854/ADE7858/ADE7868/ADE7878 behaves as if

VTOIC[1:0] = 00.

Voltage Channel Sampling

The waveform samples of the voltage channel are taken at the

output of HPF and stored into VAWV, VBWV, and VCWV

24-bit signed registers at a rate of 8 kSPS. All power and rms

calculations remain uninterrupted during this process. Bit 17

(DREADY) in the STATUS0 register is set when the VAW V,

VBWV, and VCWV registers are available to be read using the

I²C or SPI serial port. Setting Bit 17 (DREADY) in the MASK0

register enables an interrupt to be set when the DREADY flag is

set. See the Digital Signal Processor section for more details on

Bit DREADY.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE78xx work on 32-, 16-, or 8-bit words.

Similar to registers presented in Figure 37, the VAWV, VBWV,

and VCWV 24-bit signed registers are transmitted sign

extended to 32 bits.

The ADE7854/ADE7858/ADE7868/ADE7878 each contain an

HSDC port especially designed to provide fast access to the

waveform sample registers. See the HSDC Interface section for

more details.

Rev. H | Page 33 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

IA

DSP

IA, IB, IC,

OR

VA, VB, VC

HPFDIS

[23:0]

REFERENCE

ADC

xIGAIN[23:0] OR

xVGAIN[23:0]

PHASE A

COMPUTATIONAL

DATAPATH

APHCAL

BPHCAL

CPHCAL

ZX

DETECTION

VTOIB[1:0] = 10,

PHASE A VOLTAGE

DIRECTED

VA

IB

PGA

HPF

LPF1

TO PHASE B

39.6° OR 2.2ms @ 50Hz

PHASE B

COMPUTATIONAL

DATAPATH

1

0.855

VTOIC[1:0] = 10,

PHASE B VOLTAGE

DIRECTED

ZX

VB

IC

0V

ZX

TO PHASE C

IA, IB, IC,

OR VA, VB, VC

LPF1 OUTPUT

PHASE C

COMPUTATIONAL

DATAPATH

Figure 43. Zero-Crossing Detection on Voltage and Current Channels

VTOIA[1:0] = 10,

PHASE C VOLTAGE

DIRECTED

To provide further protection from noise, input signals to the

voltage channel with amplitude lower than 10% of full scale do

not generate zero-crossing events at all. The Current Channel ZX

detection circuit is active for all input signals independent of their

amplitudes.

VC

TO PHASE A

Figure 42. Phase Voltages Used in Different Datapaths

Figure 42 presents the case in which Phase A voltage is used in

the Phase B datapath, Phase B voltage is used in the Phase C

datapath, and Phase C voltage is used in the Phase A datapath.

The ADE7854/ADE7858/ADE7868/ADE7878 contain six zero-

crossing detection circuits, one for each phase voltage and

current channel. Each circuit drives one flag in the STATUS1

register. If a circuit placed in the Phase A voltage channel

detects one zero-crossing event, Bit 9 (ZXVA) in the STATUS1

register is set to 1.

POWER QUALITY MEASUREMENTS

Zero-Crossing Detection

The ADE7854/ADE7858/ADE7868/ADE7878 have a zero-

crossing (ZX) detection circuit on the phase current and voltage

channels. The neutral current datapath does not contain a zero-

crossing detection circuit. Zero-crossing events are used as a

time base for various power quality measurements and in the

calibration process.

Similarly, the Phase B voltage circuit drives Bit 10 (ZXVB), the

Phase C voltage circuit drives Bit 11 (ZXVC), and circuits placed

in the current channel drive Bit 12 (ZXIA), Bit 13 (ZXIB), and

Bit 14 (ZXIC) in the STATUS1 register. If a ZX detection bit is

IRQ1

set in the MASK1 register, the

and the corresponding status flag is set to 1. The status bit is

IRQ1

interrupt pin is driven low

The output of LPF1 is used to generate zero crossing events.

The low-pass filter is intended to eliminate all harmonics of

50 Hz and 60 Hz systems, and to help identify the zero-crossing

events on the fundamental components of both current and

voltage channels.

cleared and the

pin is set to high by writing to the STATUS1

register with the status bit set to 1.

Zero-Crossing Timeout

Every zero-crossing detection circuit has an associated timeout

register. This register is loaded with the value written into the

16-bit ZXTOUT register and is decremented (1 LSB) every

62.5 μs (16 kHz clock). The register is reset to the ZXTOUT

value every time a zero crossing is detected. The default value of

this register is 0xFFFF. If the timeout register decrements to 0

before a zero crossing is detected, one of Bits[8:3] of the

STATUS1 register is set to 1. Bit 3 (ZXTOVA), Bit 4 (ZXTOVB),

and Bit 5 (ZXTOVC) in the STATUS1 register refer to Phase A,

Phase B, and Phase C of the voltage channel; Bit 6 (ZXTOIA),

Bit 7 (ZXTOIB), and Bit 8 (ZXTOIC) in the STATUS1 register

refer to Phase A, Phase B, and Phase C of the current channel.

The digital filter has a pole at 80 Hz and is clocked at 256 kHz.

As a result, there is a phase lag between the analog input signal

(one of IA, IB, IC, VA, VB, and VC) and the output of LPF1.

The error in ZX detection is 0.0703° for 50 Hz systems (0.0843°

for 60 Hz systems). The phase lag response of LPF1 results in a

time delay of approximately 31.4° or 1.74 ms (at 50 Hz) between

its input and output. The overall delay between the zero crossing

on the analog inputs and ZX detection obtained after LPF1 is

about 39.6° or 2.2 ms (at 50 Hz). The ADC and HPF introduce

the additional delay. The LPF1 cannot be disabled to assure a

good resolution of the ZX detection. Figure 43 shows how the

zero-crossing signal is detected.

If a ZXTOIx or ZXTOVx bit is set in the MASK1 register, the

IRQ1

interrupt pin is driven low when the corresponding status bit

IRQ1

is set to 1. The status bit is cleared and the

pin is returned to

high by writing to the STATUS1 register with the status bit set to 1.

The resolution of the ZXOUT register is 62.5 μs (16 kHz clock)

per LSB. Thus, the maximum timeout period for an interrupt is

4.096 sec: 2¹⁶/16 kHz.

Rev. H | Page 34 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Figure 44 shows the mechanism of the zero-crossing timeout

detection when the voltage or the current signal stays at a fixed

dc level for more than 62.5 µs × ZXTOUT µs.

PHASE A

PHASE C

PHASE B

A, B, C PHASE

VOLTAGES AFTER

LPF1

16-BIT INTERNAL

REGISTER VALUE

ZXTOUT

ZX A

ZX C

ZX B

BIT 19 (SEQERR) IN

STATUS1 REGISTER

VOLTAGE

OR

CURRENT

0V

IRQ1

SIGNAL

STATUS1[19] SET TO 1

STATUS1[19] CANCELLED

BY A WRITE TO THE

STATUS1 REGISTER WITH

SEQERR BIT SET

ZXZOxy FLAG IN

STATUS1[31:0], x = V, A

y = A, B, C

Figure 45. SEQERR Bit Set to 1 When Phase A Voltage Is Followed by

Phase C Voltage

Once a phase sequence error has been detected, the time

measurement between various phase voltages (see the Time

Interval Between Phases section) can help to identify which

phase voltage should be considered with another phase current

in the computational datapath. Bits[9:8] (VTOIA[1:0]), Bits[11:10]

(VTOIB[1:0]), and Bits[13:12] (VTOIC[1:0]) in the CONFIG

register can be used to direct one phase voltage to the datapath

of another phase. See the Changing Phase Voltage Datapath

section for details.

IRQ1 INTERRUPT PIN

Figure 44. Zero-Crossing Timeout Detection

Phase Sequence Detection

The ADE7854/ADE7858/ADE7868/ADE7878 have on-chip

phase sequence error detection circuits. This detection works

on phase voltages and considers only the zero crossings

determined by their negative-to-positive transitions. The regular

succession of these zero-crossing events is Phase A followed by

Phase B followed by Phase C (see Figure 46). If the sequence of

zero-crossing events is, instead, Phase A followed by Phase C

followed by Phase B, then Bit 19 (SEQERR) in the STATUS1

register is set.

Time Interval Between Phases

The ADE7854/ADE7858/ADE7868/ADE7878 have the capa-

bility to measure the time delay between phase voltages, between

phase currents, or between voltages and currents of the same

phase. The negative-to-positive transitions identified by the zero-

crossing detection circuit are used as start and stop measuring

points. Only one set of such measurements is available at one time,

based on Bits[10:9] (ANGLESEL[1:0]) in the COMPMODE

register.

If Bit 19 (SEQERR) in the MASK1 register is set to 1 and a

phase sequence error event is triggered, the

is driven low. The status bit is cleared and the

high by writing to the STATUS1 register with the Status Bit 19

(SEQERR) set to 1.

IRQ1

interrupt pin

IRQ1

pin is set

PHASE A

PHASE B

PHASE C

The phase sequence error detection circuit is functional only

when the ADE78xx is connected in a 3-phase, 4-wire, three voltage

sensors configuration (Bits[5:4], CONSEL[1:0] in the ACCMODE

register, set to 00). In all other configurations, only two voltage

sensors are used; therefore, it is not recommended to use the

detection circuit. In these cases, use the time intervals between

phase voltages to analyze the phase sequence (see the Time

Interval Between Phases section for details).

ZX A

ZX B

ZX C

Figure 46. Regular Succession of Phase A, Phase B, and Phase C

When the ANGLESEL[1:0] bits are set to 00, the default value,

the delays between voltages and currents on the same phase are

measured. The delay between Phase A voltage and Phase A

current is stored in the 16-bit unsigned ANGLE0 register (see

Figure 47 for details). In a similar way, the delays between voltages

and currents on Phase B and Phase C are stored in the ANGLE1

and ANGLE2 registers, respectively.

Figure 45 presents the case in which Phase A voltage is not

followed by Phase B voltage but by Phase C voltage. Every time

a negative-to-positive zero crossing occurs, Bit 19 (SEQERR) in

the STATUS1 register is set to 1 because such zero crossings on

Phase C, Phase B, or Phase A cannot come after zero crossings

from Phase A, Phase C, or respectively, Phase B zero crossings.

Rev. H | Page 35 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

PHASE A

VOLTAGE

LPF1 filter (see Figure 43), a settling time of 30 ms to 40 ms is

associated with this filter before the measurement is stable.

PHASE A

CURRENT

The period measurement has a resolution of 3.90625 μs/LSB

(256 kHz clock), which represents 0.0195% (50 Hz/256 kHz)

when the line frequency is 50 Hz and 0.0234% (60 Hz/256 kHz)

when the line frequency is 60 Hz. The value of the period register

for 50 Hz networks is approximately 5120 (256 kHz/50 Hz) and

for 60 Hz networks is approximately 4267 (256 kHz/60 Hz). The

length of the register enables the measurement of line frequencies

as low as 3.9 Hz (256 kHz/2¹⁶). The period register is stable at

1 LSB when the line is established and the measurement does

not change.

ANGLE0

Figure 47. Delay Between Phase A Voltage and Phase A Current Is

Stored in the ANGLE0 Register

When the ANGLESEL[1:0] bits are set to 01, the delays between

phase voltages are measured. The delay between Phase A voltage

and Phase C voltage is stored into the ANGLE0 register. The

delay between Phase B voltage and Phase C voltage is stored in

the ANGLE1 register, and the delay between Phase A voltage

and Phase B voltage is stored in the ANGLE2 register (see

Figure 48 for details).

The following expressions can be used to compute the line

period and frequency using the period register:

PERIOD[15:0] +1

T_L=

f_L

[

sec

]

(6)

(7)

256E3

When the ANGLESEL[1:0] bits are set to 10, the delays between

phase currents are measured. Similar to delays between phase

voltages, the delay between Phase A and Phase C currents is stored

into the ANGLE0 register, the delay between Phase B and Phase C

currents is stored in the ANGLE1 register, and the delay between

Phase A and Phase B currents is stored into the ANGLE2

register (see Figure 48 for details).

256E3

PERIOD[15:0] +1

=

[Hz]

Phase Voltage Sag Detection

The ADE7854/ADE7858/ADE7868/ADE7878 can be pro-

grammed to detect when the absolute value of any phase voltage

drops below a certain peak value for a number of half-line cycles.

The phase where this event takes place is identified in Bits[14:12]

(VSPHASE[x]) of the PHSTATUS register. This condition is

illustrated in Figure 49.

PHASE A

PHASE B

PHASE C

PHASE B VOLTAGE

FULL SCALE

SAGLVL[23:0]

ANGLE2

ANGLE1

ANGLE0

Figure 48. Delays Between Phase Voltages (Currents)

SAGCYC[7:0] = 0x4

PHASE A VOLTAGE

The ANGLE0, ANGLE1, and ANGLE2 registers are 16-bit

unsigned registers with 1 LSB corresponding to 3.90625 μs

(256 kHz clock), which means a resolution of 0.0703° (360° ×

50 Hz/256 kHz) for 50 Hz systems and 0.0843° (360° × 60 Hz/

256 kHz) for 60 Hz systems. The delays between phase voltages

or phase currents are used to characterize how balanced the

load is. The delays between phase voltages and currents are

used to compute the power factor on each phase as shown in

the following Equation 5:

FULL SCALE

SAGLVL[23:0]

STATUS1[16] AND

PHSTATUS[12]

CANCELLED BY A

WRITE TO

STATUS1[31:0]

WITH SAG BIT SET

SAGCYC[7:0] = 0x4

BIT 16 (SAG) IN

STATUS1[31:0]

360^× f_LINE

256 kHz







cosφ_x= cos ANGLEx ×

(5)









IRQ1 PIN

where f_LINE= 50 Hz or 60 Hz.

STATUS[16] AND

PHSTATUS[13]

SET TO 1

Period Measurement

VSPHASE[0] =

PHSTATUS[12]

The ADE7854/ADE7858/ADE7868/ADE7878 provide the

period measurement of the line in the voltage channel. Bits[1:0]

(PERSEL[1:0]) in the MMODE register select the phase voltage

used for this measurement. The period register is a 16-bit

unsigned register and updates every line period. Because of the

VSPHASE[1] =

PHSTATUS[13]

Figure 49. SAG Detection

Rev. H | Page 36 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Figure 49 shows Phase A voltage falling below a threshold that

is set in the SAG level register (SAGLVL) for four half-line cycles

(SAGCYC = 4). When Bit 16 (SAG) in the STATUS1 register is set

to 1 to indicate the condition, Bit VSPHASE[0] in the PHSTATUS

register is also set to 1 because the event happened on Phase A

Bit 16 (SAG) in the STATUS1 register. All Bits[14:12] (VSPHASE[2],

VSPHASE[1], and VSPHASE[0]) of the PHSTATUS register (not

just the VSPHASE[0] bit) are erased by writing the STATUS1

register with the SAG bit set to 1.

the SAG event is triggered continuously. Writing 0x00 or 0x01

puts the SAG detection level at 0, therefore, the SAG event is

never triggered.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE78xx work on 32-, 16-, or 8-bit words.

Similar to the register presented in Figure 36, the SAGLVL

register is accessed as a 32-bit register with eight MSBs padded

with 0s.

Peak Detection

The SAGCYC register represents the number of half-line cycles

the phase voltage must remain below the level indicated in the

SAGLVL register to trigger a SAG condition; 0 is not a valid

number for SAGCYC. For example, when the SAG cycle

(SAGCYC[7:0]) contains 0x07, the SAG flag in the STATUS1

register is set at the end of the seventh half line cycle for which

the line voltage falls below the threshold. If Bit 16 (SAG) in

The ADE7854/ADE7858/ADE7868/ADE7878 record the

maximum absolute values reached by the voltage and current

channels over a certain number of half-line cycles and stores

them into the less significant 24 bits of the VPEAK and IPEAK

32-bit registers.

The PEAKCYC register contains the number of half-line cycles

used as a time base for the measurement. The circuit uses the

zero-crossing points identified by the zero-crossing detection

circuit. Bits[4:2] (PEAKSEL[2:0]) in the MMODE register select

the phases upon which the peak measurement is performed. Bit 2

selects Phase A, Bit 3 selects Phase B, and Bit 4 selects Phase C.

Selecting more than one phase to monitor the peak values

decreases proportionally the measurement period indicated in

the PEAKCYC register because zero crossings from more

phases are involved in the process. When a new peak value is

determined, one of Bits[26:24] (IPPHASE[2:0] or VPPHASE[2:0])

in the IPEAK and VPEAK registers is set to 1, identifying the

phase that triggered the peak detection event. For example, if a

peak value has been identified on Phase A current, Bit 24

(IPPHASE[0]) in the IPEAK register is set to 1. If next time a

new peak value is measured on Phase B, Bit 24 (IPPHASE[0])

of the IPEAK register is cleared to 0, and Bit 25 (IPPHASE[1])

of the IPEAK register is set to 1. Figure 50 shows the composition

of the IPEAK and VPEAK registers.

IRQ1

MASK1 is set, the

interrupt pin is driven low in case of

a SAG event in the same moment the Status Bit 16 (SAG) in

STATUS1 register is set to 1. The SAG status bit in the STATUS1

register and all Bits[14:12] (VSPHASE[2], VSPHASE[1], and

VSPHASE[0]]) of the PHSTATUS register are cleared, and the

IRQ1

pin is returned to high by writing to the STATUS1

register with the status bit set to 1.

When the Phase B voltage falls below the indicated threshold

into the SAGLVL register for two line cycles, Bit VSPHASE[1]

in the PHSTATUS register is set to 1, and Bit VSPHASE[0] is

cleared to 0. Simultaneously, Bit 16 (SAG) in the STATUS1 register

is set to 1 to indicate the condition.

Note that the internal zero-crossing counter is always active. By

setting the SAGLVL register, the first SAG detection result is,

therefore, not executed across a full SAGCYC period. Writing to

the SAGCYC register when the SAGLVL register is already initia-

lized resets the zero-crossing counter, thus ensuring that the first

SAG detection result is obtained across a full SAGCYC period.

IPPHASE/VPPHASE BITS

31

00000

27 26 25 24 23

24 BIT UNSIGNED NUMBER

0

The recommended procedure to manage SAG events is the

following:

PEAK DETECTED

ON PHASE C

PEAK DETECTED

ON PHASE A

1. Enable SAG interrupts in the MASK1 register by setting

Bit 16 (SAG) to 1.

PEAK DETECTED

ON PHASE B

IRQ1

2. When a SAG event happens, the

interrupt pin goes

low and Bit 16 (SAG) in the STATUS1 is set to 1.

3. The STATUS1 register is read with Bit 16 (SAG) set to 1.

4. The PHSTATUS register is read, identifying on which

phase or phases a SAG event happened.

Figure 50. Composition of IPEAK[31:0] and VPEAK[31:0] Registers

5. The STATUS1 register is written with Bit 16 (SAG) set to 1.

Immediately, the SAG bit and all Bits[14:12] (VSPHASE[2],

VSPHASE[1], and VSPHASE[0]) of the PHSTATUS register

are erased.

SAG Level Set

The content of the SAGLVL[23:0] SAG level register is compared

to the absolute value of the output from HPF. Writing 5,928,256

(0x5A7540) to the SAGLVL register, puts the SAG detection

level at full scale (see the Voltage Channel ADC section), thus;

Rev. H | Page 37 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

PEAK VALUE WRITTEN INTO

IPEAK AT THE END OF FIRST

PEAKCYC PERIOD

thereby ensuring that the first peak detection result is obtained

across a full PEAKCYC period.

END OF FIRST

PEAKCYC = 16 PERIOD

Overvoltage and Overcurrent Detection

END OF SECOND

PEAKCYC = 16 PERIOD

The ADE7854/ADE7858/ADE7868/ADE7878 detect when the

instantaneous absolute value measured on the voltage and

current channels becomes greater than the thresholds set in the

OVLVL and OILVL 24-bit unsigned registers. If Bit 18 (OV) in

PHASE A

CURRENT

IRQ1

the MASK1 register is set, the

in case of an overvoltage event. There are two status flags set

IRQ1

interrupt pin is driven low

BIT 24 OF IPEAK

CLEARED TO 0 AT

THE END OF SECOND

PEAKCYC PERIOD

BIT 24

OF IPEAK

when the

interrupt pin is driven low: Bit 18 (OV) in the

STATUS1 register and one of Bits[11:9] (OVPHASE[2:0]) in the

PHSTATUS register to identify the phase that generated the

overvoltage. The Status Bit 18 (OV) in the STATUS1 register

and all Bits[11:9] (OVPHASE[2:0]) in the PHSTATUS register

PHASE B

CURRENT

IRQ1

are cleared, and the

pin is set to high by writing to the

BIT 25 OF IPEAK

PEAK VALUE WRITTEN INTO

IPEAK AT THE END OF SECOND

PEAKCYC PERIOD

SET TO 1 AT THE

END OF SECOND

PEAKCYC PERIOD

STATUS1 register with the status bit set to 1. Figure 52 presents

overvoltage detection in Phase A voltage.

BIT 25

OF IPEAK

Figure 51. Peak Level Detection

PHASE A

VOLTAGE CHANNEL

OVERVOLTAGE

DETECTED

Figure 51 shows how the ADE78xx records the peak value on the

current channel when measurements on Phase A and Phase B are

enabled (Bit PEAKSEL[2:0] in the MMODE register are 011).

PEAKCYC is set to 16, meaning that the peak measurement

cycle is four line periods. The maximum absolute value of Phase A

is the greatest during the first four line periods (PEAKCYC = 16),

so the maximum absolute value is written into the less signifi-

cant 24 bits of the IPEAK register, and Bit 24 (IPPHASE[0]) of

the IPEAK register is set to 1 at the end of the period. This bit

remains at 1 for the duration of the second PEAKCYC period of

four line cycles. The maximum absolute value of Phase B is the

greatest during the second PEAKCYC period; therefore, the

maximum absolute value is written into the less significant

24 bits of the IPEAK register, and Bit 25 (IPPHASE[1]) in the

IPEAK register is set to 1 at the end of the period.

OVLVL[23:0]

BIT 18 (OV) OF

STATUS1

STATUS1[18] AND

PHSTATUS[9]

CANCELLED BY A

WRITE OF STATUS1

WITH OV BIT SET.

BIT 9 (OVPHASE)

OF PHSTATUS

At the end of the peak detection period in the current channel,

Bit 23 (PKI) in the STATUS1 register is set to 1. If Bit 23 (PKI)

IRQ1

in the MASK1 register is set, the

interrupt pin is driven low

Figure 52. Overvoltage Detection

at the end of PEAKCYC period and Status Bit 23 (PKI) in the

STATUS1 register is set to 1. In a similar way, at the end of the

peak detection period in the voltage channel, Bit 24 (PKV) in the

STATUS1 register is set to 1. If Bit 24 (PKV) in the MASK1

Whenever the absolute instantaneous value of the voltage goes

above the threshold from the OVLVL register, Bit 18 (OV) in

the STATUS1 register and Bit 9 (OVPHASE[0]) in the PHSTATUS

register are set to 1. Bit 18 (OV) of the STATUS1 register and

Bit 9 (OVPHASE[0]) in the PHSTATUS register are cancelled

when the STATUS1 register is written with Bit 18 (OV) set to 1.

IRQ1

register is set, the

interrupt pin is driven low at the end of

PEAKCYC period and Status Bit 24 (PKV) in the STATUS1

register is set to 1. To find the phase that triggered the interrupt,

one of either the IPEAK or VPEAK registers is read immediately

after reading the STATUS1 register. Next, the status bits are

The recommended procedure to manage overvoltage events is

the following:

IRQ1

cleared, and the

pin is set to high by writing to the

1. Enable OV interrupts in the MASK1 register by setting

Bit 18 (OV) to 1.

STATUS1 register with the status bit set to 1.

IRQ1

2. When an overvoltage event happens, the

pin goes low.

interrupt

Note that the internal zero-crossing counter is always active. By

setting Bits[4:2] (PEAKSEL[2:0]) in the MMODE register, the

first peak detection result is, therefore, not executed across a full

PEAKCYC period. Writing to the PEAKCYC register when the

PEAKSEL[2:0] bits are set resets the zero-crossing counter,

3. The STATUS1 register is read with Bit 18 (OV) set to 1.

4. The PHSTATUS register is read, identifying on which

phase or phases an overvoltage event happened.

Rev. H | Page 38 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

5. The STATUS1 register is written with Bit 18 (OV) set to 1.

In this moment, Bit OV is erased and also all Bits[11:9]

(OVPHASE[2:0]) of the PHSTATUS register.

ADC_MAX= 5,928,256, the ADC output when the input is at full

scale.

I

_FSis the full-scale ADC phase current.

The ADE7868/ADE7878 compute the difference between the

absolute values of ISUM and the neutral current from the

INWV register, take its absolute value and compare it against

In case of an overcurrent event, if Bit 17 (OI) in the MASK1

IRQ1

register is set, the

interrupt pin is driven low. Immediately,

Bit 17 (OI) in the STATUS1 register and one of Bits[5:3]

(OIPHASE[2:0]) in the PHSTATUS register, which identify

the phase that generated the interrupt, are set. To find the

phase that triggered the interrupt, the PHSTATUS register

is read immediately after reading the STATUS1 register. Next,

Status Bit 17 (OI) in the STATUS1 register and Bits[5:3]

(OIPHASE[2:0]) in the PHSTATUS register are cleared and the

the ISUMLVL threshold. If ISUM − INWV ≤ ISUMLVL ,

then it is assumed that the neutral current is equal to the sum

of the phase currents, and the system functions correctly. If

ISUM − INWV > ISUMLVL , then a tamper situation may

have occurred, and Bit 20 (MISMTCH) in the STATUS1 register

is set to 1. An interrupt attached to the flag can be enabled by

setting Bit 20 (MISMTCH) in the MASK1 register. If enabled,

IRQ1

pin is set to high by writing to the STATUS1 register with

the status bit set to 1. The process is similar with overvoltage

detection.

IRQ1

the

pin is set low when Status Bit MISMTCH is set to 1.

IRQ1

The status bit is cleared and the

pin is set back to high by

Overvoltage and Overcurrent Level Set

writing to the STATUS1 register with Bit 20 (MISMTCH) set to 1.

The content of the overvoltage (OVLVL), and overcurrent,

(OILVL) 24-bit unsigned registers is compared to the absolute

value of the voltage and current channels. The maximum value of

these registers is the maximum value of the HPF outputs:

+5,928,256 (0x5A7540). When the OVLVL or OILVL register is

equal to this value, the overvoltage or overcurrent conditions

are never detected. Writing 0x0 to these registers signifies the

overvoltage or overcurrent conditions are continuously detected,

and the corresponding interrupts are permanently triggered.

If ISUM − INWV ≤ ISUMLVL , then MISMTCH = 0

If ISUM − INWV > ISUMLVL , then MISMTCH = 1

ISUMLVL, the positive threshold used in the process, is a 24-bit

signed register. Because it is used in a comparison with an

absolute value, always set ISUMLVL as a positive number,

somewhere between 0x00000 and 0x7FFFFF. ISUMLVL uses

the same scale of the current ADCs outputs, so writing

+5,928,256 (0x5A7540) to the ISUMLVL register puts the

mismatch detection level at full scale; see the Current Channel

ADC section for details. Writing 0x000000, the default value, or

a negative value, signifies the MISMTCH event is always triggered.

The right value for the application should be written into the

ISUMLVL register after power-up or after a hardware/software

reset to avoid continuously triggering MISMTCH events.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE78xx work on 32-, 16-, or 8-bit words.

Similar to the register presented in Figure 36, OILVL and

OVLVL registers are accessed as 32-bit registers with the eight

MSBs padded with 0s.

Neutral Current Mismatch—ADE7868, ADE7878

Neutral current mismatch is available in the ADE7868 and

ADE7878 only. In 3-phase systems, the neutral current is equal

to the algebraic sum of the phase currents

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE7868/ADE7878 work on 32-, 16-, or 8-bit

words and the DSP works on 28 bits. As presented in Figure 53,

ISUM, the 28-bit signed register, is accessed as a 32-bit register

with the four most significant bits padded with 0s.

I_N(t) = I_A(t) + I_B(t) + I_C(t)

If there is a mismatch between these two quantities, then a

tamper situation may have occurred in the system.

31

28 27

0

0000

28-BIT SIGNED NUMBER

The ADE7868/ADE7878 compute the sum of the phase

currents adding the content of the IAWV, IBWV, and ICWV

registers, and storing the result into the ISUM 28-bit signed

register: I_SUM(t) = I_A(t) + I_B(t) + I_C(t). ISUM is computed every

125 µs (8 kHz frequency), the rate at which the current samples

are available, and Bit 17 (DREADY) in the STATUS0 register is

used to signal when the ISUM register can be read. See the

Digital Signal Processor section for more details on Bit DREADY.

BIT 27 IS A SIGN BIT

Figure 53. The ISUM[27:0] Register is Transmitted As a 32-Bit Word

Similar to the registers presented in Figure 35, the ISUMLVL

register is accessed as a 32-bit register with four most significant

bits padded with 0s and sign extended to 28 bits.

PHASE COMPENSATION

As described in the Current Channel ADC and Voltage Channel

ADC sections, the datapath for both current and voltages is the

same. The phase error between current and voltage signals

introduced by the ADE7854/ADE7858/ADE7868/ADE7878

is negligible. However, the ADE7854/ADE7858/ADE7868/

ADE7878 must work with transducers that may have inherent

To recover I_SUM(t) value from the ISUM register, use the

following expression:

ISUM[27:0]

ADC_MAX

I

_SUM(t) =

×I_FS

where:

Rev. H | Page 39 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

phase errors. For example, a current transformer (CT) with a

phase error of 0.1° to 3° is not uncommon. These phase errors

can vary from part to part, and they must be corrected to

perform accurate power calculations.

acceptable; numbers outside this range are not accepted. If the

current leads the voltage, the result is negative and the absolute

value is written into the PHCAL registers. If the current lags

the voltage, the result is positive and 512 is added to the result

before writing it into xPHCAL.

The errors associated with phase mismatch are particularly

noticeable at low power factors. The ADE78xx provides a means

of digitally calibrating these small phase errors. The ADE78xx

allows a small time delay or time advance to be introduced into

the signal processing chain to compensate for the small phase

errors.

APHCAL,

BPHCAL, or

CPHCAL =

(8)





x

,x ≤ 0









phase _resolution

x



+ 512,x > 0









phase _resolution

The phase calibration registers (APHCAL, BPHCAL, and

CPHCAL) are 10-bit registers that can vary the time advance

in the voltage channel signal path from −374.0 µs to +61.5 μs.

Negative values written to the PHCAL registers represent a time

advance whereas positive values represent a time delay. One LSB

is equivalent to 0.976 µs of time delay or time advance (clock

rate of 1.024 MHz). With a line frequency of 60 Hz, this gives

a phase resolution of 0.0211° (360° × 60 Hz/1.024 MHz) at the

fundamental. This corresponds to a total correction range of

−8.079° to +1.329° at 60 Hz. At 50 Hz, the correction range is

−6.732° to +1.107° and the resolution is 0.0176° (360° × 50 Hz/

1.024 MHz).

Figure 55 illustrates how the phase compensation is used to remove

x = −1° phase lead in IA of the current channel from the external

current transducer (equivalent of 55.5 µs for 50 Hz systems). To

cancel the lead (1°) in the current channel of Phase A, a phase

lead must be introduced into the corresponding voltage channel.

Using Equation 8, APHCAL is 57 least significant bits, rounded

up from 56.8. The phase lead is achieved by introducing a time

delay of 55.73 µs into the Phase A current.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE78xx work on 32-, 16-, or 8-bit words.

As shown in Figure 54, APHCAL, BPHCAL, and CPHCAL

10-bit registers are accessed as 16-bit registers with the six MSBs

padded with 0s.

Given a phase error of x degrees, measured using the phase

voltage as the reference, the corresponding LSBs are computed

dividing x by the phase resolution (0.0211°/LSB for 60 Hz and

0.0176°/LSB for 50 Hz). Results between −383 and +63 only are

15

10

9

0

0000 00

xPHCAL

Figure 54. xPHCAL Registers Communicated As 16-Bit Registers

IAP

IA

IAN

PGA1

ADC

PHASE

CALIBRATION

APHCAL = 57

VAP

VA

VN

PGA3

1°

IA

PHASE COMPENSATION

ACHIEVED DELAYING

IA BY 56µs

VA

50Hz

Figure 55. Phase Calibration on Voltage Channels

Rev. H | Page 40 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

The drift curve on any particular IC can be matched with either

of these sample curves. The general relationship between the

absolute value of the voltage reference at a particular endpoint

temperature and the temperature coefficient for that region of

the curve is explained by the following two equations:

REFERENCE CIRCUIT

The nominal reference voltage at the REF_IN/OUTpin is 1.2 V. This

is the reference voltage for the ADCs in the ADE7854/

ADE7858/ADE7868/ADE7878. Use a typical external reference

voltage of 1.2 V to overdrive the REF_IN/OUTpin. The temperature

coefficient of the internal voltage reference is calculated based

on the endpoint method. To calculate the drift over

temperature, the values of the voltage reference at endpoints

(−40°C and +85°C) are measured and compared to the

reference value at 25°C, which in turn provides the slope of the

temperature coefficient curve. Figure 56 is a typical

α_c

(

− 40°C −25°C

)













V

_{REF (−40°C)}= V_{REF (+25°C)}

×

1+

10⁶

α_h

(

85°C −25°C

)









V_{REF (85°C)}= V_{REF (25°C)}

×

1+

10⁶





where α_cand α_hare cold and hot temperature coefficients,

respectively, calculated by

representation of the drift over temperature. It contains two

curves: Curve X and Curve Y, which are typical representations

of two possible curvatures that are observed over the entire

specified temperature range.

V_REF_(−40°C)−V_REF

(+25°C)

V_REF

(+25°C)

× 10⁶ppm/°C

α_c=

(

−40°C −25°C

)

–40°C

A'

+85°C

C'

V_REF_(85°C)−V_REF

(25°C)

CURVE Y

CURVE X

V_REF

+25°C

B

(25°C)

α_h=

× 10⁶ppm/°C

(

85°C −25°C

)

As the sign of cold and hot temperature coefficients can vary

from one IC to another, the typical drift is specified for the

whole range with a plus-minus sign( ). To find the typical,

minimum and maximum temperature coefficients, as listed in

the Specifications section, data based on the end-point method

is collected on ICs spread out over different lots. The minimum

and maximum temperature coefficents denote that the drift of

any particular IC will be within those limits, over the specified

temperature range, with reference to 25°C. See Figure 57 and

Figure 58 for the device-to-device variation of the drift.

A

C

–40°C

+85°C

TEMPERATURE (°C)

Figure 56. Internal Voltage Reference Temperature Drift

Figure 56 shows that independent consideration of two regions

is necessary for accurate analysis of the drift over temperature,

as follows:

•

Considering the region between Point A and Point B in

Curve X, the reference value increases with an increase in

temperature; thus, the curve has a positive slope from A to

B. This results in a positive temperature coefficient in this

region.

Considering the region between Point B and Point C in

Curve X, the slope of the curve is negative because the

voltage reference decreases with an increase in

temperature; thus, this region of the curve has a negative

temperature coefficient.

Based on similar logic, Curve Y has a negative temperature

coefficient between Point A’ and PointB and a positive

temperature coefficient between Point B and PointC’.

–50 –45 –40 –35 –30 –5 –20 –15 –10 –5

0

5 10 15 20 25 30 35 40 45 50

COLD TEMPERATURE COEFFICIENT (ppm/°C)

Figure 57. Histogram of the Reference Drift from −40°C to +25°C

Rev. H | Page 41 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

memory RAM are initialized at 0, their default values, and they

can be read/written without any restriction. The run register,

used to start and stop the DSP, is cleared to 0x0000. The run

register needs to be written with 0x0001 for the DSP to start

code execution.

To protect the integrity of the data stored in the data memory

RAM of the DSP (addresses between 0x4380 and 0x43BE),

a write protection mechanism is available. By default, the

protection is disabled and registers placed between 0x4380 and

0x43BE can be written without restriction. When the protection

is enabled, no writes to these registers is allowed. Registers can

be always read, without restriction, independent of the write

protection state.

–50 –45 –40 –35 –30 –5 –20 –15 –10 –5

0

5 10 15 20 25 30 35 40 45 50

HOT TEMPERATURE COEFFICIENT (ppm/°C)

To enable the protection, write 0xAD to an internal 8-bit

register located at Address 0xE7FE, followed by a write of 0x80

to an internal 8-bit register located at Address 0xE7E3.

Figure 58. Histogram of the Reference Drift from 25°C to 85°C

Because the reference is used for all ADCs, any x% drift in the

reference results in a 2x% deviation of the meter accuracy. The

reference drift resulting from temperature changes is usually very

small and, typically, much smaller than the drift of other

components on a meter.

It is recommended to enable the write protection after the

registers have been initialized. If any data memory RAM based

register needs to be changed, simply disable the protection,

change the value and then re-enable the protection. There is

no need to stop the DSP to change these registers.

The ADE7854/ADE7858/ADE7868/ADE7878 use the internal

voltage reference when Bit 0 (EXTREFEN) in the CONFIG2

register is cleared to 0 (the default value); the external voltage

reference is used when the bit is set to 1. Set the CONFIG2 register

during the PSM0 mode; its value is maintained during the PSM1,

PSM2, and PSM3 power modes.

To disable the protection, write 0xAD to an internal 8-bit

register located at Address 0xE7FE, followed by a write of 0x00

to an internal 8-bit register located at Address 0xE7E3.

The recommended procedure to initialize the ADE7854/

ADE7858/ADE7868/ADE7878 registers at power up is as

follows:

DIGITAL SIGNAL PROCESSOR

The ADE7854/ADE7858/ADE7868/ADE7878 contain a fixed

function digital signal processor (DSP) that computes all powers

and rms values. It contains program memory ROM and data

memory RAM.



Initialize the AIGAIN, BIGAIN, CIGAIN, and NIGAIN

registers.



Start the DSP by setting run = 1.

The program used for the power and rms computations is

stored in the program memory ROM and the processor executes

it every 8 kHz. The end of the computations is signaled by

setting Bit 17 (DREADY) to 1 in the STATUS0 register. An

interrupt attached to this flag can be enabled by setting Bit 17

Initialize all the other data memory RAM registers. Write

the last register in the queue three times to ensure its

value was written into the RAM. Initialize all of the other

ADE7854/ADE7858/ADE7868/ADE7878 registers with the

exception of the CFMODE register.

IRQ0

(DREADY) in the MASK0 register. If enabled, the

set low and Status Bit DREADY is set to 1 at the end of the

IRQ0

pin is



Read the energy registers xWATTHR, xFWATTHR,

xVARHR, xFVARHR, and xVAHR to erase their content

and start energy accumulation from a known state.

computations. The status bit is cleared and the

pin is set

to high by writing to the STATUS0 register with Bit 17 (DREADY)

set to 1.

Clear Bit 9 (CF1DIS), Bit 10 (CF2DIS), and Bit 11

(CF3DIS) in the CFMODE register to enable pulses at

the CF1, CF2, and CF3 pins. Do this initialization last,

so no spurious pulses are generated while the ADE7854/

ADE7858/ADE7868/ADE7878 are initialized.

The registers used by the DSP are located in the data memory

RAM, at addresses between 0x4380 and 0x43BE. The width of

this memory is 28 bits. Within the DSP core, the DSP contains a

two stage pipeline. This means that when a single register needs

to be initialized, two more writes are required to ensure the

value has been written into RAM, and if two or more registers

need to be initialized, the last register must be written two more

times to ensure the value has been written into RAM.



Enable the write protection by writing 0xAD to an internal

8-bit register located at Address 0xE7FE, followed by a write of

0x80 to an internal 8-bit register located at Address 0xE7E3.



Read back all data memory RAM registers to ensure they

were initialized with the desired values.

As explained in the Power-Up Procedure section, at power-up

or after a hardware or software reset, the DSP is in idle mode.

No instruction is executed. All the registers located in the data

In the remote case that one or more registers are not initia-

lized correctly, disable the protection by writing 0xAD to

Rev. H | Page 42 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

∞

an internal 8-bit register located at Address 0xE7FE, followed

f (t) =

F

2 sin

(

kωt + γ_k

)

(11)

∑

k

by a write of 0x00 to an internal 8-bit register located at

Address 0xE7E3. Reinitialize the registers. Write the last

register in the queue three times. Enable the write protec-

tion by writing 0xAD to an internal 8-bit register located

at Address 0xE7FE, followed by a write of 0x80 to an internal

8-bit register located at Address 0xE7E3.

k=1

Then

∞

f ²(t) = F²− F²cos(2kωt + 2γ ) +

∑

k=1

k

k=1

∞

(12)

+ 2 2× F × F sin

(

kωt + γ_k

)

×sin

(

mωt + γ_m

)

∑

m

k

k,m=1

k≠m

There is no obvious reason to stop the DSP if the ADE78xx is

maintained in PSM0 normal mode. All ADE78xx registers,

including ones located in the data memory RAM, can be

modified without stopping the DSP. However, to stop the DSP,

0x0000 has to be written into run register. To restart the DSP,

one of the following procedures must be followed:

After the LPF and the execution of the square root, the rms

value of f(t) is obtained by

∞

F =

F²

(13)

∑

k

k=1

•

If the ADE7854/ADE7858/ADE7868/ADE7878 registers

located in the data memory RAM have not been modified,

write 0x0001 into the run register to start the DSP.

If the ADE7854/ADE7858/ADE7868/ADE7878 registers

located in the data memory RAM have to be modified, first

execute a software or a hardware reset, and then follow the

recommended procedure to initialize the registers at power

up.

The rms calculation based on this method is simultaneously

processed on all seven analog input channels. Each result is

available in the 24-bit registers: AIRMS, BIRMS, CIRMS,

AVRMS, BVRMS, CVRMS, and NIRMS (NIRMS is available

on the ADE7868 and ADE7878 only).

•

The second method computes the absolute value of the input

signal and then filters it to extract its dc component. It computes

the absolute mean value of the input. If the input signal in

Equation 12 has a fundamental component only, its average

value is

As mentioned in the Power Management section, when the

ADE7854/ADE7858/ADE7868/ADE7878 switch out of PSM0

power mode, it is recommended to stop the DSP by writing

0x0000 into the run register (see Figure 11 and Table 12 for

the recommended actions when changing power modes).

^T₂







T

1

T

F_DC

=

2 × F₁×sin(ωt)dt − 2 × F₁×sin(ωt)dt

∫



T

⁰







2

ROOT MEAN SQUARE MEASUREMENT

2

π

Root mean square (rms) is a measurement of the magnitude of

an ac signal. Its definition can be both practical and mathematical.

Defined practically, the rms value assigned to an ac signal is the

amount of dc required to produce an equivalent amount of

power in the load. Mathematically, the rms value of a conti-

nuous signal f(t) is defined as

F_DC

=

×

2 ×F₁

The calculation based on this method is simultaneously processed

only on the three phase currents. Each result is available in the

20-bit registers, which are available on the ADE7868 and

ADE7878 only: AIMAV, BMAV, and CMAV. Note that the

proportionality between mav and rms values is maintained for

the fundamental components only. If harmonics are present in the

current channel, the mean absolute value is no longer

proportional to rms.

1

t

F rms =

₀^tf ²

(

t

)

dt

(9)

∫

For time sampling signals, rms calculation involves squaring the

signal, taking the average, and obtaining the square root.

Current RMS Calculation

N

1

N

F rms =

f ²

[n

]

(10)

This section presents the first approach to compute the rms

values of all phase and neutral currents.

∑

N=1

Equation 10 implies that for signals containing harmonics, the

rms calculation contains the contribution of all harmonics, not

only the fundamental. The ADE78xx uses two different methods

to calculate rms values. The first one is very accurate and is active

only in PSM0 mode. The second one is less accurate, uses the

estimation of the mean absolute value (mav) measurement, is

active in PSM0 and PSM1 modes, and is available for the

ADE7868 and ADE7878 only.

Figure 59 shows the detail of the signal processing chain for the

rms calculation on one of the phases of the current channel.

The current channel rms value is processed from the samples

used in the current channel. The current rms values are signed

24-bit values and they are stored into the AIRMS, BIRMS, CIRMS,

and NIRMS (ADE7868/ADE7878 only) registers. The update

rate of the current rms measurement is 8 kHz.

With the specified full-scale analog input signal of 0.5 V, the

ADC produces an output code that is approximately 5,928,256.

The equivalent rms value of a full-scale sinusoidal signal is

4,191,910 (0x3FF6A6), independent of the line frequency. If

The first method is to low-pass filter the square of the input

signal (LPF) and take the square root of the result (see Figure 59).

Rev. H | Page 43 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

the integrator is enabled, that is, when Bit 0 (INTEN) in the

CONFIG register is set to 1, the equivalent rms value of a full-

scale sinusoidal signal at 50 Hz is 4,191,910 (0x3FF6A6) and at

60 Hz is 3,493,258 (0x354D8A).

power-up and DSP reset cases, it would typically take about

1.2 seconds for a FS/1000 signal to be settled.

Table 13. Settling Time for I rms Measurement

Integrator Status 50 Hz Input signals 60 Hz Input signals

The accuracy of the current rms is typically 0.1% error from

the full-scale input down to 1/1000 of the full-scale input when

PGA = 1. Additionally, this measurement has a bandwidth of

2 kHz. It is recommended to read the rms registers synchronous

Integrator Off

Integrator On

440 ms

550 ms

440 ms

500 ms

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE78xx work on 32-, 16-, or 8-bit words.

Similar to the register presented in Figure 36, the AIRMS,

BIRMS, CIRMS, and NIRMS (ADE7868 and ADE7878 only)

24-bit signed registers are accessed as 32-bit registers with the

eight MSBs padded with 0s.

IRQ1

to the voltage zero crossings to ensure stability. The

inter-

rupt can be used to indicate when a zero crossing has occurred

(see the Interrupts section). Table 13 shows the settling time for

the I rms measurement, which is the time it takes for the rms

register to reflect the value at the input to the current channel

when starting from 0 to full scale. However, during the chip

xIRMSOS[23:0]

7

2

CURRENT SIGNAL FROM

HPF OR INTEGRATOR

2

x

xIRMS[23:0]

√

LPF

(IF ENABLED)

0x5A7540 =

5,928,256

0V

0xA58AC0 =

–5,928,256

Figure 59. Current RMS Signal Processing

Rev. H | Page 44 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

212000

Current RMS Offset Compensation

211500

211000

210500

210000

209500

209000

208500

208000

207500

The ADE7854/ADE7858/ADE7868/ADE7878 incorporate a

current rms offset compensation register for each phase:

AIRMSOS, BIRMSOS, CIRMSOS registers, and the NIRMSOS

register for ADE7868 and ADE7878 only. These are 24-bit

signed registers that are used to remove offsets in the current

rms calculations. An offset can exist in the rms calculation due

to input noises that are integrated in the dc component of I²(t).

The current rms offset register is multiplied by 128 and added

to the squared current rms before the square root is executed.

Assuming that the maximum value from the current rms

calculation is 4,191,910 with full-scale ac inputs (50 Hz), one LSB of

207000

45

50

55

60

65

the current rms offset represents 0.00037% (( 4191²128 /4191

− 1) × 100) of the rms measurement at 60 dB down from full

scale. Conduct offset calibration at low current; avoid using

currents equal to zero for this purpose.

FREQUENCY (Hz)

Figure 61. xIMAV Register Values at Full Scale, 45 Hz to 65 Hz Line

Frequencies

The mav values of full-scale sinusoidal signals of 50 Hz and

60 Hz are 209,686 and 210,921, respectively. As seen in Figure 61,

there is a 1.25% variation between the mav estimate at 45 Hz

and the one at 65 Hz for full-scale sinusoidal inputs. The accuracy

of the current mav is typically 0.5% error from the full-scale

input down to 1/100 of the full-scale input. Additionally, this

measurement has a bandwidth of 2 kHz. The settling time for

the current mav measurement, that is the time it takes for the

mav register to reflect the value at the input to the current

channel within 0.5% error, is 500 ms. However, during the first

measurement after entering this mode, it takes a longer time to

settle to the correct value.

I rms  I rms₀²128IRMSOS

(14)

where I rms₀is the rms measurement without offset correction.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE78xx work on 32-, 16-, or 8-bit words

and the DSP works on 28 bits. Similar to the register presented

in Figure 35, the AIRMSOS, BIRMSOS, CIRMSOS, and

NIRMSOS (ADE7868/ADE7878 only) 24-bit signed registers

are accessed as 32-bit registers with four MSBs padded with 0s

and sign extended to 28 bits.

Current Mean Absolute Value Calculation—ADE7868

and ADE7878 Only

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE7868/ADE7878 work on 32-, 16-, or

8-bit words. As presented in Figure 62, the AIMAV, BIMAV, and

CIMAV 20-bit unsigned registers are accessed as 32-bit registers

with the 12 MSBs padded with 0s.

This section presents the second approach to estimate the rms

values of all phase currents using the mean absolute value (mav)

method. This approach is used in PSM1 mode, which is available

to the ADE7868 and ADE7878 only, to allow energy accumu-

lation based on current rms values when the missing neutral

case demonstrates to be a tamper attack. This datapath is active

also in PSM0 mode to allow for its gain calibration. The gain is

used in the external microprocessor during PSM1 mode. The

mav value of the neutral current is not computed using this

method. Figure 60 shows the details of the signal processing

chain for the mav calculation on one of the phases of the current

channel.

31

20 19

0

0000 0000 0000

20-BIT UNSIGNED NUMBER

Figure 62. xIMAV Registers Transmitted as 32-Bit Registers

Current MAV Gain and Offset Compensation

The current rms values stored in the AIMAV, BIMAV, and

CIMAV registers can be calibrated using gain and offset

coefficients corresponding to each phase. It is recommended to

calculate the gains in PSM0 mode by supplying the ADE7868/

ADE7878 with nominal currents. The offsets can be estimated

by supplying the ADE7868/ADE7878 with low currents, usually

equal to the minimum value at which the accuracy is required.

Every time the external microcontroller reads the AIMAV,

CURRENT SIGNAL

COMING FROM ADC

xIMAV[23:0]

|X|

HPF

LPF

Figure 60. Current MAV Signal Processing for PSM1 Mode

The current channel mav value is processed from the samples

used in the current channel waveform sampling mode. The

samples are passed through a high-pass filter to eliminate the

eventual dc offsets introduced by the ADCs and the absolute

values are computed. The outputs of this block are then filtered

to obtain the average. The current mav values are unsigned 20-bit

values and they are stored in the AIMAV, BIMAV, and CIMAV

registers. The update rate of this mav measurement is 8 kHz.

BIMAV, and CIMAV registers, it uses these coefficients stored

in its memory to correct them.

Voltage Channel RMS Calculation

Figure 63 shows the detail of the signal processing chain for the

rms calculation on one of the phases of the voltage channel. The

voltage channel rms value is processed from the samples used in

the voltage channel. The voltage rms values are signed 24-bit

Rev. H | Page 45 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

values and they are stored into the Registers AVRMS, BVRMS, and

CVRMS. The update rate of the current rms measurement is 8 kHz.

IRQ1

interrupt can be used to indicate

when a zero crossing has occurred (see the Interrupts section).

to ensure stability. The

With the specified full-scale analog input signal of 0.5 V, the

ADC produces an output code that is approximately 5,928,256.

The equivalent rms value of a full-scale sinusoidal signal is

4,191,910 (0x3FF6A6), independent of the line frequency.

The settling time for the V rms measurement is 440 ms for both

50 Hz and 60 Hz input signals. The V rms measurement settling

time is the time it takes for the rms register to reflect the value

at the input to the voltage channel when starting from 0.

The accuracy of the voltage rms is typically 0.1% error from the

full-scale input down to 1/1000 of the full-scale input. Additionally,

this measurement has a bandwidth of 2 kHz. It is recommended

to read the rms registers synchronous to the voltage zero crossings

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE78xx work on 32-, 16-, or 8-bit words.

Similar to the register presented in Figure 36, the AVRMS,

BVRMS, and CVRMS 24-bit signed registers are accessed as

32-bit registers with the eight MSBs padded with 0s.

xVRMSOS[23:0]

7

2

VOLTAGE SIGNAL

2

x

xVRMS[23:0]

√

FROM HPF

LPF

0x5A7540 =

5,928,256

0V

0xA58AC0 =

–5,928,256

Figure 63. Voltage RMS Signal Processing

Rev. H | Page 46 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Voltage RMS Offset Compensation

ac system is supplied by a voltage, v(t), and consumes the current,

i(t), and each of them contains harmonics, then

The ADE78xx incorporates voltage rms offset compensation

registers for each phase: AVRMSOS, BVRMSOS, and CVRMSOS.

These are 24-bit signed registers used to remove offsets in the

voltage rms calculations. An offset can exist in the rms calculation

due to input noises that are integrated in the dc component of

V²(t). The voltage rms offset register is multiplied by 128 and

added to the squared current rms before the square root is

executed. Assuming that the maximum value from the voltage

rms calculation is 4,191,910 with full-scale ac inputs (50 Hz), one

LSB of the voltage rms offset represents 0.00037%

v(t)  ^V 2 sin (kωt + φ_k)

(16)



k

k1



i(t) 

I

2 sin



kωt  γ_k





k

k1

where:

V_k, I_kare rms voltage and current, respectively, of each

harmonic.

φ_k, γ_kare the phase delays of each harmonic.

(( 4191²128 /4191 − 1) × 100) of the rms measurement at

60 dB down from full scale. Conduct offset calibration at low

current; avoid using voltages equal to zero for this purpose.

The instantaneous power in an ac system is

p(t) = v(t) × i(t) = ^V I cos(φ_k– γ_k) − ^V I cos(2kωt + φ_k+ γ_k) +



k1

k

k k

k1

^V I {cos[(k − m)ωt + φ_k– γ_m] – cos[(k + m)ωt + φ_k+ γ_m]}

V rms  V rms₀²128VRMSOS

(15)



m

k

k, m1

km

where V rms₀is the rms measurement without offset correction.

(17)

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE78xx work on 32-, 16-, or 8-bit words

and the DSP works on 28 bits. Similar to registers presented in

Figure 35, the AVRMSOS, BVRMSOS, and CVRMSOS 24-bit

registers are accessed as 32-bit registers with the four most

significant bits padded with 0s and sign extended to 28 bits.

The average power over an integral number of line cycles (n) is

given by the expression in Equation 18.

nT

1

nT

P =



p t



dt  ^V I cos(φ_k– γ_k)

(18)





k

k1

0

where:

T is the line cycle period.

P is referred to as the total active or total real power.

ACTIVE POWER CALCULATION

The ADE7854/ADE7858/ADE7868/ADE7878 compute the

total active power on every phase. Total active power considers

in its calculation all fundamental and harmonic components of

the voltages and currents. In addition, the ADE7878 computes

the fundamental active power, the power determined only by

the fundamental components of the voltages and currents.

Note that the total active power is equal to the dc component of

the instantaneous power signal p(t) in Equation 17, that is,

^V I cos(φ_k– γ_k)



k

k1

This is the expression used to calculate the total active power in

the ADE78xx for each phase. The expression of fundamental active

power is obtained from Equation 18 with k = 1, as follows:

Total Active Power Calculation

Electrical power is defined as the rate of energy flow from source

to load, and it is given by the product of the voltage and current

waveforms. The resulting waveform is called the instantaneous

power signal, and it is equal to the rate of energy flow at every

instant of time. The unit of power is the watt or joules/sec. If an

FP = V₁I₁cos(φ₁– γ₁)

(19)

Figure 64 shows how the ADE78xx computes the total active

power on each phase. First, it multiplies the current and voltage

signals in each phase. Next, it extracts the dc component of the

instantaneous power signal in each phase (A, B, and C) using

LPF2, the low-pass filter.

HPFDIS

[23:0]

DIGITAL

INTEGRATOR

AIGAIN

AVGAIN

AWGAIN

AWATTOS

I

A

HPF

HPFDIS

[23:0]

INSTANTANEOUS

PHASE A ACTIVE

POWER

APHCAL

LPF

V

A

AWATT

HPF

4

2

DIGITAL SIGNAL PROCESSOR

Figure 64. Total Active Power Datapath

Rev. H | Page 47 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

If the phase currents and voltages contain only the fundamental

component, are in phase (that is φ₁= γ₁= 0), and they correspond

to full-scale ADC inputs, then multiplying them results in an

instantaneous power signal that has a dc component, V₁× I₁,

and a sinusoidal component, V₁× I₁cos(2ωt); Figure 65 shows

the corresponding waveforms.

PMAX = 33,516,139; it is the instantaneous power computed

when the ADC inputs are at full scale and in phase.

The xWATT[23:0] waveform registers can be accessed using

various serial ports. Refer to the Waveform Sampling Mode

section for more details.

Fundamental Active Power Calculation—ADE7878 Only

INSTANTANEOUS

p(t)= V rms × I rms – V rms × I rms × cos(2ωt)

POWER SIGNAL

The ADE7878 computes the fundamental active power using

a proprietary algorithm that requires some initializations function

of the frequency of the network and its nominal voltage measured

in the voltage channel. Bit 14 (SELFREQ) in the COMPMODE

register must be set according to the frequency of the network in

which the ADE7878 is connected. If the network frequency is

50 Hz, clear this bit to 0 (the default value). If the network fre-

quency is 60 Hz, set this bit to 1. In addition, initialize the VLEVEL

24-bit signed register with a positive value based on the

following expression:

0x3FED4D6

67,032,278

INSTANTANEOUS

ACTIVE POWER

SIGNAL: V rms × I rms

V rms × I rms

0x1FF6A6B =

33,516,139

0x000 0000

i(t) = √2 × I rms × sin(ωt)

v(t) = √2 × V rms × sin(ωt)

V_FS

VLEVEL =

× 491,520

(21)

V_n

where:

_FSis the rms value of the phase voltages when the ADC inputs

are at full scale.

Figure 65. Active Power Calculation

V

Because LPF2 does not have an ideal brick wall frequency

response (see Figure 66), the active power signal has some

ripple due to the instantaneous power signal. This ripple is

sinusoidal and has a frequency equal to twice the line frequency.

Because the ripple is sinusoidal in nature, it is removed when

the active power signal is integrated over time to calculate the

energy.

V_nis the rms nominal value of the phase voltage.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE7878 work on 32-, 16-, or 8-bit words

and the DSP works on 28 bits. Similar to the registers presented

in Figure 35, the VLEVEL 24-bit signed register is accessed as a

32-bit register with four most significant bits padded with 0s

and sign extended to 28 bits.

0

Table 14 presents the settling time for the fundamental active

power measurement.

–5

–10

–15

–20

–25

Table 14. Settling Time for Fundamental Active Power

Input Signals

63% Full Scale

100% Full Scale

375 ms

875 ms

Active Power Gain Calibration

Note that the average active power result from the LPF2 output

in each phase can be scaled by 100% by writing to the phase’s

watt gain 24-bit register (AWGAIN, BWGAIN, CWGAIN,

AFWGAIN, BFWGAIN, or CFWGAIN). The xWGAIN

registers are placed in each phase of the total active power

datapath, and the xFWGAIN (available for the ADE7878 only)

registers are placed in each phase of the fundamental active

power datapath. The watt gain registers are twos complement,

signed registers and have a resolution of 2⁻²³/LSB. Equation 22

describes mathematically the function of the watt gain registers.

0.1

1

3

10

FREQUENCY (Hz)

Figure 66. Frequency Response of the LPF Used

to Filter Instantaneous Power in Each Phase

The ADE7854/ADE7858/ADE7868/ADE7878 store the

instantaneous total phase active powers into the AWAT T,

BWAT T, and CWATT registers. Their expression is

∞

V_k

I_k

1

xWATT =

×

cos(φ_k– γ_k) × PMAX ×

(20)

∑

2⁴

_k=1V_FSI_FS

Average Power Data =

where:

(22)

Watt Gain Register







LPF2 Output × 1 +



2²³

V_FS, I_FSare the rms values of the phase voltage and current when

the ADC inputs are at full scale.





Rev. H | Page 48 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

The output is scaled by −50% by writing 0xC00000 to the watt

gain registers, and it is increased by +50% by writing 0x400000

to them. These registers are used to calibrate the active power

(or energy) calculation in the ADE7854/ADE7858/ADE7868/

ADE7878for each phase.

Calculation section, the active energy accumulation is performed

in two stages. Every time a sign change is detected in the energy

accumulation at the end of the first stage, that is, after the energy

accumulated into the internal accumulator reaches the WTHR

register threshold, a dedicated interrupt is triggered. The sign of

each phase active power can be read in the PHSIGN register.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE7854/ADE7858/ADE7868/ADE7878

work on 32-, 16-, or 8-bit words, and the DSP works on 28 bits.

Similar to registers presented in Figure 35, AWGAIN, BWGAIN,

CWGAIN, AFWGAIN, BFWGAIN, and CFWGAIN 24-bit

signed registers are accessed as 32-bit registers with the four

MSBs padded with 0s and sign extended to 28 bits.

Bit 6 (REVAPSEL) in the ACCMODE register sets the type

of active power being monitored. When REVAPSEL is 0,

the default value, the total active power is monitored. When

REVAPSEL is 1, the fundamental active power is monitored.

Bits[8:6] (REVAPC, REVAPB, and REVAPA, respectively) in the

STATUS0 register are set when a sign change occurs in the

power selected by Bit 6 (REVAPSEL) in the ACCMODE

register.

Active Power Offset Calibration

The ADE7854/ADE7858/ADE7868/ADE7878 incorporate a

watt offset 24-bit register on each phase and on each active

power. The AWAT TOS, BWATTOS, and CWATTOS registers

compensate the offsets in the total active power calculations,

and the AFWATTOS, BFWATTOS, and CFWATTOS registers

compensate offsets in the fundamental active power calculations.

These are signed twos complement, 24-bit registers that are

used to remove offsets in the active power calculations. An

offset can exist in the power calculation due to crosstalk between

channels on the PCB or in the chip itself. One LSB in the active

power offset register is equivalent to 1 LSB in the active power

multiplier output. With full-scale current and voltage inputs,

the LPF2 output is PMAX = 33,516,139. At −80 dB down from

the full scale (active power scaled down 10⁴times), one LSB of

the active power offset register represents 0.0298% of PMAX.

Bits[2:0] (CWSIGN, BWSIGN, and AWSIGN, respectively) in

the PHSIGN register are set simultaneously with the REVAPC,

REVAPB, and REVAPA bits. They indicate the sign of the power.

When they are 0, the corresponding power is positive. When

they are 1, the corresponding power is negative.

Bit REVAPx of STATUS0 and Bit xWSIGN in the PHSIGN

register refer to the total active power of Phase x, the power type

being selected by Bit 6 (REVAPSEL) in the ACCMODE register.

Interrupts attached to Bits[8:6] (REVAPC, REVAPB, and REVAPA,

respectively) in the STATUS0 register can be enabled by setting

IRQ0

Bits[8:6] in the MASK0 register. If enabled, the

pin is set

low, and the status bit is set to 1 whenever a change of sign occurs.

To find the phase that triggered the interrupt, the PHSIGN register

is read immediately after reading the STATUS0 register. Next, the

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE7854/ADE7858/ADE7868/ADE7878

work on 32-, 16-, or 8-bit words and the DSP works on 28 bits.

Similar to registers presented in Figure 35, the AWATTOS,

BWATTOS, CWATTOS, AFWATTOS, BFWATTOS, and

CFWATTOS 24-bit signed registers are accessed as 32-bit

registers with the four MSBs padded with 0s and sign extended

to 28 bits.

IRQ0

status bit is cleared and the

pin is returned to high by writing

to the STATUS0 register with the corresponding bit set to 1.

Active Energy Calculation

As previously stated, power is defined as the rate of energy flow.

This relationship can be expressed mathematically as

dEnergy

Power =

(23)

dt

Conversely, energy is given as the integral of power, as follows:

Energy = p dt

(24)

Sign of Active Power Calculation

The average active power is a signed calculation. If the phase

difference between the current and voltage waveform is more

than 90°, the average power becomes negative. Negative power

indicates that energy is being injected back on the grid. The

ADE78xx has sign detection circuitry for active power

t

( )

∫

Total and fundamental active energy accumulations are always

signed operations. Negative energy is subtracted from the active

energy contents.

calculations. It can monitor the total active powers or the

fundamental active powers. As described in the Active Energy

Rev. H | Page 49 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

HPFDIS

[23:0]

DIGITAL

INTEGRATOR

AIGAIN

REVAPA BIT IN

STATUS0[31:0]

IA

HPF

AWGAIN

AWATTOS

AWATTHR[31:0]

HPFDIS

[23:0]

APHCAL

AVGAIN

ACCUMULATOR

LPF2

32-BIT

REGISTER

VA

HPF

WTHR[47:0]

AWATT

4

2

DIGITAL SIGNAL PROCESSOR

Figure 67. Total Active Energy Accumulation

The ADE7854/ADE7858/ADE7868/ADE7878 achieve the

integration of the active power signal in two stages (see Figure 67).

The process is identical for both total and fundamental active

powers. The first stage is accomplished inside the DSP: every

125 µs (8 kHz frequency) the instantaneous phase total or funda-

mental active power is accumulated into an internal register.

When a threshold is reached, a pulse is generated at the processor

port, and the threshold is subtracted from the internal register.

The sign of the energy in this moment is considered the sign of

the active power (see Sign of Active Power Calculation section

for details). The second stage is done outside the DSP and consists

of accumulating the pulses generated by the processor into internal

32-bit accumulation registers. The content of these registers is

transferred to watt-hour registers, xWAT THR and xFWATTHR,

when these registers are accessed.

where:

PMAX = 33,516,139 = 0x1FF6A6B as the instantaneous power

computed when the ADC inputs are at full scale.

f_S= 8 kHz, the frequency with which the DSP computes the

instantaneous power.

V_FS, I_FSare the rms values of phase voltages and currents when

the ADC inputs are at full scale.

The maximum value that can be written on WTHR is 2⁴⁷− 1.

The minimum value is 0x0, but it is recommended to write a

number equal to or greater than PMAX. Never use negative

numbers.

WTHR is a 48-bit register. As stated in the Current Waveform

Gain Registers section, the serial ports of the ADE7854/ADE7858/

ADE7868/ADE7878work on 32-, 16-, or 8-bit words. As shown

in Figure 69, the WTHR register is accessed as two 32-bit

registers (WTHR1 and WTHR0), each having eight MSBs

padded with 0s.

WTHR[47:0]

ACTIVE POWER

ACCUMULATION

IN DSP

WTHR[47:0]

47

24 23

0

31

24 23

0

31

0000 0000

24 23

0

0000 0000

24 BIT SIGNED NUMBER

DSP

GENERATED

WTHR1[31:0]

WTHR0[31:0]

PULSES

1 DSP PULSE = 1LSB OF WATTHR[31:0]

Figure 69. WTHR[47:0] Communicated As Two 32-Bit Registers

Figure 68. Active Power Accumulation Inside the DSP

This discrete time accumulation or summation is equivalent to

integration in continuous time following the description in

Equation 26.

Figure 68 explains this process. The WTHR 48-bit signed register

contains the threshold. It is introduced by the user and is common

for all phase total and fundamental active powers. Its value

depends on how much energy is assigned to one LSB of watt-

hour registers. When a derivative of active energy (wh) of [10ⁿ

wh], where n is an integer, is desired as one LSB of the

xWATTHR register, then, the xWATTHR register can be

computed using the following equation:

 ^∞







Energy = p

(

t

)

dt =

p

(

nT

)

× T

(26)

Lim

∑

_T→0

∫

n=0



where:

n is the discrete time sample number.

T is the sample period.

PMAX × f_S×3600 ×10ⁿ

In the ADE7854/ADE7858/ADE7868/ADE7878, the total phase

active powers are accumulated in the AWATTHR, BWATTHR, and

CWAT THR 32-bit signed registers, and the fundamental phase

active powers are accumulated in AFWATTHR, BFWATTHR, and

WTHR =

(25)

V

_FS× I_FS

Rev. H | Page 50 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

CFWATTHR 32-bit signed registers. The active energy register

content can roll over to full-scale negative (0x80000000) and

continue increasing in value when the active power is positive.

Conversely, if the active power is negative, the energy register

underflows to full-scale positive (0x7FFFFFFF) and continues

decreasing in value.

Table 15. Inputs to Watt-Hour Accumulation Registers

CONSEL

AWATTHR

BWATTHR

CWATTHR

00

01

10

VA × IA

VB × IB

0

VB × IB

VC × IC

VB = −VA − VC

VB × IB

11

VA × IA

VC × IC

Bit 0 (AEHF) in the STATUS0 register is set when Bit 30 of

one of the xWATTHR registers changes, signifying one of these

registers is half full. If the active power is positive, the watt-hour

register becomes half full when it increments from 0x3FFF FFFF to

0x4000 0000. If the active power is negative, the watt-hour

register becomes half full when it decrements from 0xC000

0000 to 0xBFFF FFFF. Similarly, Bit 1 (FAEHF) in STATUS0

register, is set when Bit 30 of one of the xFWATTHR registers

changes, signifying one of these registers is half full.

VB = −VA

Depending on the polyphase meter service, choose the appro-

priate formula to calculate the active energy. The American

ANSI C12.10 standard defines the different configurations of

the meter. Table 16 describes which mode to choose in these

various configurations.

Table 16. Meter Form Configuration

ANSI Meter Form

Configuration

3-wire delta

4-wire wye

4-wire delta

4-wire wye

CONSEL

Setting Bits[1:0] in the MASK0 register enable the FAEHF and

5S/13S

6S/14S

8S/15S

9S/16S

01

10

11

00

IRQ0

AEHF interrupts, respectively. If enabled, the

pin is set

low and the status bit is set to 1 whenever one of the energy

registers, xWATTHR (for the AEHF interrupt) or xFWATTHR

(for the FAEHF interrupt), become half full. The status bit is

Bits[1:0] (WATTACC[1:0]) in the ACCMODE register determine

how the CF frequency output can be generated as a function of

the total and fundamental active powers. Whereas the watt-hour

accumulation registers accumulate the active power in a signed

format, the frequency output can be generated in signed mode

or in absolute mode as a function of the WATTACC[1:0] bits.

See the Energy-to-Frequency Conversion section for details.

IRQ0

cleared and the

pin is set to logic high by writing to the

STATUS0 register with the corresponding bit set to 1.

Setting Bit 6 (RSTREAD) of the LCYCMODE register enables a

read-with-reset for all watt-hour accumulation registers, that is,

the registers are reset to 0 after a read operation.

Integration Time Under Steady Load

The discrete time sample period (T) for the accumulation register

is 125 µs (8 kHz frequency). With full-scale sinusoidal signals

on the analog inputs and the watt gain registers set to 0x00000, the

average word value from each LPF2 is PMAX = 33,516,139 =

0x1FF6A6B. If the WTHR register threshold is set at the PMAX

level, this means the DSP generates a pulse that is added at watt-

hour registers every 125 µs.

Line Cycle Active Energy Accumulation Mode

In line cycle energy accumulation mode, the energy accumula-

tion is synchronized to the voltage channel zero crossings such

that active energy is accumulated over an integral number of

half line cycles. The advantage of summing the active energy

over an integer number of line cycles is that the sinusoidal compo-

nent in the active energy is reduced to 0. This eliminates any

ripple in the energy calculation and allows the energy to be

accumulated accurately over a shorter time. By using the line

cycle energy accumulation mode, the energy calibration can be

greatly simplified, and the time required to calibrate the meter

can be significantly reduced. In line cycle energy accumulation

mode, the ADE7854/ADE7858/ADE7868/ADE7878 transfer the

active energy accumulated in the 32-bit internal accumulation

registers into the xWAT THR or xFWAT THR registers after an

integral number of line cycles, as shown in Figure 70. The

number of half line cycles is specified in the LINECYC register.

The maximum value that can be stored in the watt-hour

accumulation register before it overflows is 2³¹− 1 or

0x7FFFFFFF. The integration time is calculated as

Time = 0x7FFF,FFFF × 125 μs = 74 hr 33 min 55 sec (27)

Energy Accumulation Modes

The active power accumulated in each watt-hour accumulation

32-bit register (AWATTHR, BWATTHR, CWATTHR,

AFWAT THR, BFWATTHR, and CFWATTHR) depends on the

configuration of Bit 5 and Bit 4 (CONSEL bits) in the ACCMODE

register. The various configurations are described in Table 15.

Rev. H | Page 51 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

ZXSEL[0] IN

LCYCMODE[7:0]

Because the active power is integrated on an integer number of

half-line cycles in this mode, the sinusoidal components are

reduced to 0, eliminating any ripple in the energy calculation.

Therefore, total energy accumulated using the line cycle

accumulation mode is

ZERO-

CROSSING

DETECTION

(PHASE A)

ZXSEL[1] IN

LCYCMODE[7:0]

LINECYC[15:0]

t+nT

∞

ZERO-

e =

p

(

t

)

dt = nT V I cos(φ_k– γ_k)

(28)

∑

∫

k

CROSSING

DETECTION

(PHASE B)

CALIBRATION

CONTROL

k=1

t

where nT is the accumulation time.

ZXSEL[2] IN

LCYCMODE[7:0]

Note that line cycle active energy accumulation uses the same

signal path as the active energy accumulation. The LSB size of

these two methods is equivalent.

ZERO-

CROSSING

DETECTION

(PHASE C)

REACTIVE POWER CALCULATION—ADE7858,

ADE7868, ADE7878 ONLY

AWATTOS

The ADE7858/ADE7868/ADE7878 can compute the total

reactive power on every phase. Total reactive power integrates

all fundamental and harmonic components of the voltages and

currents. The ADE7878 also computes the fundamental reactive

power, the power determined only by the fundamental

components of the voltages and currents.

AWGAIN

AWATTHR[31:0]

OUTPUT

FROM LPF2

ACCUMULATOR

WTHR[47:0]

32-BIT

REGISTER

Figure 70. Line Cycle Active Energy Accumulation Mode

A load that contains a reactive element (inductor or capacitor)

produces a phase difference between the applied ac voltage and

the resulting current. The power associated with reactive elements

is called reactive power, and its unit is VAR. Reactive power is

defined as the product of the voltage and current waveforms when

all harmonic components of one of these signals are phase

shifted by 90°.

The line cycle energy accumulation mode is activated by setting

Bit 0 (LWATT) in the LCYCMODE register. The energy accu-

mulation over an integer number of half line cycles is written

to the watt-hour accumulation registers after LINECYC number

of half line cycles is detected. When using the line cycle

accumulation mode, the Bit 6 (RSTREAD) of the LCYCMODE

register should be set to Logic 0 because the read with reset of

watt-hour registers is not available in this mode.

Equation 31 gives an expression for the instantaneous reactive

power signal in an ac system when the phase of the current

channel is shifted by +90°.

Phase A, Phase B, and Phase C zero crossings are, respectively,

included when counting the number of half line cycles by setting

Bits[5:3] (ZXSEL[x]) in the LCYCMODE register. Any combi-

nation of the zero crossings from all three phases can be used

for counting the zero crossing. Select only one phase at a time

for inclusion in the zero crossings count during calibration.

∞

v(t) =

V

2 sin(kωt + φ_k)

2 sin kωt + γ_k

(29)

(30)

∑

k

k=1

∞

i(t) =

I

(

)

∑

k

k=1

The number of zero crossings is specified by the LINECYC 16-bit

unsigned register. The ADE78xx can accumulate active power

for up to 65,535 combined zero crossings. Note that the internal

zero-crossing counter is always active. By setting Bit 0 (LWATT)

in the LCYCMODE register, the first energy accumulation

result is, therefore, incorrect. Writing to the LINECYC register

when the LWATT bit is set resets the zero-crossing counter, thus

ensuring that the first energy accumulation result is accurate.

∞

π

2











i'(t) =

I

2 sin kωt + γ +

∑



k

k=1

where iʹ(t) is the current waveform with all harmonic

components phase shifted by 90°.

Next, the instantaneous reactive power, q(t), can be expressed as

q(t) = v(t) × iʹ(t)

(31)

∞

At the end of an energy calibration cycle, Bit 5 (LENERGY) in

the STATUS0 register is set. If the corresponding mask bit in

π

2

q(t) = V I ×2 sin(kωt + φ_k) × sin(kωt + γ_k+ ) +

∑

k

k=1

∞

IRQ0

the MASK0 interrupt mask register is enabled, the

IRQ0

π

2

V I × 2sin(kωt + φ_k) × sin(mωt + γ_m+

)

∑

k,m=1

k≠m

m

k

also goes active low. The status bit is cleared and the

pin is

set to high again by writing to the STATUS0 register with the

corresponding bit set to 1.

Rev. H | Page 52 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Note that q(t) can be rewritten as

Table 17 presents the settling time for the fundamental reactive

power measurement, which is the time it takes the power to

reflect the value at the input of the ADE7878.

∞

π

2

q(t) = ^{V I}{cos(φ_k− γ_k− ) − cos(2 kωt + φ_k+ γ_k+ )}+

∑

k

2

k=1

Table 17. Settling Time for Fundamental Reactive Power

∞

π

2

V I

{

cos[(k – m)ωt + φ_k− γ_k− ]−

∑

m

k

Input Signals

k,m=1

k≠m

63% Full Scale

100% Full Scale

375 ms

875 ms

π

2

^cos[(k + m)ωt + φ_k+ γ_k+ ]}

(32)

Reactive Power Gain Calibration

The average reactive power in each phase can be scaled by

100% by writing to one of the phase’s VAR gain 24-bit registers

(AVARGAIN, BVARGAIN, CVARGAIN, AFVARGAIN,

BFVARGAIN, or CFVARGAIN). The xVARGAIN registers are

placed in each phase of the total reactive power datapath. The

xFVARGAIN registers are placed in each phase of the fundamental

reactive power datapath. The xVARGAIN registers are twos com-

plement signed registers and have a resolution of 2⁻²³/LSB. The

function of the xVARGAIN registers is expressed by

The average total reactive power over an integral number of line

cycles (n) is given by the expression in Equation 33.

nT

dt = ^∞V I cos(φ_k– γ_k−

)

(33)

1

nT

π

2

Q =

q

(

t

)

∑

∫

k

k=1

0

∞

Q = V I sin(φ_k– γ_k)

∑

k

k=1

where:

T is the period of the line cycle.

Q is referred to as the total reactive power. Note that the total

reactive power is equal to the dc component of the instantaneous

reactive power signal q(t) in Equation 32, that is,

Average Reactive Power =

(35)

xVARGAIN Register







LPF2Output × 1 +



2²³





∞

The output is scaled by –50% by writing 0xC00000 to the

xVARGAIN registers and increased by +50% by writing

V I sin(φ_k– γ_k)

∑

k

k=1

0x400000 to them. These registers can be used to calibrate the

reactive power (or energy) gain in the ADE78xx for each phase.

This is the relationship used to calculate the total reactive power

in the ADE7858/ADE7868/ADE7878 for each phase. The

instantaneous reactive power signal, q(t), is generated by multi-

plying each harmonic of the voltage signals by the 90° phase-

shifted corresponding harmonic of the current in each phase.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE7858/ADE7868/ADE7878 work on 32-,

16-, or 8-bit words and the DSP works on 28 bits. Similar to

registers presented in Figure 35, the AVARGAIN, BVARGAIN,

CVARGAIN, AFVARGAIN, BFVARGAIN, and CFVARGAIN

24-bit signed registers are accessed as 32-bit registers with the

four MSBs padded with 0s and sign extended to 28 bits.

The ADE7858/ADE7868/ADE7878 store the instantaneous

total phase reactive powers into the AVAR, BVAR, and CVAR

registers. Their expression is

∞

V_k

I_k

1

xVAR =

×

× sin(φ_k– γ_k) × PMAX ×

(34)

∑

Reactive Power Offset Calibration

_k=1V_FSI_FS

2⁴

The ADE7858/ADE7868/ADE7878 provide a reactive power

offset register on each phase and on each reactive power. AVAROS,

BVAROS, and CVAROS registers compensate the offsets in the

total reactive power calculations, whereas AFVAROS, BFVAROS,

and CFVAROS registers compensate offsets in the fundamental

reactive power calculations. These are signed twos complement,

24-bit registers that are used to remove offsets in the reactive

power calculations. An offset can exist in the power calculation

due to crosstalk between channels on the PCB or in the chip

itself. The offset resolution of the registers is the same as for the

active power offset registers (see the Active Power Offset

Calibration section).

where:

V_FS, I_FSare the rms values of the phase voltage and current when

the ADC inputs are at full scale.

PMAX = 33,516,139, the instantaneous power computed when

the ADC inputs are at full scale and in phase.

The xVAR waveform registers can be accessed using various

serial ports. Refer to the Waveform Sampling Mode section for

more details.

The expression of fundamental reactive power is obtained from

Equation 33 with k = 1, as follows:

FQ = V₁I₁sin(φ₁– γ₁)

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE7858/ADE7868/ADE7878 work on 32-,

16-, or 8-bit words and the DSP works on 28 bits. Similar to the

registers presented in Figure 35, the AVAROS, BVAROS, and

CVAROS 24-bit signed registers are accessed as 32-bit registers

with the four MSBs padded with 0s and sign extended to 28 bits.

The ADE7878 computes the fundamental reactive power using

a proprietary algorithm that requires some initialization function

of the frequency of the network and its nominal voltage measured

in the voltage channel. These initializations are introduced in

the Active Power Calculation section and are common for both

fundamental active and reactive powers.

Rev. H | Page 53 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Sign of Reactive Power Calculation

Both total and fundamental reactive energy accumulations are

always a signed operation. Negative energy is subtracted from

the reactive energy contents.

Note that the reactive power is a signed calculation. Table 18

summarizes the relationship between the phase difference between

the voltage and the current and the sign of the resulting reactive

power calculation.

Similar to active power, the ADE7858/ADE7868/ADE7878

achieve the integration of the reactive power signal in two

stages (see Figure 71). The process is identical for both total and

fundamental reactive powers.

The ADE7858/ADE7868/ADE7878 have sign detection circuitry

for reactive power calculations that can monitor the total reactive

powers or the fundamental reactive powers. As described in the

Reactive Energy Calculation section, the reactive energy accu-

mulation is executed in two stages. Every time a sign change is

detected in the energy accumulation at the end of the first stage,

that is, after the energy accumulated into the internal accumulator

reaches the VARTHR register threshold, a dedicated interrupt is

triggered. The sign of each phase reactive power can be read in

the PHSIGN register. Bit 7 (REVRPSEL) in the ACCMODE

register sets the type of reactive power being monitored. When

REVRPSEL is 0, the default value, the total reactive power is

monitored. When REVRPSEL is 1, then the fundamental

reactive power is monitored.

•

The first stage is conducted inside the DSP: every 125 µs

(8 kHz frequency), the instantaneous phase total reactive

or fundamental power is accumulated into an internal

register. When a threshold is reached, a pulse is generated

at the processor port and the threshold is subtracted from

the internal register. The sign of the energy in this moment

is considered the sign of the reactive power (see the Sign of

Reactive Power Calculation section for details).

•

The second stage is performed outside the DSP and consists

in accumulating the pulses generated by the processor into

internal 32-bit accumulation registers. The content of these

registers is transferred to the var-hour registers (xVARHR and

xFVARHR) when these registers are accessed. AVARHR,

BVARHR, CVARHR, AFWATTHR, BFWATTHR, and

CFWATTHR represent phase fundamental reactive powers.

Bits[12:10] (REVRPC, REVRPB, and REVRPA, respectively)

in the STATUS0 register are set when a sign change occurs in

the power selected by Bit 7 (REVRPSEL) in the ACCMODE

register.

Figure 68 from the Active Energy Calculation section explains

this process. The VARTHR 48-bit signed register contains the

threshold and it is introduced by the user. It is common for both

total and fundamental phase reactive powers. Its value depends

on how much energy is assigned to one LSB of var-hour

registers. When a derivative of reactive energy (varh) of [10ⁿ

varh], where n is an integer, is desired as one LSB of the

xVARHR register; then, the xVARTHR register can be computed

using the following equation:

Bits[6:4] (CVARSIGN, BVARSIGN, and AVARSIGN, respectively)

in the PHSIGN register are set simultaneously with the REVRPC,

REVRPB, and REVRPA bits. They indicate the sign of the reactive

power. When they are 0, the reactive power is positive. When

they are 1, the reactive power is negative.

Bit REVRPx of the STATUS0 register and Bit xVARSIGN in the

PHSIGN register refer to the reactive power of Phase x, the

power type being selected by Bit REVRPSEL in ACCMODE

register.

PMAX × f_s×3600 ×10ⁿ

VARTHR =

Setting Bits[12:10] in the MASK0 register enables the REVRPC,

REVRPB, and REVRPA interrupts, respectively. If enabled, the

V_FS× I_FS

where:

IRQ0

pin is set low and the status bit is set to 1 whenever a change

PMAX = 33,516,139 = 0x1FF6A6B, the instantaneous power

computed when the ADC inputs are at full scale.

f_S= 8 kHz, the frequency with which the DSP computes the

instantaneous power.

V_FS, I_FSare the rms values of phase voltages and currents when

the ADC inputs are at full scale.

of sign occurs. To find the phase that triggered the interrupt,

the PHSIGN register is read immediately after reading the

STATUS0 register. Next, the status bit is cleared and the

pin is set to high by writing to the STATUS0 register with the

corresponding bit set to 1.

IRQ0

Table 18. Sign of Reactive Power Calculation

The maximum value that may be written on the VARTHR

register is 2⁴⁷− 1. The minimum value is 0x0, but it is

recommended to write a number equal to or greater than

PMAX. Never use negative numbers.

Φ¹

Integrator

Sign of Reactive Power

Between 0 to +180

Between −180 to 0

Between 0 to +180

Between −180 to 0

Off

On

Positive

Negative

Positive

Negative

VARTHR is a 48-bit register. As previously stated in the Voltage

Waveform Gain Registers section, the serial ports of the ADE7858/

ADE7868/ADE7878 work on 32-, 16-, or 8-bit words. Similar to

the WTHR register shown in Figure 69, VARTHR is accessed as

two 32-bit registers (VARTHR1 and VARTHR0), each having eight

MSBs padded with 0s.

¹Φ is defined as the phase angle of the voltage signal minus the current

signal; that is, Φ is positive if the load is inductive and negative if the load is

capacitive.

Reactive Energy Calculation

Reactive energy is defined as the integral of reactive power.

Reactive Energy = ∫q(t)dt

(36)

Rev. H | Page 54 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

This discrete time accumulation or summation is equivalent to

integration in continuous time following the expression in

Equation 37:

Bit 2 (REHF) in the STATUS0 register is set when Bit 30 of

one of the xVARHR registers changes, signifying one of these

registers is half full. If the reactive power is positive, the var-hour

register becomes half full when it increments from 0x3FFF FFFF

to 0x4000 0000. If the reactive power is negative, the var-hour

register becomes half full when it decrements from 0xC000 0000

to 0xBFFF FFFF. Analogously, Bit 3 (FREHF) in the STATUS0

register is set when Bit 30 of one of the xFVARHR registers

changes, signifying one of these registers is half full.

 ^∞







ReactiveEnergy = q

(

t

)

dt =

q

(

nT

)

× T

(37)

Lim

∑

_T→0

∫

n=0



where:

n is the discrete time sample number.

T is the sample period.

Setting Bits[3:2] in the MASK0 register enable the FREHF and

On the ADE7858/ADE7868/ADE7878, the total phase reactive

powers are accumulated in the AVARHR, BVARHR, and

CVARHR 32-bit signed registers. The fundamental phase reactive

powers are accumulated in the AFVARHR, BFVARHR, and

CFVARHR 32-bit signed registers. The reactive energy register

content can roll over to full-scale negative (0x80000000) and

continue increasing in value when the reactive power is positive.

Conversely, if the reactive power is negative, the energy register

underflows to full-scale positive (0x7FFFFFFF) and continues

to decrease in value.

IRQ0

REHF interrupts, respectively. If enabled, the

pin is set

low and the status bit is set to 1 whenever one of the energy

registers, xVARHR (for REHF interrupt) or xFVARHR (for

FREHF interrupt), becomes half full. The status bit is cleared

IRQ0

and the

pin is set to high by writing to the STATUS0

register with the corresponding bit set to 1.

Setting Bit 6 (RSTREAD) of the LCYCMODE register enables a

read-with-reset for all var-hour accumulation registers, that is,

the registers are reset to 0 after a read operation.

HPFDIS

[23:0]

DIGITAL

INTEGRATOR

AIGAIN

AVARGAIN

AVAROS

REVRPA BIT IN

STATUS0[31:0]

IA

HPF

AVARHR[31:0]

HPFDIS

[23:0]

TOTAL

REACTIVE

POWER

APHCAL

AVGAIN

ACCUMULATOR

ALGORITHM

32-BIT

REGISTER

VA

VARTHR[47:0]

AVAR

HPF

4

2

DIGITAL SIGNAL PROCESSOR

Figure 71. Total Reactive Energy Accumulation

Rev. H | Page 55 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Integration Time Under A Steady Load

In this mode, the ADE7858/ADE7868/ADE7878 transfer the

reactive energy accumulated in the 32-bit internal accumulation

registers into the xVARHR or xFVARHR registers after an

integral number of line cycles, as shown in Figure 72. The

number of half line cycles is specified in the LINECYC register.

The discrete time sample period (T) for the accumulation register

is 125 µs (8 kHz frequency). With full-scale pure sinusoidal signals

on the analog inputs and a 90° phase difference between the vol-

tage and the current signal (the largest possible reactive power),

the average word value representing the reactive power is PMAX =

33,516,139 = 0x1FF6A6B. If the VARTHR threshold is set at the

PMAX level, this means the DSP generates a pulse that is added

at the var-hour registers every 125 µs.

The line cycle reactive energy accumulation mode is activated by

setting Bit 1 (LVAR) in the LCYCMODE register. The total reactive

energy accumulated over an integer number of half line cycles

or zero crossings is available in the var-hour accumulation registers

after the number of zero crossings specified in the LINECYC reg-

ister is detected. When using the line cycle accumulation mode,

Bit 6 (RSTREAD) of the LCYCMODE register should be set to

Logic 0 because a read with the reset of var-hour registers is not

available in this mode.

The maximum value that can be stored in the var-hour

accumulation register before it overflows is 2³¹− 1 or

0x7FFFFFFF. The integration time is calculated as

Time = 0x7FFF,FFFF × 125 μs = 74 hr 33 min 55 sec (38)

ZXSEL[0] IN

LCYCMODE[7:0]

Energy Accumulation Modes

The reactive power accumulated in each var-hour accumulation

32-bit register (AVARHR, BVARHR, CVARHR, AFVARHR,

BFVARHR, and CFVARHR) depends on the configuration of

Bits[5:4] (CONSEL[1:0]) in the ACCMODE register, in correlation

with the watt-hour registers. The different configurations are

described in Table 19. Note that IA’/IB’/IC’ are the phase-shifted

current waveforms.

ZERO-

CROSSING

DETECTION

(PHASE A)

ZXSEL[1] IN

LCYCMODE[7:0]

LINECYC[15:0]

ZERO-

CROSSING

DETECTION

(PHASE B)

CALIBRATION

CONTROL

Table 19. Inputs to Var-Hour Accumulation Registers

ZXSEL[2] IN

LCYCMODE[7:0]

AVARHR,

CONSEL[1:0] AFVARHR

BVARHR,

BFVARHR

CVARHR,

CFVARHR

ZERO-

CROSSING

DETECTION

(PHASE C)

00

01

10

VA × IA’

VB × IB’

0

VB × IB’

VB = −VA − VC

VB × IB’

VB = −VA

VC × IC’

AVAROS

AVARGAIN

AVARHR[31:0]

11

VA × IA’

VC × IC’

OUTPUT

FROM

TOTAL

ACCUMULATOR

VARTHR[47:0]

32-BIT

REGISTER

REACTIVE

POWER

ALGORITHM

Bits[3:2] (VARACC[1:0]) in the ACCMODE register determine

how CF frequency output can be a generated function of the total

and fundamental reactive powers. While the var-hour accumu-

lation registers accumulate the reactive power in a signed

format, the frequency output can be generated in either the signed

mode or the sign adjusted mode function of VARACC[1:0]. See

the Energy-to-Frequency Conversion section for details.

Figure 72. Line Cycle Total Reactive Energy Accumulation Mode

Phase A, Phase B, and Phase C zero crossings are, respectively,

included when counting the number of half line cycles by setting

Bits[5:3] (ZXSEL[x]) in the LCYCMODE register. Any combi-

nation of the zero crossings from all three phases can be used

for counting the zero crossing. Select only one phase at a time

for inclusion in the zero-crossings count during calibration.

Line Cycle Reactive Energy Accumulation Mode

As mentioned in the Line Cycle Active Energy Accumulation

Mode section, in line cycle energy accumulation mode, the

energy accumulation can be synchronized to the voltage

channel zero crossings so that reactive energy can be accu-

mulated over an integral number of half line cycles.

For details on setting the LINECYC register and the Bit 5

(LENERGY) in the MASK0 interrupt mask register associated

with the line cycle accumulation mode, see the Line Cycle

Active Energy Accumulation Mode section.

Rev. H | Page 56 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

The ADE7854/ADE7858/ADE7868/ADE7878 store the instan-

taneous phase apparent powers into the AVA, BVA, and CVA

registers. Their expression is

APPARENT POWER CALCULATION

Apparent power is defined as the maximum power that can be

delivered to a load. One way to obtain the apparent power is by

multiplying the voltage rms value by the current rms value (also

called the arithmetic apparent power)

V

I

1

xVA =

×

× PMAX ×

(40)

V_FSI_FS

2⁴

S = V rms × I rms

where:

S is the apparent power.

(39)

where:

V, I are the rms values of the phase voltage and current.

V_FS, I_FSare the rms values of the phase voltage and current when

the ADC inputs are at full scale.

V rms and I rms are the rms voltage and current, respectively.

PMAX = 33,516,139, the instantaneous power computed when

the ADC inputs are at full scale and in phase.

The ADE7854/ADE7858/ADE7868/ADE7878 compute the

arithmetic apparent power on each phase. Figure 73 illustrates

the signal processing in each phase for the calculation of the

apparent power in the ADE78xx. Because V rms and I rms con-

tain all harmonic information, the apparent power computed by

the ADE78xx is total apparent power. The ADE7878 does not

compute fundamental apparent power because it does not measure

the rms values of the fundamental voltages and currents.

The xVA[23:0] waveform registers may be accessed using

various serial ports. Refer to the Waveform Sampling Mode

section for more details.

The ADE7854/ADE7858/ADE7868/ADE7878 can compute the

apparent power in an alternative way by multiplying the phase

rms current by an rms voltage introduced externally. See the

Apparent Power Calculation Using VNOM section for details.

AIRMS

AVRMS

AVAGAIN

AVAHR[31:0]

ACCUMULATOR

AVA VATHR[47:0]

32-BIT REGISTER

4

2

DIGITAL SIGNAL PROCESSOR

Figure 73. Apparent Power Data Flow and Apparent Energy Accumulation

Rev. H | Page 57 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Apparent Power Gain Calibration

As stated in the Current Waveform Gain Registers, the serial

ports of the ADE78xx work on 32-, 16-, or 8-bit words. Similar

to the register presented in Figure 36, the VNOM 24-bit signed

register is accessed as a 32-bit register with the eight MSBs

padded with 0s.

The average apparent power result in each phase can be scaled

by 100% by writing to one of the phase’s VAGAIN 24-bit registers

(AVAGAIN, BVAGAIN, or CVAG AIN). The VAGAIN registers

are twos complement, signed registers and have a resolution of

2⁻²³/LSB. The function of the xVAGAIN registers is expressed

mathematically as

Apparent Energy Calculation

Apparent energy is defined as the integral of apparent power.

Average Apparent Power =

Apparent Energy = ∫s(t)dt

(43)

(41)

VAGAIN Register







Similar to active and reactive powers, the ADE7854/ADE7858/

ADE7868/ADE7878 achieve the integration of the apparent power

signal in two stages (see Figure 73). The first stage is conducted

inside the DSP: every 125 µs (8 kHz frequency), the instanta-

neous phase apparent power is accumulated into an internal

register. When a threshold is reached, a pulse is generated at the

processor port and the threshold is subtracted from the internal

register. The second stage is conducted outside the DSP and

consists of accumulating the pulses generated by the processor

into internal 32-bit accumulation registers. The content of these

registers is transferred to the VA-hour registers, xVAHR, when

these registers are accessed. Figure 68 from the Active Energy

Calculation section illustrates this process. The VATHR 48-bit

register contains the threshold. Its value depends on how much

energy is assigned to one LSB of the VA-hour registers. When a

derivative of apparent energy (VAh) of [10ⁿVAh], where n is an

integer, is desired as one LSB of the xVAHR register; then, the

xVATHR register can be computed using the following equation:

V rms×I rms × 1 +



2²³





The output is scaled by –50% by writing 0xC00000 to the

xVAGAIN registers, and it is increased by +50% by writing

0x400000 to them. These registers calibrate the apparent power

(or energy) calculation in the ADE7854/ADE7858/ADE7868/

ADE7878 for each phase.

As previously stated in the Current Waveform Gain Registers

section, the serial ports of the ADE78xx work on 32-, 16-, or 8-bit

words and the DSP works on 28 bits. Similar to registers presented

in Figure 35, the AVAGAIN, BVAGAIN, and CVAGAIN 24-bit

registers are accessed as 32-bit registers with the four MSBs

padded with 0s and sign extended to 28 bits.

Apparent Power Offset Calibration

Each rms measurement includes an offset compensation register

to calibrate and eliminate the dc component in the rms value

(see the Root Mean Square Measurement section). The voltage

and current rms values are multiplied together in the apparent

power signal processing. As no additional offsets are created in

the multiplication of the rms values, there is no specific offset

compensation in the apparent power signal processing. The offset

compensation of the apparent power measurement in each phase is

accomplished by calibrating each individual rms measurement.

PMAX × f_s× 3600 ×10ⁿ

VATHR =

V_FS× I_FS

where:

PMAX = 33,516,139 = 0x1FF6A6B, the instantaneous power

computed when the ADC inputs are at full scale.

f_S= 8 kHz, the frequency with which the DSP computes the

instantaneous power.

V_FS, I_FSare the rms values of phase voltages and currents when

the ADC inputs are at full scale.

Apparent Power Calculation Using VNOM

The ADE7854/ADE7858/ADE7868/ADE7878 can compute the

apparent power by multiplying the phase rms current by an rms

voltage introduced externally in the VNOM 24-bit signed register.

VATHR is a 48-bit register. As previously stated in the Current

Waveform Gain Registers section, the serial ports of the ADE7854/

ADE7858/ADE7868/ADE7878 work on 32-, 16-, or 8-bit words.

Similar to the WTHR register presented in Figure 69, the VATHR

register is accessed as two 32-bit registers (VATHR1 and VATHR0),

each having eight MSBs padded with 0s.

When one of Bits[13:11] (VNOMCEN, VNOMBEN, or

VNOMAEN) in the COMPMODE register is set to 1, the

apparent power in the corresponding phase (Phase x for

VNOMxEN) is computed in this way. When the VNOMxEN

bits are cleared to 0, the default value, then the arithmetic

apparent power is computed.

This discrete time accumulation or summation is equivalent to

integration in continuous time following the description in

Equation 44.

The VNOM register contains a number determined by V, the

desired rms voltage, and V_FS, the rms value of the phase voltage

when the ADC inputs are at full scale:

 ^∞







V

ApparentEnergy = s

(

t

)

dt =

s

(

nT

)

× T

(44)

Lim

∑

_T→0

∫

VNOM =

× 4,191,910

(42)

n=0



V_FS

where V is the desired nominal phase rms voltage.

where:

n is the discrete time sample number.

T is the sample period.

Rev. H | Page 58 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

In the ADE7854/ADE7858/ADE7868/ADE7878, the phase

apparent powers are accumulated in the AVAHR, BVAHR, and

CVAHR 32-bit signed registers. The apparent energy register

content can roll over to full-scale negative (0x80000000) and

continue increasing in value when the apparent power is

positive.

The maximum value that can be stored in the xVAHR

accumulation register before it overflows is 2³¹− 1 or

0x7FFFFFFF. The integration time is calculated as

Time = 0x7FFF,FFFF × 125 ꢀs = 74 hr 33 min 55 sec (45)

Energy Accumulation Mode

The apparent power accumulated in each accumulation register

depends on the configuration of Bits[5:4] (CONSEL[1:0]) in the

ACCMODE register. The various configurations are described

in Table 20.

Bit 4 (VAEHF) in the STATUS0 register is set when Bit 30 of one of

the xVAHR registers changes, signifying one of these registers is

half full. As the apparent power is always positive and the xVAHR

registers are signed, the VA-hour registers become half full when

they increment from 0x3FFFFFFF to 0x4000 0000. Interrupts

attached to Bit VAEHF in the STATUS0 register can be enabled by

Table 20. Inputs to VA-Hour Accumulation Registers

CONSEL[1:0]

AVAHR

BVAHR

CVAHR

IRQ0

setting Bit 4 in the MASK0 register. If enabled, the

pin is set

00

01

10

AVRMS × AIRMS

BVRMS × BIRMS

0

CVRMS × CIRMS

low and the status bit is set to 1 whenever one of the Energy

Registers xVAHR becomes half full. The status bit is cleared and

BVRMS × BIRMS

VB = −VA − VC

BVRMS × BIRMS

VB = −VA

IRQ0

the

pin is set to high by writing to the STATUS0 register

11

AVRMS × AIRMS

CVRMS × CIRMS

with the corresponding bit set to 1.

Setting Bit 6 (RSTREAD) of the LCYCMODE register enables

a read-with-reset for all xVAHR accumulation registers, that is,

the registers are reset to 0 after a read operation.

Line Cycle Apparent Energy Accumulation Mode

As described in the Line Cycle Active Energy Accumulation

Mode section, in line cycle energy accumulation mode, the

energy accumulation can be synchronized to the voltage channel

zero crossings allowing apparent energy to be accumulated over an

integral number of half line cycles. In this mode, the ADE7854/

ADE7858/ADE7868/ADE7878transfer the apparent energy

accumulated in the 32-bit internal accumulation registers into

the xVAHR registers after an integral number of line cycles, as

shown in Figure 74. The number of half line cycles is specified

in the LINECYC register.

Integration Time Under Steady Load

The discrete time sample period for the accumulation register is

125 μs (8 kHz frequency). With full-scale pure sinusoidal signals

on the analog inputs, the average word value representing the

apparent power is PMAX. If the VATHR threshold register is set

at the PMAX level, this means the DSP generates a pulse that

is added at the xVAHR registers every 125 μs.

ZXSEL[0] IN

LCYCMODE[7:0]

ZERO-

CROSSING

DETECTION

(PHASE A)

ZXSEL[1] IN

LCYCMODE[7:0]

LINECYC[15:0]

ZERO-

CROSSING

DETECTION

(PHASE B)

CALIBRATION

CONTROL

ZXSEL[2] IN

LCYCMODE[7:0]

ZERO-

CROSSING

DETECTION

(PHASE C)

AIRMS

AVRMS

AVAGAIN

AVAHR[31:0]

ACCUMULATOR

VAHR[47:0]

32-BIT

REGISTER

Figure 74. Line Cycle Apparent Energy Accumulation Mode

Rev. H | Page 59 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

The line cycle apparent energy accumulation mode is activated

by setting Bit 2 (LVA) in the LCYCMODE register. The apparent

energy accumulated over an integer number of zero crossings is

written to the xVAHR accumulation registers after the number

of zero crossings specified in LINECYC register is detected. When

using the line cycle accumulation mode, set Bit 6 (RSTREAD) of

the LCYCMODE register to Logic 0 because a read with the reset

of xVAHR registers is not available in this mode.

The ADE7854/ADE7858/ADE7868/ADE7878 contain a high

speed data capture (HSDC) port that is specially designed to

provide fast access to the waveform sample registers. Read the

HSDC Interface section for more details.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE7854/ADE7858/ADE7868/ADE7878

work on 32-, 16-, or 8-bit words. All registers listed in Table 21

are transmitted signed extended from 24 bits to 32 bits (see

Figure 37).

Phase A, Phase B, and Phase C zero crossings are, respectively,

included when counting the number of half line cycles by setting

Bits[5:3] (ZXSEL[x]) in the LCYCMODE register. Any combi-

nation of the zero crossings from all three phases can be used

for counting the zero crossing. Select only one phase at a time

for inclusion in the zero-crossings count during calibration.

ENERGY-TO-FREQUENCY CONVERSION

The ADE7854/ADE7858/ADE7868/ADE7878 provide three

frequency output pins: CF1, CF2, and CF3. The CF3 pin is

multiplexed with the HSCLK pin of the HSDC interface. When

HSDC is enabled, the CF3 functionality is disabled at the pin.

CF1 and CF2 pins are always available. After initial calibration

at manufacturing, the manufacturer or end customer verifies

the energy meter calibration. One convenient way to verify the

meter calibration is to provide an output frequency propor-

tional to the active, reactive, or apparent powers under steady

load conditions. This output frequency can provide a simple,

single-wire, optically isolated interface to external calibration

equipment. Figure 75 illustrates the energy-to-frequency

conversion in the ADE7854/ADE7858/ADE7868/ADE7878.

For details on setting the LINECYC register and Bit 5 (LENERGY)

in the MASK0 interrupt mask register associated with the line

cycle accumulation mode, see the Line Cycle Active Energy

Accumulation Mode section.

WAVEFORM SAMPLING MODE

The waveform samples of the current and voltage waveform,

the active, reactive, and apparent power outputs are stored

every 125 µs (8 kHz rate) into 24-bit signed registers that can be

accessed through various serial ports of the ADE7854/ADE7858/

ADE7868/ADE7878. Table 21 provides a list of registers and their

descriptions.

The DSP computes the instantaneous values of all phase powers:

total active, fundamental active, total reactive, fundamental

reactive, and apparent. The process in which the energy is sign

accumulated in various xWATTHR, xVARHR, and xVAHR

registers has already been described in the energy calculation

sections: Active Energy Calculation, Reactive Energy Calculation,

and Apparent Energy Calculation. In the energy-to-frequency

conversion process, the instantaneous powers generate signals

at the frequency output pins (CF1, CF2, and CF3). One digital-

to-frequency converter is used for every CFx pin. Every converter

sums certain phase powers and generates a signal proportional

to the sum. Two sets of bits decide what powers are converted.

Table 21. Waveform Registers List

Register

Description

IAWV

VAWV

IBWV

VBWV

ICWV

VCWV

INWV

Phase A current

Phase A voltage

Phase B current

Phase B voltage

Phase C current

Phase C voltage

Neutral current, available in the ADE7868

and ADE7878 only

First, Bits[2:0] (TERMSEL1[2:0]), Bits[5:3] (TERMSEL2[2:0]),

and Bits[8:6] (TERMSEL3[2:0]) of the COMPMODE register

decide which phases, or which combination of phases, are added.

AVA

BVA

CVA

AWATT

BWATT

CWATT

AVAR

BVAR

CVAR

Phase A apparent power

Phase B apparent power

Phase C apparent power

Phase A active power

Phase B active power

Phase C active power

Phase A reactive power

Phase B reactive power

Phase C reactive power

The TERMSEL1 bits refer to the CF1 pin, the TERMSEL2 bits

refer to the CF2 pin, and the TERMSEL3 bits refer to the CF3

pin. The TERMSELx[0] bits manage Phase A. When set to 1,

Phase A power is included in the sum of powers at the CFx

converter. When cleared to 0, Phase A power is not included.

The TERMSELx[1] bits manage Phase B, and the TERMSELx[2]

bits manage Phase C. Setting all TERMSELx bits to 1 means all

3-phase powers are added at the CFx converter. Clearing all

TERMSELx bits to 0 means no phase power is added and no

CF pulse is generated.

Bit 17 (DREADY) in the STATUS0 register can be used to

signal when the registers listed in Table 21 can be read using

I²C or SPI serial ports. An interrupt attached to the flag can be

enabled by setting Bit 17 (DREADY) in the MASK0 register.

See the Digital Signal Processor section for more details on

Bit DREADY.

Rev. H | Page 60 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Second, Bits[2:0] (CF1SEL[2:0]), Bits[5:3] (CF2SEL[2:0]), and

Bits[8:6] (CF3SEL[2:0]) in the CFMODE register decide what

type of power is used at the inputs of the CF1, CF2, and CF3

converters, respectively. Table 22 shows the values that CFxSEL

can have: total active, total reactive (available in the ADE7858,

ADE7868, and ADE7878 only), apparent, fundamental active

(available in the ADE7878 only), or fundamental reactive

(available in the ADE7878 only) powers.

Table 22. CFxSEL Bits Description

Registers

Latched When

CFxLATCH = 1

CFxSEL

Description

000

CFx signal proportional to the

sum of total phase active

powers

AWATTHR,

BWATTHR,

CWATTHR

AVARHR, BVARHR,

CVARHR

001

CFx signal proportional to the

sum of total phase reactive

powers (ADE7858/ADE7868/

ADE7878)

010

011

CFx signal proportional to the

sum of phase apparent powers

CFx signal proportional to the

sum of fundamental phase

active powers (ADE7878 only)

AVAHR, BVAHR,

CVAHR

AFWATTHR,

BFWATTHR,

CFWATTHR

100

CFx signal proportional to the

sum of fundamental phase

AFVARHR,

BFVARHR,

reactive powers (ADE7878 only) CFVARHR

101 to

111

Reserved

CFxSEL BITS

IN CFMODE

INSTANTANEOUS

PHASE A ACTIVE

TERMSELx BITS IN

POWER

7

2

COMPMODE

VA

REVPSUMx BIT OF

STATUS0[31:0]

INSTANTANEOUS

PHASE B ACTIVE

POWER

WATT

VAR

ACCUMULATOR

FREQUENCY

DIVIDER

CFx PULSE

OUTPUT

1

FWATT

INSTANTANEOUS

PHASE C ACTIVE

POWER

WTHR[47:0]

1

FVAR

CFxDEN

DIGITAL SIGNAL

PROCESSOR

7

2

1

FWATT AND FVAR FOR ADE7878 ONLY.

Figure 75. Energy-to-Frequency Conversion

Rev. H | Page 61 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

By default, the TERMSELx bits are all 1 and the CF1SEL bits are

000, the CF2SEL bits are 001, and the CF3SEL bits are 010. This

means that by default, the CF1 digital-to-frequency converter

produces signals proportional to the sum of all 3-phase total

active powers, CF2 produces signals proportional to total

reactive powers, and CF3 produces signals proportional to

apparent powers.

The pulse output is active low and preferably connected to an

LED, as shown in Figure 76.

V

DD

CFx PIN

Similar to the energy accumulation process, the energy-to-

frequency conversion is accomplished in two stages. In the first

stage, the instantaneous phase powers obtained from the DSP at

the 8 kHz rate are shifted left by seven bits and then accumulate

into an internal register at a 1 MHz rate. When a threshold is

reached, a pulse is generated and the threshold is subtracted

from the internal register. The sign of the energy in this moment

is considered the sign of the sum of phase powers (see the Sign

of Sum-of-Phase Powers in the CFx Datapath section for details).

The threshold is the same threshold used in various active,

reactive, and apparent energy accumulators in the DSP, such

as the WTHR, VARTHR , or VATHR registers, except for being

shifted left by seven bits. The advantage of accumulating the

instantaneous powers at the 1 MHz rate is that the ripple at the

CFx pins is greatly diminished.

Figure 76. CFx Pin Recommended Connection

Bits[11:9] (CF3DIS, CF2DIS, and CF1DIS) of the CFMODE

register decide if the frequency converter output is generated

at the CF3, CF2, or CF1 pin. When Bit CFxDIS is set to 1 (the

default value), the CFx pin is disabled and the pin stays high.

When Bit CFxDIS is cleared to 0, the corresponding CFx pin

output generates an active low signal.

Bits[16:14] (CF3, CF2, CF1) in the Interrupt Mask Register MASK0

manage the CF3, CF2, and CF1 related interrupts. When the

CFx bits are set, whenever a high-to-low transition at the corres-

IRQ0

ponding frequency converter output occurs, an interrupt

is triggered and a status bit in the STATUS0 register is set to 1.

The interrupt is available even if the CFx output is not enabled

by the CFxDIS bits in the CFMODE register.

The second stage consists of the frequency divider by the

CFxDEN 16-bit unsigned registers. The values of CFxDEN

depend on the meter constant (MC), measured in impulses/kWh

and how much energy is assigned to one LSB of various energy

registers: xWATTHR, xVARHR, and so forth. Supposing a deri-

vative of wh [10ⁿwh], n a positive or negative integer, is desired

as one LSB of xWAT THR register. Then, CFxDEN is as follows:

Synchronizing Energy Registers with CFx Outputs

The ADE7854/ADE7858/ADE7868/ADE7878 contain a feature

that allows synchronizing the content of phase energy accu-

mulation registers with the generation of a CFx pulse. When

a high-to-low transition at one frequency converter output

occurs, the content of all internal phase energy registers that

relate to the power being output at CFx pin is latched into hour

registers and then resets to 0. See Table 22 for the list of registers

that are latched based on the CFxSEL[2:0] bits in the CFMODE

register. All 3-phase registers are latched independent of the

TERMSELx bits of the COMPMODE register. The process is

shown in Figure 77 for CF1SEL[2:0] = 010 (apparent powers

contribute at the CF1 pin) and CFCYC = 2.

10³

CFxDEN =

(46)

MC[imp/kwh]×10ⁿ

The derivative of wh must be chosen in such a way to obtain a

CFxDEN register content greater than 1. If CFxDEN = 1, then

the CFx pin stays active low for only 1 µs, therefore, avoid this

number. The frequency converter cannot accommodate fractional

results; the result of the division must be rounded to the nearest

integer. If CFxDEN is set equal to 0, then the ADE78xx considers it

to be equal to 1.

The CFCYC 8-bit unsigned register contains the number of high to

low transitions at the frequency converter output between two

consecutive latches. Avoid writing a new value into the CFCYC

register during a high-to-low transition at any CFx pin.

The pulse output for all digital-to-frequency converters stays

low for 80 ms if the pulse period is larger than 160 ms (6.25 Hz). If

the pulse period is smaller than 160 ms and CFxDEN is an even

number, the duty cycle of the pulse output is exactly 50%. If the

pulse period is smaller than 160 ms and CFxDEN is an odd

number, the duty cycle of the pulse output is

CF1 PULSE

BASED ON

PHASE A AND

PHASE B

APPARENT

POWERS

CFCYC = 2

AVAHR, BVAHR,

CVAHR LATCHED

ENERGY REGISTERS

RESET

AVAHR, BVAHR,

CVAHR LATCHED

ENERGY REGISTERS

RESET

(1+1/CFxDEN) × 50%

Figure 77. Synchronizing AVAHR and BVAHR with CF1

Bits[14:12] (CF3LATCH, CF2LATCH, and CF1LATCH) of the

CFMODE register enable this process when set to 1. When

cleared to 0, the default state, no latch occurs. The process is

available even if the CFx output is not enabled by the CFxDIS

bits in the CFMODE register.

Rev. H | Page 62 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

CF Outputs for Various Accumulation Modes

Bits[1:0] (WATTACC[1:0]) in the ACCMODE register deter-

mine the accumulation modes of the total active and fundamental

powers when signals proportional to the active powers are chosen

at the CFx pins (the CFxSEL[2:0] bits in the CFMODE register

equal 000 or 011). When WATTACC[1:0] = 00 (the default value),

the active powers are sign accumulated before entering the energy-

to-frequency converter. Figure 78 shows how signed active power

accumulation works. In this mode, the CFx pulses synchronize

perfectly with the active energy accumulated in xWAT THR regis-

ters because the powers are sign accumulated in both data paths.

ACTIVE ENERGY

NO-LOAD

THRESHOLD

ACTIVE POWER

NO-LOAD

THRESHOLD

REVAPx BIT

IN STATUS0

ACTIVE ENERGY

xWSIGN BIT

IN PHSIGN

POS

NEG POS NEG

APNOLOAD

SIGN = POSITIVE

NO-LOAD

THRESHOLD

Figure 79. Active Power Absolute Accumulation Mode

ACTIVE POWER

NO-LOAD

THRESHOLD

REACTIVE

ENERGY

REVAPx BIT

IN STATUS0

xWSIGN BIT

IN PHSIGN

NO-LOAD

THRESHOLD

POS

NEG POS NEG

APNOLOAD

SIGN = POSITIVE

REACTIVE

POWER

Figure 78. Active Power Signed Accumulation Mode

NO-LOAD

THRESHOLD

When WATTACC[1:0] = 11, the active powers are accumulated

in absolute mode. When the powers are negative, they change

sign and accumulate together with the positive power. Figure 79

shows how absolute active power accumulation works. Note

that in this mode, the xWAT THR registers continue to accumulate

active powers in signed mode, even if the CFx pulses are gener-

ated based on the absolute accumulation mode.

REVRPx BIT

IN STATUS0

xVARSIGN BIT

IN PHSIGN

POS

NEG POS NEG

VARNOLOAD

SIGN = POSITIVE

WATTACC[1:0] settings of 01 and 10 are reserved. The

ADE7854/ADE7858/ADE7868/ADE7878 behave identically to

the case when WATTACC[1:0] = 00.

Figure 80. Reactive Power Signed Accumulation Mode

When VARACC[1:0] = 10, the reactive powers are accumulated

depending on the sign of the corresponding active power. If the

active power is positive, the reactive power is accumulated as is.

If the active power is negative, the sign of the reactive power is

changed for accumulation. Figure 81 shows how the sign adjusted

reactive power accumulation mode works. In this mode, the

xVARHR registers continue to accumulate reactive powers in

signed mode, even if the CFx pulses are generated based on the

sign adjusted accumulation mode.

Bits[3:2] (VARACC[1:0]) in the ACCMODE register determine the

accumulation modes of the total and fundamental reactive powers

when signals proportional to the reactive powers are chosen at the

CFx pins (the CFxSEL[2:0] bits in the CFMODE register equal

001 or 100). When VARACC[1:0] = 00, the default value, the

reactive powers are sign accumulated before entering the

energy-to-frequency converter. Figure 80 shows how signed

reactive power accumulation works. In this mode, the CFx

pulses synchronize perfectly with the reactive energy accumu-

lated in the xVARHR registers because the powers are sign

accumulated in both datapaths.

VARACC[1:0] settings of 01 and 11 are reserved. The

ADE7854/ADE7858/ADE7868/ADE7878 behave identically to

the case when VARACC[1:0] = 00.

Rev. H | Page 63 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

NO LOAD CONDITION

The no load condition is defined in metering equipment standards

as occurring when the voltage is applied to the meter and no cur-

rent flows in the current circuit. To eliminate any creep effects in

the meter, the ADE7854/ADE7858/ADE7868/ADE7878contain

three separate no load detection circuits: one related to the total

active and reactive powers (ADE7858/ADE7868/ADE7878

only), one related to the fundamental active and reactive powers

(ADE7878 only), and one related to the apparent powers.

REACTIVE

ENERGY

NO-LOAD

THRESHOLD

REACTIVE

POWER

NO-LOAD

THRESHOLD

NO-LOAD

THRESHOLD

ACTIVE

POWER

No Load Detection Based On Total Active, Reactive

Powers

This no load condition is triggered when the absolute values of

both phase total active and reactive powers are less than or equal

to positive thresholds indicated in the respective APNOLOAD

and VARNOLOAD signed 24-bit registers. In this case, the total

active and reactive energies of that phase are not accumulated

and no CFx pulses are generated based on these energies. The

APNOLOAD register represents the positive no load level of

active power relative to PMAX, the maximum active power

obtained when full-scale voltages and currents are provided at

ADC inputs. The VARNOLOAD register represents the positive

no load level of reactive power relative to PMAX. The expres-

sion used to compute APNOLOAD signed 24-bit value is

REVRPx BIT

IN STATUS0

xVARSIGN BIT

IN PHSIGN

POS NEG POS

VARNOLOAD

SIGN = POSITIVE

Figure 81. Reactive Power Accumulation in Sign Adjusted Mode

Sign of Sum-of-Phase Powers in the CFx Datapath

The ADE7854/ADE7858/ADE7868/ADE7878 have sign

detection circuitry for the sum of phase powers that are used in

the CFx datapath. As seen in the beginning of the Energy-to-

Frequency Conversion section, the energy accumulation in the

CFx datapath is executed in two stages. Every time a sign change is

detected in the energy accumulation at the end of the first stage,

that is, after the energy accumulated into the accumulator

reaches one of the WTHR, VARTHR, or VATHR thresholds, a

dedicated interrupt can be triggered synchronously with the

corresponding CFx pulse. The sign of each sum can be read in

the PHSIGN register.

I_NOLOAD

I_FS

V_n

V_FS

APNOLOAD =

×

× PMAX

(47)

where:

PMAX = 33,516,139 = 0x1FF6A6B, the instantaneous power

computed when the ADC inputs are at full scale.

V_FS, I_FSare the rms values of phase voltages and currents when

Bit 18, Bit 13, and Bit 9 (REVPSUM3, REVPSUM2, and

REVPSUM1, respectively) of the STATUS0 register are set

to 1 when a sign change of the sum of powers in CF3, CF2,

or CF1 datapaths occurs. To correlate these events with the

pulses generated at the CFx pins, after a sign change occurs,

Bit REVPSUM3, Bit REVPSUM2, and Bit REVPSUM1 are set

in the same moment in which a high-to-low transition at the

CF3, CF2, and CF1 pin, respectively, occurs.

the ADC inputs are at full scale.

V_nis the nominal rms value of phase voltage.

I

_NOLOADis the minimum rms value of phase current the meter

starts measuring.

The VARNOLOAD register usually contains the same value as

the APNOLOAD register. When APNOLOAD and VARNOLOAD

are set to negative values, the no load detection circuit is disabled.

Note that the ADE7854 measures only the total active powers.

To ensure good functionality of the ADE7854 no-load circuit,

set the VARNOLOAD register at 0x800000.

Bit 8, Bit 7, and Bit 3 (SUM3SIGN, SUM2SIGN, and SUM1SIGN,

respectively) of the PHSIGN register are set in the same moment

with Bit REVPSUM3, Bit REVPSUM2, and Bit REVPSUM1 and

indicate the sign of the sum of phase powers. When cleared to

0, the sum is positive. When set to 1, the sum is negative.

As previously stated in the Current Waveform Gain Registers

section, the serial ports of the ADE78xx work on 32-, 16-, or

8-bit words and the DSP works on 28 bits. APNOLOAD and

VARNOLOAD 24-bit signed registers are accessed as 32-bit

registers with the four MSBs padded with 0s and sign extended

to 28 bits. See Figure 35 for details.

Interrupts attached to Bit 18, Bit 13, and Bit 9 (REVPSUM3,

REVPSUM2, and REVPSUM1, respectively) in the STATUS0

register are enabled by setting Bit 18, Bit 13, and Bit 9 in the

IRQ0

MASK0 register. If enabled, the

pin is set low, and the

Bit 0 (NLOAD) in the STATUS1 register is set when this no

load condition in one of the three phases is triggered. Bits[2:0]

(NLPHASE[2:0]) in the PHNOLOAD register indicate the state

of all phases relative to a no load condition and are set simulta-

neously with Bit NLOAD in the STATUS1 register. NLPHASE[0]

indicates the state of Phase A, NLPHASE[1] indicates the state

status bit is set to 1 whenever a change of sign occurs. To find

the phase that triggered the interrupt, the PHSIGN register is

read immediately after reading the STATUS0 register. Next, the

IRQ0

status bit is cleared, and the

pin is set high again by writing

to the STATUS0 register with the corresponding bit set to 1.

Rev. H | Page 64 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

of Phase B, and NLPHASE[2] indicates the state of Phase C.

When Bit NLPHASE[x] is cleared to 0, it means the phase is out

of a no load condition. When set to 1, it means the phase is in a

no load condition.

power obtained when full-scale voltages and currents are

provided at the ADC inputs. The expression used to compute

the VANOLOAD signed 24-bit value is

I_NOLOAD

I_FS

V_n

V_FS

VANOLOAD =

×

× PMAX

(48)

An interrupt attached to Bit 0 (NLOAD) in the STATUS1

register can be enabled by setting Bit 0 in the MASK1 register.

where:

IRQ1

If enabled, the

pin is set to low, and the status bit is set

PMAX = 33,516,139 = 0x1FF6A6B, the instantaneous apparent

power computed when the ADC inputs are at full scale.

V_FS, I_FSare the rms values of phase voltages and currents when

the ADC inputs are at full scale.

to 1 whenever one of three phases enters or exits this no load

condition. To find the phase that triggered the interrupt, the

PHNOLOAD register is read immediately after reading the

IRQ1

STATUS1 register. Next, the status bit is cleared, and the

V_nis the nominal rms value of phase voltage.

pin is set to high by writing to the STATUS1 register with the

corresponding bit set to 1.

I

_NOLOADis the minimum rms value of phase current the meter

starts measuring.

No Load Detection Based on Fundamental Active and

Reactive Powers—ADE7878 Only

When the VANOLOAD register is set to negative values, the no

load detection circuit is disabled.

This no load condition (available on the ADE7878 only) is

triggered when the absolute values of both phase fundamental

active and reactive powers are less than or equal to the respective

APNOLOAD and VARNOLOAD positive thresholds. In this

case, the fundamental active and reactive energies of that phase

are not accumulated, and no CFx pulses are generated based on

these energies. APNOLOAD and VARNOLOAD are the same

no load thresholds set for the total active and reactive powers.

When APNOLOAD and VARNOLOAD are set to negative

values, this no load detection circuit is disabled.

As stated in the Current Waveform Gain Registers section, the

serial ports of the ADE7854/ADE7858/ADE7868/ADE7878

work on 32-, 16-, or 8-bit words and the DSP works on 28 bits.

Similar to the registers presented in Figure 35, the VANOLOAD

24-bit signed register is accessed as a 32-bit register with the

four MSBs padded with 0s and sign extended to 28 bits.

Bit 2 (VANLOAD) in the STATUS1 register is set when this no

load condition in one of the three phases is triggered. Bits[8:6]

(VANLPHASE[2:0]) in the PHNOLOAD register indicate the

state of all phases relative to a no load condition and they are set

simultaneously with Bit VANLOAD in the STATUS1 register:

Bit 1 (FNLOAD) in the STATUS1 register is set when this no

load condition in one of the three phases is triggered. Bits[5:3]

(FNLPHASE[2:0]) in the PHNOLOAD register indicate the

state of all phases relative to a no load condition and are set

simultaneously with Bit FNLOAD in the STATUS1 register.

FNLPHASE[0] indicates the state of Phase A, FNLPHASE[1]

indicates the state of Phase B, and FNLPHASE[2] indicates the

state of Phase C. When Bit FNLPHASE[x] is cleared to 0, it

means the phase is out of the no load condition. When set to 1,

it means the phase is in a no load condition.

•

Bit VANLPHASE[0] indicates the state of Phase A.

Bit VANLPHASE[1] indicates the state of Phase B.

Bit VANLPHASE[2] indicates the state of Phase C.

When Bit VANLPHASE[x] is cleared to 0, it means the phase is

out of no load condition. When set to 1, it means the phase is in

no load condition.

An interrupt attached to Bit 2 (VANLOAD) in the STATUS1

register is enabled by setting Bit 2 in the MASK1 register. If

An interrupt attached to the Bit 1 (FNLOAD) in the STATUS1

register can be enabled by setting Bit 1 in the MASK1 register. If

IRQ1

enabled, the

pin is set low and the status bit is set to 1

whenever one of three phases enters or exits this no load

condition. To find the phase that triggered the interrupt, the

PHNOLOAD register is read immediately after reading the

IRQ1

enabled, the

pin is set low and the status bit is set to 1

whenever one of three phases enters or exits this no load

condition. To find the phase that triggered the interrupt, the

PHNOLOAD register is read immediately after reading the

IRQ1

STATUS1 register. Next, the status bit is cleared, and the

pin is set to high by writing to the STATUS1 register with the

corresponding bit set to 1.

IRQ1

STATUS1 register. Then the status bit is cleared and the

pin is set back high by writing to the STATUS1 register with the

corresponding bit set to 1.

CHECKSUM REGISTER

No Load Detection Based on Apparent Power

The ADE7854/ADE7858/ADE7868/ADE7878 have a checksum

32-bit register, CHECKSUM, that ensures certain very important

configuration registers maintain their desired value during

Normal Power Mode PSM0.

This no load condition is triggered when the absolute value

of phase apparent power is less than or equal to the threshold

indicated in the VANOLOAD 24-bit signed register. In this

case, the apparent energy of that phase is not accumulated

and no CFx pulses are generated based on this energy. The

VANOLOAD register represents the positive no load level

of apparent power relative to PMAX, the maximum apparent

The registers covered by this register are MASK0, MASK1,

COMPMODE, gain, CFMODE, CF1DEN, CF2DEN, CF3DEN,

CONFIG, MMODE, ACCMODE, LCYCMODE, HSDC_CFG,

and another six 8-bit reserved internal registers that always have

Rev. H | Page 65 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

default values. The ADE78xx computes the cyclic redundancy

check (CRC) based on the IEEE802.3 standard. The registers

are introduced one-by-one into a linear feedback shift register

(LFSR) based generator starting with the least significant bit (as

shown in Figure 82). The 32-bit result is written in the

CHECKSUM register. After power-up or a hardware/software

reset, the CRC is computed on the default values of the registers

giving the results presented in the Table 23.

g_i, i = 0, 1, 2, …, 31 are the coefficients of the generating

polynomial defined by the IEEE802.3 standard as follows:

G(x) = x³²+ x²⁶+ x²³+ x²²+ x¹⁶+ x¹²+ x¹¹+ x¹⁰+ x⁸+ x⁷+

x⁵+ x⁴+ x²+ x + 1

(49)

g₀= g₁= g₂= g₄= g₅= g₇= 1

g₈= g₁₀= g₁₁= g₁₂= g₁₆= g₂₂=g₂₃= g₂₆= 1

(50)

All of the other g_icoefficients are equal to 0.

FB(j) = a_{j – 1}XOR b₃₁(j – 1)

(51)

(52)

Table 23. Default Values of CHECKSUM and of Internal

Registers CRC

b₀(j) = FB(j) AND g₀

Default Value of

Part No. CHECKSUM

CRC of Internal

Registers

b_i(j) = FB(j) AND g_iXOR b_{i − 1}(j – 1), i = 1, 2, 3, ..., 31 (53)

Equation 51, Equation 52, and Equation 53 must be repeated for

j = 1, 2, …, 256. The value written into the CHECKSUM register

contains the Bit b_i(256), i = 0, 1, …, 31. The value of the CRC,

after the bits from the reserved internal register have passed

through LFSR, is obtained at Step j = 48 and is presented in the

Table 23.

ADE7854 0x44C48F8

ADE7858 0xD6744F93

ADE7868 0x93D774E6

ADE7878 0x33666787

0x391FBDDD

0x3E7D0FC1

0x23F7C7B1

0x2D32A389

Figure 83 shows how the LFSR works. The MASK0, MASK1,

COMPMODE, gain, CFMODE, CF1DEN, CF2DEN, CF3DEN,

CONFIG, MMODE, ACCMODE, LCYCMODE, and HSDC_CFG

registers, and the six 8-bit reserved internal registers form the

bits [a₂₅₅, a₂₅₄,…, a₀] used by LFSR. Bit a₀is the least significant

bit of the first internal register to enter LFSR; Bit a₂₅₅is the most

significant bit of the MASK0 register, the last register to enter

LFSR. The formulas that govern LFSR are as follows:

Two different approaches can be followed in using the CHECK-

SUM register. One is to compute the CRC based on the relations

(47) to (53) and then compare the value against the CHECKSUM

register. Another is to periodically read the CHECKSUM register.

If two consecutive readings differ, it can be assumed that one of

the registers has changed value and therefore, the ADE7854,

ADE7858, ADE7868, or ADE7878 has changed configuration.

The recommended response is to initiate a hardware/software

reset that sets the values of all registers to the default, including

the reserved ones, and then reinitialize the configuration registers.

b_i(0) = 1, i = 0, 1, 2, …, 31, the initial state of the bits that form

the CRC. Bit b₀is the least significant bit, and Bit b₃₁is the most

significant.

7

0

7

0

7

0

7

0

7

0

7

0

31

0

31

0

15

0 15 0 15

0

INTERNAL INTERNAL

INTERNAL

INTERNAL INTERNAL

MASK0 MASK1 COMPMODE GAIN CFMODE

REGISTER REGISTER REGISTER

255 248

240

232

224

216

40 32 24

16

8

7

0

LFSR

GENERATOR

Figure 82. CHECKSUM Register Calculation

g₀

g₁

g₂

g₃

g₃₁

FB

b₀

b₁

b₂

b₃₁

LFSR

a₂₅₅

,

a₂₅₄,....,a₂, a₁, a₀

Figure 83. LFSR Generator Used in CHECKSUM Register Calculation

1. To disable it, the bit must be cleared to 0. Two 32-bit status

registers, STATUS0 and STATUS1, are associated with the inter-

rupts. When an interrupt event occurs in the ADE78xx, the

corresponding flag in the interrupt status register is set to a Logic 1

(see Table 37 and Table 38). If the mask bit for this interrupt in

INTERRUPTS

The ADE7854/ADE7858/ADE7868/ADE7878 have two interrupt

IRQ0 IRQ1

pins,

and

. Each of the pins is managed by a 32-bit

interrupt mask register, MASK0 and MASK1, respectively. To

enable an interrupt, a bit in the MASKx register must be set to

IRQx

the interrupt mask register is Logic 1, then the

Rev. H | Page 66 of 100

logic output

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

goes active low. The flag bits in the interrupt status register are set

irrespective of the state of the mask bits. To determine the source

of the interrupt, the MCU should perform a read of the corres-

ponding STATUSx register and identify which bit is set to 1. To

erase the flag in the status register, write back to the STATUSx

register with the flag set to 1. After an interrupt pin goes low, the

status register is read and the source of the interrupt is identified.

Then, the status register is written back without any change to

When the STATUSx register is read and one of these bits is set

to 1, the status register associated with the bit is immediately

read to identify the phase that triggered the interrupt and only

at that time can the STATUSx register be written back with the bit

set to 1.

Using the Interrupts with an MCU

Figure 84 shows a timing diagram that illustrates a suggested

implementation of the ADE7854/ADE7858/ADE7868/ADE7878

IRQx

clear the status flag to 0. The

status flag is cancelled.

pin remains low until the

IRQx

interrupt management using an MCU. At Time t₁, the

goes active low indicating that one or more interrupt events

have occurred in the ADE78xx, at which point the following

steps should be taken:

By default, all interrupts are disabled. However, the RSTDONE

interrupt is an exception. This interrupt can never be masked

(disabled) and, therefore, Bit 15 (RSTDONE) in the MASK1

IRQx

1. Tie the

pin to a negative-edge-triggered external

IRQ1

register does not have any functionality. The

pin always

interrupt on the MCU.

goes low, and Bit 15 (RSTDONE) in the STATUS1 register is set

to 1 whenever a power-up or a hardware/software reset process

ends. To cancel the status flag, the STATUS1 register has to be

written with Bit 15 (RSTDONE) set to 1.

2. On detection of the negative edge, configure the MCU to

start executing its interrupt service routine (ISR).

3. On entering the ISR, disable all interrupts using the global

interrupt mask bit. At this point, the MCU external interrupt

flag can be cleared to capture interrupt events that occur

during the current ISR.

4. When the MCU interrupt flag is cleared, a read from

STATUSx, the interrupt status register, is carried out. The

interrupt status register content is used to determine the

source of the interrupt(s) and, hence, the appropriate

action to be taken.

Certain interrupts are used in conjunction with other status

registers. The following bits in the MASK1 register work in

conjunction with the status bits in the PHNOLOAD register:

•

Bit 0 (NLOAD)

Bit1 (FNLOAD), available in the ADE7878 only

Bit 2 (VANLOAD)

The following bits in the MASK1 register work with the status bits

in the PHSTATUS register:

5. The same STATUSx content is written back into the

IRQx

ADE78xx to clear the status flag(s) and reset the

to logic high (t₂).

line

•

Bit 16, (SAG)

Bit 17 (OI)

Bit 18 (OV)

If a subsequent interrupt event occurs during the ISR (t₃), that

event is recorded by the MCU external interrupt flag being set

again.

The following bits in the MASK1 register work with the status bits

in the IPEAK and VPEAK registers, respectively:

On returning from the ISR, the global interrupt mask bit is

cleared (same instruction cycle) and the external interrupt flag

uses the MCU to jump to its ISR once again. This ensures that

the MCU does not miss any external interrupts.

•

Bit 23 (PKI)

Bit 24 (PKV)

Figure 85 shows a recommended timing diagram when the

status bits in the STATUSx registers work in conjunction with

The following bits in the MASK0 register work with the status bits

in the PHSIGN register:

IRQx

bits in other registers. When the

pin goes active low, the

•

Bits[6:8] (REVAPx)

Bits[10:12] (REVRPx), available in the ADE7858,

ADE7868, and ADE7878 only

STATUSx register is read, and if one of these bits is 1, a second

•

Bit 9, Bit 13, and Bit 18 (REVPSUMx)

Rev. H | Page 67 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

MCU

INTERRUPT

FLAG SET

t₁

t₂

t₃

IRQx

WRITE

GLOBAL

INTERRUPT

MASK

ISR RETURN

GLOBAL INTERRUPT

MASK RESET

CLEAR MCU

INTERRUPT

FLAG

READ

STATUSx

JUMP

TO ISR

PROGRAM

SEQUENCE

ISR ACTION

(BASED ON STATUSx CONTENTS)

JUMP

TO ISR

BACK

STATUSx

Figure 84. Interrupt Management

MCU

INTERRUPT

FLAG SET

t₁

t₂

t₃

IRQx

WRITE

GLOBAL

INTERRUPT

MASK

ISR RETURN

GLOBAL INTERRUPT

MASK RESET

CLEAR MCU

INTERRUPT

FLAG

READ

STATUSx

JUMP

TO ISR

PROGRAM

SEQUENCE

READ

PHx

ISR ACTION

(BASED ON STATUSx CONTENTS)

JUMP

TO ISR

BACK

STATUSx

Figure 85. Interrupt Management when PHSTATUS, IPEAK, VPEAK, or PHSIGN Registers are Involved

status register is read immediately to identify the phase that

triggered the interrupt. The name, PHx, in Figure 85 denotes

one of the PHSTATUS, IPEAK, VPEAK, or PHSIGN registers.

Then, STATUSx is written back to clear the status flag(s).

After the serial port choice is completed, it needs to be locked.

Consequently, the active port remains in use until a hardware

reset is executed in PSM0 normal mode or until a power-down.

If I²C is the active serial port, Bit 1 (I2C_LOCK) of the CONFIG2

register must be set to 1 to lock it in. From this moment, the

ADE7854/ADE7858/ADE7868/ADE7878 ignore spurious

SERIAL INTERFACES

The ADE7854/ADE7858/ADE7868/ADE7878 have three serial

port interfaces: one fully licensed I²C interface, one serial

peripheral interface (SPI), and one high speed data capture port

(HSDC). As the SPI pins are multiplexed with some of the pins

of the I²C and HSDC ports, the ADE78xx accepts two confi-

gurations: one using the SPI port only and one using the I²C

port in conjunction with the HSDC port.

SS

toggling of the pin and an eventual switch into using the SPI

port is no longer possible. If the SPI is the active serial port, any

write to the CONFIG2 register locks the port. From this moment,

a switch into using the I²C port is no longer possible. Once locked,

the serial port choice is maintained when the ADE78xx changes

PSMx power modes.

The functionality of the ADE78xx is accessible via several on-

chip registers. The contents of these registers can be updated or

read using either the I²C or SPI interfaces. The HSDC port provides

the state of up to 16 registers representing instantaneous values of

phase voltages and neutral currents, and active, reactive, and

apparent powers.

Serial Interface Choice

After reset, the HSDC port is always disabled. Choose between

2

SS

the I C and SPI ports by manipulating the /HSA pin after

SS

power-up or after a hardware reset. If the /HSA pin is kept

high, then the ADE7854/ADE7858/ADE7868/ADE7878 use the

2

SS

I²C-Compatible Interface

I C port until a new hardware reset is executed. If the /HSA

pin is toggled high to low three times after power-up or after a

hardware reset, the ADE7854/ADE7858/ADE7868/ADE7878

use the SPI port until a new hardware reset is executed. This

The ADE7854/ADE7858/ADE7868/ADE7878 supports a fully

licensed I²C interface. The I²C interface is implemented as a full

hardware slave. SDA is the data I/O pin, and SCL is the serial

clock. These two pins are shared with the MOSI and SCLK pins

of the on-chip SPI interface. The maximum serial clock frequency

supported by this interface is 400 kHz.

SS

manipulation of the /HSA pin can be accomplished in two

SS

ways. First, use the /HSA pin of the master device (that is, the

microcontroller) as a regular I/O pin and toggle it three times.

Second, execute three SPI write operations to a location in the

address space that is not allocated to a specific ADE78xx register

(for example 0xEBFF, where eight bit writes can be executed).

The two pins used for data transfer, SDA and SCL, are confi-

gured in a wire-AND’e d format that allows arbitration in a

multimaster system.

The transfer sequence of an I²C system consists of a master device

initiating a transfer by generating a start condition while the bus

is idle. The master transmits the address of the slave device and

the direction of the data transfer in the initial address transfer. If

the slave acknowledges, the data transfer is initiated. This con-

tinues until the master issues a stop condition, and the bus

becomes idle.

SS

These writes allow the /HSA pin to toggle three times. See the

SPI Write Operation section for details on the write protocol

involved.

Rev. H | Page 68 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

I²C Write Operation

read/

bit. Because this is a write operation, it has to be

cleared to 0; therefore, the first byte of the write operation is

0x70. After every byte is received, the ADE7854/ADE7858/

ADE7868/ADE7878 generate an acknowledge. As registers can

have 8, 16, or 32 bits, after the last bit of the register is transmitted

and the ADE78xx acknowledges the transfer, the master gene-

rates a stop condition. The addresses and the register content

are sent with the most significant bit first. See Figure 86 for

details of the I²C write operation.

write

The write operation using the I²C interface of the ADE7854/

ADE7858/ADE7868/ADE7878 initiate when the master generates

a start condition and consists in one byte representing the

address of the ADE78xx followed by the 16-bit address of the

target register and by the value of the register.

The most significant seven bits of the address byte constitute

the address of the ADE7854/ADE7858/ADE7868/ADE7878

and they are equal to 0111000b. Bit 0 of the address byte is a

15

8

7

0

31

24

23

16

15

8

7

0

S

0

1

0

S

MSB 8 BITS OF

REGISTER ADDRESS

LSB 8 BITS OF

REGISTER ADDRESS

BYTE 3 (MSB)

OF REGISTER

BYTE 0 (LSB) OF

REGISTER

A

C

K

A

C

K

A

C

K

A

C

K

A

C

K

A

C

K

A

C

K

BYTE 2 OF REGISTER

BYTE 1 OF REGISTER

SLAVE ADDRESS

ACKNOWLEDGE

GENERATED BY

ADE78xx

Figure 86. I²C Write Operation of a 32-Bit Register

Rev. H | Page 69 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

I²C Read Operation

ADE7854/ADE7858/ADE7868/ADE7878, the second stage

begins with the master generating a new start condition followed

by an address byte. The most significant seven bits of this address

byte constitute the address of the ADE78xx, and they are equal to

The read operation using the I²C interface of the ADE7854/

ADE7858/ADE7868/ADE7878 is accomplished in two stages.

The first stage sets the pointer to the address of the register. The

second stage reads the content of the register.

write

0111000b. Bit 0 of the address byte is a read/

bit. Because this

is a read operation, it must be set to 1; thus, the first byte of the

read operation is 0x71. After this byte is received, the ADE78xx

generates an acknowledge. Then, the ADE78xx sends the value

of the register, and after every eight bits are received, the master

generates an acknowledge. All the bytes are sent with the most

significant bit first. Because registers can have 8, 16, or 32 bits,

after the last bit of the register is received, the master does not

acknowledge the transfer but generates a stop condition.

As seen in Figure 87, the first stage initiates when the master

generates a start condition and consists in one byte representing

the address of the ADE7854/ADE7858/ADE7868/ADE7878

followed by the 16-bit address of the target register. The ADE78xx

acknowledges every byte received. The address byte is similar to

the address byte of a write operation and is equal to 0x70 (see

the I2C Write Operation section for details). After the last byte

of the register address has been sent and acknowledged by the

15

8

7

0

S

0 1 1 1 0 0 0 0

A

C

K

A

C

K

A

C

K

MSB 8 BITS OF

REGISTER ADDRESS

LSB 8 BITS OF

REGISTER ADDRESS

SLAVE ADDRESS

ACKNOWLEDGE

GENERATED BY

ADE78xx

ACKNOWLEDGE

GENERATED BY

MASTER

N

O

A

C

K

A

C

K

A

C

K

C

K

31

24

23

16

15

8

7

0

S

0

1

0

1

S

A

C

K

BYTE 3 (MSB)

OF REGISTER

BYTE 2 OF

REGISTER

BYTE 1 OF

REGISTER

BYTE 0 (LSB)

OF REGISTER

SLAVE ADDRESS

ACKNOWLEDGE

GENERATED BY

ADE78xx

Figure 87. I²C Read Operation of a 32-Bit Register

Rev. H | Page 70 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

SPI-Compatible Interface

SPI DEVICE

MOSI

ADE78xx

The SPI of the ADE7854/ADE7858/ADE7868/ADE7878 is

always a slave of the communication and consists of four pins

(with dual functions): SCLK/SCL, MOSI/SDA, MISO/HSD, and

MOSI/SDA

MISO/HSD

SCLK/SCL

SS/HSA

MISO

SCK

SS

/HSA. The functions used in the SPI-compatible interface are

SS

SCLK, MOSI, MISO, and . The serial clock for a data transfer

is applied at the SCLK logic input. All data transfer operations

synchronize to the serial clock. Data shifts into the ADE78xx at

the MOSI logic input on the falling edge of SCLK and the

ADE78xx samples it on the rising edge of SCLK. Data shifts out

of the ADE7854/ADE7858/ADE7868/ADE7878 at the MISO

logic output on a falling edge of SCLK and can be sampled by

the master device on the raising edge of SCLK. The most

significant bit of the word is shifted in and out first. The

maximum serial clock frequency supported by this interface is

2.5 MHz. MISO stays in high impedance when no data is

transmitted from the ADE7854/ADE7858/ADE7868/ADE7878.

See Figure 88 for details of the connection between the

ADE78xx SPI and a master device containing an SPI interface.

Figure 88. Connecting ADE78xx SPI with an SPI Device

SPI Read Operation

The read operation using the SPI interface of the ADE7854/

ADE7858/ADE7868/ADE7878 initiate when the master sets the

SS

/HSA pin low and begins sending one byte, representing the

address of the ADE7854/ADE7858/ADE7868/ADE7878, on the

MOSI line. The master sets data on the MOSI line starting with

the first high-to-low transition of SCLK. The SPI of the ADE78xx

samples data on the low-to-high transitions of SCLK. The most

significant seven bits of the address byte can have any value, but

as a good programming practice, they should be different from

0111000b, the seven bits used in the I C protocol. Bit 0 (read/

2

write

)

of the address byte must be 1 for a read operation. Next, the

master sends the 16-bit address of the register that is read. After

the ADE78xx receives the last bit of address of the register on a

low-to-high transition of SCLK, it begins to transmit its contents

on the MISO line when the next SCLK high-to-low transition

occurs; thus, the master can sample the data on a low-to-high

SCLK transition. After the master receives the last bit, it sets the

SS

The logic input is the chip select input. This input is used

SS

when multiple devices share the serial bus. Drive the input

SS

low for the entire data transfer operation. Bringing high

during a data transfer operation aborts the transfer and places

the serial bus in a high impedance state. A new transfer can

SS

then be initiated by returning the logic input to low. However,

SS

and SCLK lines high and the communication ends. The data

because aborting a data transfer before completion leaves the

accessed register in a state that cannot be guaranteed, every

time a register is written, its value should be verified by reading

it back. The protocol is similar to the protocol used in I²C

interface.

lines, MOSI and MISO, go into a high impedance state. See

Figure 89 for details of the SPI read operation.

SS

SCLK

15 14

1 0

MOSI

REGISTER ADDRESS

0

0 0 0 0 0 0 1

31 30

1 0

MISO

REGISTER VALUE

Figure 89. SPI Read Operation of a 32-Bit Register

Rev. H | Page 71 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

2

write

) of the

SPI Write Operation

seven bits used in the I C protocol. Bit 0 (read/

address byte must be 0 for a write operation. Next, the master

sends both the 16-bit address of the register that is written and

the 32-, 16-, or 8-bit value of that register without losing any

SCLK cycle. After the last bit is transmitted, the master sets the

The write operation using the SPI interface of the ADE78xx

SS

initiates when the master sets the /HSA pin low and begins

sending one byte representing the address of the ADE7854/

ADE7858/ADE7868/ADE7878 on the MOSI line. The master

sets data on the MOSI line starting with the first high-to-low

transition of SCLK. The SPI of the ADE78xx samples data on

the low-to-high transitions of SCLK. The most significant seven

bits of the address byte can have any value, but as a good pro-

gramming practice, they should be different from 0111000b, the

SS

and SCLK lines high at the end of the SCLK cycle and the

communication ends. The data lines, MOSI and MISO, go into

a high impedance state. See Figure 90 for details of the SPI write

operation.

SS

SCLK

15 14

1

0

31 30

1 0

MOSI

REGISTER ADDRESS

REGISTER VALUE

0

0 0 0 0 0 0 0

Figure 90. SPI Write Operation of a 32-Bit Register

Rev. H | Page 72 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

HSDC Interface

Bit 0 (HCLK) in the HSDC_CFG register determines the serial

clock frequency of the HSDC communication. When HCLK is

0 (the default value), the clock frequency is 8 MHz. When HCLK

is 1, the clock frequency is 4 MHz. A bit of data is transmitted

for every HSCLK high-to-low transition. The slave device that

receives data from HSDC samples the HSD line on the low-to-

high transition of HSCLK.

The high speed data capture (HSDC) interface is disabled after

default. It can be used only if the ADE7854/ADE7858/ADE7868/

ADE7878 is configured with an I²C interface. The SPI interface

of the ADE7854/ADE7858/ADE7868/ADE7878 cannot be used

simultaneously with HSDC.

Bit 6 (HSDCEN) in the CONFIG register activates HSDC when

set to 1. If Bit HSDCEN is cleared to 0, the default value, the

HSDC interface is disabled. Setting Bit HSDCEN to 1 when SPI

is in use does not have any effect. HSDC is an interface for

sending to an external device (usually a microprocessor or a

DSP) up to sixteen 32-bit words. The words represent the

instantaneous values of the phase currents and voltages, neutral

current, and active, reactive, and apparent powers. The registers

being transmitted include IAWV, VAWV, IBWV, VBWV, ICWV,

VCWV, INWV, AVA, BVA, CVA, AWATT, BWATT, CWATT,

AVAR, BVAR, and CVAR. All are 24-bit registers that are sign

extended to 32-bits (see Figure 37 for details). In the case of

ADE7854 and ADE7858, the INWV register is not available. In

its place, the HSDC transmits one 32-bit word always equal

to 0. In addition, the AVAR, BVAR, and CVAR registers are not

available in the ADE7854. In their place, the HSDC transmits

three 32-bit words that are always equal to 0.

The words can be transmitted as 32-bit packages or as 8-bit

packages. When Bit 1 (HSIZE) in the HSDC_CFG register is 0 (the

default value), the words are transmitted as 32-bit packages. When

Bit HSIZE is 1, the registers are transmitted as 8-bit packages. The

HSDC interface transmits the words MSB first.

Bit 2 (HGAP) introduces a gap of seven HSCLK cycles between

packages when Bit 2 (HGAP) is set to 1. When Bit HGAP is cleared

to 0 (the default value), no gap is introduced between packages

and the communication time is shortest. In this case, HSIZE

does not have any influence on the communication and a data

bit is placed on the HSD line with every HSCLK high-to-low

transition.

Bits[4:3] (HXFER[1:0]) decide how many words are transmitted.

When HXFER[1:0] is 00, the default value, then all 16 words are

transmitted. When HXFER[1:0] is 01, only the words representing

the instantaneous values of phase and neutral currents and phase

voltages are transmitted in the following order: IAWV, VAWV,

IBWV, VBWV, ICWV, VCWV, and one 32-bit word that is always

equal to INWV. When HXFER[1:0] is 10, only the instantaneous

values of phase powers are transmitted in the following order:

AVA, BVA, CVA, AWATT, BWATT, CWATT, AVAR, BVAR, and

CVAR. The value, 11, for HXFER[1:0] is reserved and writing it is

equivalent to writing 00, the default value.

HSDC can be interfaced with SPI or similar interfaces. HSDC is

always a master of the communication and consists of three

pins: HSA, HSD, and HSCLK. HSA represents the select signal.

It stays active low or high when a word is transmitted and it is

usually connected to the select pin of the slave. HSD sends data

to the slave and it is usually connected to the data input pin of

the slave. HSCLK is the serial clock line that is generated by the

ADE7854/ADE7858/ADE7868/ADE7878 and it is usually con-

nected to the serial clock input of the slave. Figure 91 shows the

connections between the ADE78xx HSDC and slave devices

containing an SPI interface.

Bit 5 (HSAPOL) determines the polarity of HSA function of the

SS

/HSA pin during communication. When HSAPOL is 0 (the

default value), HSA is active low during the communication.

This means that HSA stays high when no communication is in

progress. When a communication is executed, HSA is low when

the 32-bit or 8-bit packages are transferred, and is high during

SPI DEVICE

MISO

ADE78xx

MISO/HSD

SS

the gaps. When HSAPOL is 1, the HSA function of the /HSA

CF3/HSCLK

SS/HSA

SCK

SS

pin is active high during the communication. This means that

HSA stays low when no communication is in progress. When a

communication is executed, HSA is high when the 32-bit or

8-bit packages are transferred, and is low during the gaps.

Figure 91. Connecting the ADE78xx HSDC with an SPI

The HSDC communication is managed by the HSDC_CFG

register (see Table 53). It is recommended to set the HSDC_CFG

register to the desired value before enabling the port using Bit 6

(HSDCEN) in the CONFIG register. In this way, the state of

various pins belonging to the HSDC port do not take levels incon-

sistent with the desired HSDC behavior. After a hardware reset

Bits[7:6] of the HSDC_CFG register are reserved. Any value

written into these bits does not have any consequence on HSDC

behavior.

Figure 92 shows the HSDC transfer protocol for HGAP = 0,

HXFER[1:0] = 00 and HSAPOL = 0. Note that the HSDC

interface sets a data bit on the HSD line every HSCLK high-

to-low transition and the value of Bit HSIZE is irrelevant.

SS

or after power-up, the MISO/HSD and /HSA pins are set high.

Rev. H | Page 73 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Figure 93 shows the HSDC transfer protocol for HSIZE = 0,

HGAP = 1, HXFER[1:0] = 00, and HSAPOL = 0. Note that the

HSDC interface introduces a seven-HSCLK cycles gap between

every 32-bit word.

Table 24 lists the time it takes to execute an HSDC data transfer

for all HSDC_CFG register settings. For some settings, the

transfer time is less than 125 μs (8 kHz), the waveform sample

registers update rate. This means the HSDC port transmits data

every sampling cycle. For settings in which the transfer time is

greater than 125 μs, the HSDC port transmits data only in the

first of two consecutive 8 kHz sampling cycles. This means it

transmits registers at an effective rate of 4 kHz.

Figure 94 shows the HSDC transfer protocol for HSIZE = 1,

HGAP = 1, HXFER[1:0] = 00, and HSAPOL = 0. Note that the

HSDC interface introduces a seven-HSCLK cycles gap between

every 8-bit word.

See Table 53 for the HSDC_CFG register and descriptions for

the HCLK, HSIZE, HGAP, HXFER[1:0], and HSAPOL bits.

Table 24. Communication Times for Various HSDC Settings

HXFER[1:0]

HGAP

HSIZE¹

HCLK

Communication Time (μs)

00

01

10

0

1

0

1

0

1

N/A

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

64

128

77.125

154.25

119.25

238.25

28

56

33.25

66.5

51.625

103.25

36

72

43

1

N/A

0

1

N/A

0

1

86

66.625

133.25

1

¹N/A means not applicable.

HSCLK

31

0

31

VAWV (32 BITS)

0

31

0

31

CVAR (32 BITS)

0

HSD

HSA

IAVW (32 BITS)

IBWV (32 BITS)

Figure 92. HSDC Communication for HGAP = 0, HXFER[1:0] = 00, and HSAPOL = 0; HSIZE Is Irrelevant

HSCLK

HSD

31

0

31

0

31

0

31

0

IAVW (32-BIT)

VAWV (32-BIT)

IBWV (32-BIT)

CVAR (32-BIT)

7 HCLK CYCLES

HSA

Figure 93. HSDC Communication for HSIZE = 0, HGAP = 1, HXFER[1:0] = 00, and HSAPOL = 0

Rev. H | Page 74 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

HSCLK

31

24

23

16

IAWV (BYTE 2)

15

IAWV (BYTE 1)

8

7

0

HSD

IAVW (BYTE 3)

CVAR (BYTE 0)

7 HCLK CYCLES

HSA

Figure 94. HSDC Communication for HSIZE = 1, HGAP = 1, HXFER[1:0] = 00, and HSAPOL = 0

ADE7858 and ADE7868 have an identical approach to the

decoupling capacitors, the crystal and its load capacitors.

QUICK SETUP AS ENERGY METER

An energy meter is usually characterized by the nominal

current I_n, nominal voltage V_n, nominal frequency f_n, and the

meter constant MC.

C3

4.7µF

C4

0.22µF

To quickly setup the ADE7878, execute the following steps:

C1

4.7µF

C2

0.22µF

C5

0.1µF

C6

10µF

1. Select the PGA gains in the phase currents, voltages, and

neutral current channels: Bits [2:0] (PGA1), Bits [5:3]

(PGA2) and Bits [8:6] (PGA3) in the Gain register.

2. If Rogowski coils are used, enable the digital integrators in

the phase and neutral currents: Bit 0 (INTEN) set to 1 in

CONFIG register.

24

5

26

U1

C7

C10

2

3

4

7

8

PM0

PM1

RESET

IAP

IAN

IBP

IBN

ICP

ICN

INP

0.1µF

4.7µF

17

28

REF

IN/OUT

CLKOUT

Y1

C8

20pF

2

29

32

9

R1

5MΩ

IRQ0

IRQ1

3. If f_n=60 Hz, set Bit 14 (SELFREQ) in COMPMODE

12

13

14

15

16

18

23

22

19

27

36

38

C9

20pF

1

register (ADE7878 only).

33

34

35

CF1

CF2

4. Initialize WTHR1 and WTHR0 registers based on

Equation 25. Make VARTHR1 (ADE7858, ADE7868, and

ADE7878 only) and VATHR1 equal to WTHR1 and

VARTHR0 (ADE7858, ADE7868, and ADE7878 only) and

VATHR0 equal to W THR0.

INN

VN

CF3/HSCLK

VAP

VBP

VCP

CLKIN

SCLK/SCL

MOSI/SDA

37

39

MISQ/HSD

SS/HSA

5. Initialize CF1DEN, CF2DEN, and CF3DEN based on

Equation 26.

NC

6. Initialize VLEVEL (ADE7878 only) and VNOM registers

based on Equation 21 and Equation 42.

7. Enable the data memory RAM protection by writing 0xAD

to an internal 8-bit register located at Address 0xE7FE

followed by a write of 0x80 to an internal 8-bit register

located at Address 0xE7E3.

ADE7878ACPZ

Figure 95. ADE7878 Crystal and Capacitors Connections

Figure 96 and Figure 97 present a proposed layout of a printed

circuit board (PCB) with two layers that have the components

placed only on the top of the board. Following these layout

guidelines will help in creating a low noise design with higher

immunity to EMC influences.

8. Start the DSP by setting Run=1.

9. Read the energy registers xWATTHR, xVARHR

(ADE7858, ADE7868, and ADE7878 only), xVAHR,

xFWATTHR, and xFVARHR (ADE7878 only) to erase

their content and start energy accumulation from a known

state.

10. Enable the CF1, CF2 and CF3 frequency converter outputs

by clearing bits 9, 10 and 11 (CF1DIS, CF2DIS, and

CF3DIS) to 0 in CFMODE register.

The VDD, AVDD, DVDD and REF_in/outpins have each two

decoupling capacitors, one of uF order and a ceramic one of

220nF or 100nF. These ceramic capacitors need to be placed the

closest the the ADE7878 as they decouple high frequency

noises, while the uF ones need to be placed in close proximity.

The crystal load capacitors need to be placed closest to the

ADE7878, while the crystal can be placed in close proximity.

LAYOUT GUIDELINES

Figure 95 presents a basic schematic of the ADE7878 together

with its surrounding circuitry: decoupling capacitors at pins

VDD, AVDD, DVDD and REF_in/out, the 16.384 MHz crystal and

its load capacitors. The rest of the pins are dependent on the

particular application and are not shown here. The ADE7854,

Rev. H | Page 75 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

shown in Figure 98. CL₁and CL₂denote the capacitances of the

ceramic capacitors attached to the crystal pins, whereas CP₁and

CP₂denote the parasitic capacitances on those pins.

The recommended typical value of total capacitance at each

clock pin, CLKIN and CLKOUT, is 24 pF, which means that

Total Capacitance = CP₁+ CL₁= CP₂+ CL₂= 24 pF

Crystal manufacturer data sheets specify the load capacitance

value. A total capacitance of 24 pF, per clock pin, is recommended;

therefore, select a crystal with a 12 pF load capacitance. In

addition, when selecting the ceramic capacitors, CL₁and CL₂,

the parasitic capacitances, CP₁and CP₂, on the crystal pins of

the IC must be taken into account. Thus, the values of CL₁and

CL₂must be based on the following expression:

CL₁= CL₂= 2 × Crystal Load Capacitance − CP₁

where CP₁= CP₂.

For example, if a 12 pF crystal is chosen and the parasitic

capacitances on the clock pins are CP₁= CP₂= 2 pF, the ceramic

capacitors that must be used in the crystal circuit are CL₁= CL₂

= 22 pF.

Figure 96. ADE7878 Top Layer Printed Circuit Board

The exposed pad of the ADE7878 is soldered to an equivalent

pad on the PCB. The AGND and DGND traces of the ADE7878

are then routed directly into the PCB pad.

The Evaluation Board EVAL-ADE7878EBZ uses the crystal

VM6-1D11C12-TR-16.384MHZ (maximum drive level 1 mW;

maximum ESR 20 Ω; load capacitance 12 pF). It is recommended

that the same crystal, or a crystal with similar specifications, be

selected. Lower values of ESR and load capacitance and higher

values of drive level capability of the crystal are preferable.

The bottom layer is composed mainly of a ground plane

surrounding as much as possible the crystal traces.

It is also recommended that a 5 Mꢀ resistor be attached in

parallel to the crystal, as shown in Figure 98.

CL

2

GND

CLKIN

CP

2

5MΩ

ADE78xx IC

16.384MHz CRYSTAL

CP

1

CLKOUT

GND

CL

1

Figure 98. Crystal Circuit

ADE7878 EVALUATION BOARD

An evaluation board built upon the ADE7878 configuration

supports all ADE7854, ADE7858, ADE7868, and ADE7878

components. Visit www.analog.com/ADE7878 for details.

Figure 97. ADE7878 Bottom Layer Printed Circuit Board

DIE VERSION

The register named version identifies the version of the die. It is

an 8-bit, read-only version register located at Address 0xE707.

CRYSTAL CIRCUIT

A digital clock signal of 16.384 MHz can be provided to the

CLKIN pin of the ADE7854/ADE7858/ADE7868/ADE7878.

Alternatively, attach a crystal of the specified frequency, as

Rev. H | Page 76 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

SILICON ANOMALY

This anomaly list describes the known issues with the ADE7854, ADE7858, ADE7868, and ADE7878 silicon identified by the version

register (Address 0xE707) being equal to 2, to 4, and to 5.

Analog Devices, Inc., is committed, through future silicon revisions, to continuously improve silicon functionality. Analog Devices tries

to ensure that these future silicon revisions remain compatible with your present software/systems by implementing the recommended

workarounds outlined here.

ADE7854/ADE7858/ADE7868/ADE7878 FUNCTIONALITY ISSUES

Silicon Revision

Identifier

Chip Marking

ADE7854ACPZ

ADE7858ACPZ

ADE7868ACPZ

ADE7878ACPZ

ADE7854ACPZ

ADE7858ACPZ

ADE7868ACPZ

ADE7878ACPZ

ADE7854ACPZ

ADE7858ACPZ

ADE7868ACPZ

ADE7878ACPZ

Silicon Status

Anomaly Sheet

No. of Reported Issues

Version = 2

Released

Rev. A

4 (er001, er002, er003, er004)

Version = 4

Version = 5

Released

Rev. B

Rev. C

1 (er005)

FUNCTIONALITY ISSUES

Table 25. Offset RMS Registers Cannot be Set to Negative Values [er001, Version = 2 Silicon]

When the AIRMSOS, AVRMSOS, BIRMSOS, BVRMSOS, CIRMSOS, CVRMSOS, and NIRMSOS registers are set to a negative

value, for sufficiently small inputs, the argument of the square root used in the rms data path may become negative. In

this case, the corresponding AIRMS, AVRMS, BIRMS, BVRMS, CIRMS, or CVRMS rms register is automatically set to 0.

Background

Negative values for the AIRMSOS, AVRMSOS, BIRMSOS, BVRMSOS, CIRMSOS, CVRMSOS, and NIRMSOS registers are not

supported in the silicon version identified by the version register being equal to 2.

Issue

Do not use negative values for the AIRMSOS, AVRMSOS, BIRMSOS, BVRMSOS, CIRMSOS, CVRMSOS, and NIRMSOS

registers.

Workaround

If further details on this issue are required, please use the following website to submit your query:

www.analog.com/en/content/technical_support_page/fca.html.

None.

Related Issues

Rev. H | Page 77 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Table 26. Values Written to the CF1DEN, CF2DEN, CF3DEN, SAGLVL, and ZXTOUT Registers May Not Be Immediately Used By

ADE7854, ADE7858, ADE7868, ADE7878 [er002, Version = 2 Silicon]

Background

Usually, the CF1DEN, CF2DEN, CF3DEN, SAGLVL, and ZXTOUT registers initialize immediately after power-up or after a

hardware/software reset. After the RUN register is set to 1, the energy-to-frequency converter (for CF1DEN, CF2DEN, and CF3DEN), the

phase voltage sag detector (for SAGLVL), and the zero-crossing timeout circuit (for ZXTOUT) use these values immediately.

Issue

After the CF1DEN register is initialized with a new value after power-up or a hardware/software reset, the new value may be

delayed and, therefore, not immediately available for use by the energy-to-frequency converter. It is, however, used by the

converter after the first high-to-low transition is triggered at t the CF1 pin using the CF1DEN default value (0x0).

CF2DEN and CF3DEN registers present similar behavior at the CF2 and CF3 pins, respectively. CF1DEN, CF2DEN and CF3DEN

above behavior has been corrected in Version = 4 silicon.

After the SAGLVL register is initialized with a new value after power-up or a hardware or software reset, the new value may be

delayed and not available for immediate use by the phase voltage sag detector. However, it is used by the detector after at least

one phase voltage rises above 10% of the full-scale input at the phase voltage ADCs.

After the ZXTOUT register is initialized with a new value after power-up or a hardware or software reset, the new value may be

delayed and not available for immediate use by the zero-crossing timeout circuit. However, the circuit does use the new value

after at least one phase voltage rises above 10% of the full-scale input at the phase voltage ADCs.

Workaround

If the behavior outlined in the Issue row does not conflict with the meter specification, then the new values of the CF1DEN,

CF2DEN, CF3DEN, SAGLVL, and ZXTOUT registers may be written one time only.

If the behavior is not acceptable, write the new value into the CF1DEN, CF2DEN, and CF3DEN registers eight consecutive times.

This ensures the probability of the new value not being considered immediately by the energy-to-frequency converter becomes

lower than 0.2 ppm.

Usually, at least one of the phase voltages is greater than 10% of full scale after power-up or after a hardware/software reset. If

this cannot be guaranteed, then the SAGLVL and ZXTOUT registers should also be written eight consecutive times to reduce the

probability of not being considered immediately by the phase voltage sag detector and zero-crossing timeout circuit.

Related Issues None.

Table 27. The Read-Only RMS Registers May Show the Wrong Value [er003, Version = 2 Silicon]

Background

The read-only rms registers (AVRMS, BVRMS, CVRMS, AIRMS, BIRMS, CIRMS, and NIRMS) can be read without restrictions at

any time.

Issue

The fixed function DSP of ADE7854, ADE7858, ADE7868, and ADE7878 computes all the powers and rms values in a loop

with a period of 125 µs (8 kHz frequency). If two rms registers are accessed (read) consecutively, the value of the second

register may be corrupted. Consequently, the apparent power computed during that 125 µs cycle is also corrupted. The

rms calculation recovers in the next 125 µs cycle, and all the rms and apparent power values compute correctly.

The issue appears independent of the communication type, SPI or I²C, when the time between the start of two

consecutive rms readings is lower than 265 µs. The issue affects only the rms registers; all of the other registers of

ADE7854, ADE7858, ADE7868, and ADE7878 can be accessed without any restrictions.

Workaround

The rms registers can be read one at a time with at least 265 µs between the start of the readings. DREADY interrupt at the

IRQ0

pin can be used to time one rms register reading every three consecutive DREADY interrupts. This ensures 375 µs

between the start of the rms readings.

Alternatively, the rms registers can be read interleaved with readings of other registers that are not affected by this

restriction as long as the time between the start of two consecutive rms register readings is 265 μs.

None.

Related Issues

Table 28. To Obtain Best Accuracy Performance, Internal Setting Must Be Changed [er004, Version = 2 Silicon]

Internal default settings provide best accuracy performance for ADE7854, ADE7858, ADE7868, and ADE7878.

It was found that if a different setting is used, the accuracy performance can be improved.

To enable a new setting for this internal register, execute two consecutive 8-bit register write operations:

The first write operation: 0xAD is written to Address 0xE7FE.

Background

Issue

Workaround

The second write operation: 0x01 is written to Address 0xE7E2.

The write operations must be executed consecutively without any other read/write operation in between. As a

verification that the value was captured correctly, a simple 8-bit read of Address 0xE7E2 should show the 0x01 value.

None.

Related Issues

Rev. H | Page 78 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Table 29. Values Written to the SAGLVL and ZXTOUT Registers May Not Be Immediately Used by ADE7854, ADE7858,

ADE7868, and ADE7878 [er005, Version = 4 and Version = 5 Silicons]

Background

Usually, the SAGLVL and ZXTOUT registers initialize immediately after power-up or after a hardware/software reset. After

the run register is set to 1, the phase voltage sag detector (for SAGLVL), and the zero-crossing timeout circuit (for ZXTOUT)

use these values immediately.

Issue

After the SAGLVL register is initialized with a new value after power-up or a hardware or software reset, the new value

may be delayed and not available for immediate use by the phase voltage sag detector. However, it is used by the

detector after at least one phase voltage rises above 10% of the full-scale input at the phase voltage ADCs.

After the ZXTOUT register is initialized with a new value after power-up or a hardware or software reset, the new value

may be delayed and not available for immediate use by the zero-crossing timeout circuit. However, the circuit does use

the new value after at least one phase voltage rises above 10% of the full-scale input at the phase voltage ADCs.

Workaround

Usually, at least one of the phase voltages is greater than 10% of full scale after power-up or after a hardware/software

reset. If this cannot be guaranteed, then the SAGLVL and ZXTOUT registers should be written eight consecutive times to

reduce the probability of not being considered immediately by the phase voltage sag detector and zero-crossing timeout

circuit below 0.2 ppm.

None.

Related Issues

SECTION 1. ADE7854/ADE7858/ADE7868/ADE7878 FUNCTIONALITY ISSUES

Reference

Number

Description

Status

er001

er002

Offset rms registers cannot be set to negative values.

Values written to the CF1DEN, CF2DEN, CF2DEN, SAGLVL, and ZXTOUT registers may not be immediately

used by ADE7854, ADE7858, ADE7868, and ADE7878.

Identified

er003

er004

er005

The read-only rms registers may show the wrong value.

To obtain best accuracy performance, internal setting must be changed.

Values written to the SAGLVL and ZXTOUT registers may not be immediately used by ADE7854, ADE7858,

ADE7868, and ADE7878.

Identified

This completes the Silicon Anomaly section.

Rev. H | Page 79 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

REGISTERS LIST

Table 30. Registers List Located in DSP Data Memory RAM

Register

Name

Bit

Bit Length During

Default

Address

0x4380

0x4381

0x4382

0x4383

0x4384

0x4385

0x4386

R/W¹Length Communication²

Type ³Value

Description

AIGAIN

AVGAIN

BIGAIN

BVGAIN

CIGAIN

CVGAIN

NIGAIN

R/W

24

32 ZPSE

S

0x000000

Phase A current gain adjust.

Phase A voltage gain adjust.

Phase B current gain adjust.

Phase B voltage gain adjust.

Phase C current gain adjust.

Phase C voltage gain adjust.

Neutral current gain adjust (ADE7868 and

ADE7878 only).

0x4387

0x4388

0x4389

0x438A

0x438B

0x438C

0x438D

AIRMSOS

AVRMSOS

BIRMSOS

BVRMSOS

CIRMSOS

CVRMSOS

NIRMSOS

R/W

24

32 ZPSE

S

0x000000

Phase A current rms offset.

Phase A voltage rms offset.

Phase B current rms offset.

Phase B voltage rms offset.

Phase C current rms offset.

Phase C voltage rms offset.

Neutral current rms offset (ADE7868 and

ADE7878 only).

0x438E

0x438F

0x4390

0x4391

0x4392

0x4393

0x4394

0x4395

0x4396

0x4397

AVAGAIN

BVAGAIN

CVAGAIN

AWGAIN

AWATTOS

BWGAIN

BWATTOS

CWGAIN

CWATTOS

AVARGAIN

R/W

24

32 ZPSE

S

0x000000

Phase A apparent power gain adjust.

Phase B apparent power gain adjust.

Phase C apparent power gain adjust.

Phase A total active power gain adjust.

Phase A total active power offset adjust.

Phase B total active power gain adjust.

Phase B total active power offset adjust.

Phase C total active power gain adjust.

Phase C total active power offset adjust.

Phase A total reactive power gain adjust

(ADE7858, ADE7868, and ADE7878).

0x4398

0x4399

0x439A

0x439B

0x439C

0x439D

AVAROS

R/W

24

32 ZPSE

S

0x000000

Phase A total reactive power offset adjust

(ADE7858, ADE7868, and ADE7878).

Phase B total reactive power gain adjust

(ADE7858, ADE7868, and ADE7878).

Phase B total reactive power offset adjust

(ADE7858, ADE7868, and ADE7878).

Phase C total reactive power gain adjust

(ADE7858, ADE7868, and ADE7878).

Phase C total reactive power offset adjust

(ADE7858, ADE7868, and ADE7878).

Phase A fundamental active power gain

adjust. Location reserved for ADE7854,

ADE7858, and ADE7868.

BVARGAIN

BVAROS

CVARGAIN

CVAROS

AFWGAIN

0x439E

AFWATTOS

R/W

24

32 ZPSE

S

0x000000

Phase A fundamental active power offset

adjust. Location reserved for ADE7854,

ADE7858, and ADE7868.

0x439F

0x43A0

0x43A1

0x43A2

BFWGAIN

BFWATTOS

CFWGAIN

CFWATTOS

R/W

24

32 ZPSE

S

0x000000

Phase B fundamental active power gain

adjust (ADE7878 only).

Phase B fundamental active power offset

adjust (ADE7878 only).

Phase C fundamental active power gain

adjust.

Phase C fundamental active power offset

adjust (ADE7878 only).

Rev. H | Page 80 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Register

Name

Bit

Bit Length During

Default

Address

R/W¹Length Communication²

Type ³Value

Description

0x43A3

AFVARGAIN

R/W

24

32 ZPSE

32 ZP

S

U

0x000000

Phase A fundamental reactive power gain

adjust (ADE7878 only).

Phase A fundamental reactive power

offset adjust (ADE7878 only).

Phase B fundamental reactive power gain

adjust (ADE7878 only).

Phase B fundamental reactive power

offset adjust (ADE7878 only).

Phase C fundamental reactive power gain

adjust (ADE7878 only).

Phase C fundamental reactive power

offset adjust (ADE7878 only).

Most significant 24 bits of VATHR[47:0]

threshold used in phase apparent power

datapath.

0x43A4

0x43A5

0x43A6

0x43A7

0x43A8

0x43A9

AFVAROS

BFVARGAIN

BFVAROS

CFVARGAIN

CFVAROS

VATHR1

0x43AA

0x43AB

0x43AC

0x43AD

VATHR0

WTHR1

WTHR0

VARTHR1

R/W

24

32 ZP

U

0x000000

Less significant 24 bits of VATHR[47:0]

threshold used in phase apparent power

datapath.

Most significant 24 bits of WTHR[47:0]

threshold used in phase total/fundamental

active power datapath.

Less significant 24 bits of WTHR[47:0]

threshold used in phase total/fundamental

active power datapath.

Most significant 24 bits of VARTHR[47:0]

threshold used in phase total/fundamental

reactive power datapath (ADE7858,

ADE7868, and ADE7878).

0x43AE

VARTHR0

R/W

24

32 ZP

U

0x000000

Less significant 24 bits of VARTHR[47:0]

threshold used in phase total/fundamental

reactive power datapath (ADE7858,

ADE7868, and ADE7878).

This memory location should be kept at

0x000000 for proper operation.

0x43AF

0x43B0

0x43B1

0x43B2

Reserved

N/A⁴

R/W

N/A⁴

24

N/A⁴

VANOLOAD

APNOLOAD

32 ZPSE

S

0x0000000 No load threshold in the apparent power

datapath.

0x0000000 No load threshold in the total/fundamental

active power datapath.

0x0000000 No load threshold in the total/fundamental

reactive power datapath. Location

reserved for ADE7854.

24

VARNOLOAD R/W

24

0x43B3

VLEVEL

R/W

24

32 ZPSE

S

0x000000

Register used in the algorithm that

computes the fundamental active and

reactive powers (ADE7878 only).

This location should not be written for

proper operation.

0x43B4

0x43B5

Reserved

DICOEFF

N/A⁴

R/W

N/A⁴

24

N/A⁴

S

0x000000

32 ZPSE

0x0000000 Register used in the digital integrator

algorithm. If the integrator is turned on, it

must be set at 0xFF8000. In practice, it is

transmitted as 0xFFF8000.

0x43B6

0x43B7

0x43B8

HPFDIS

R/W

N/A⁴

R/W

24

32 ZP

N/A⁴

U

0x000000

Disables/enables the HPF in the current

datapath (see Table 34).

This memory location should be kept at

0x000000 for proper operation.

Threshold used in comparison between

the sum of phase currents and the neutral

current (ADE7868 and ADE7878 only).

Reserved

ISUMLVL

N/A⁴

24

N/A⁴

S

32 ZPSE

Rev. H | Page 81 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Register

Name

Bit

Bit Length During

Default

Address

R/W¹Length Communication²

Type ³Value

Description

0x43B9 to Reserved

0x43BE

N/A⁴

0x000000

These memory locations should be kept

at 0x000000 for proper operation.

Sum of IAWV, IBWV, and ICWV registers

(ADE7868 and ADE7878 only).

0x43BF

ISUM

R

28

32 ZP

S

N/A⁴

0x43C0

0x43C1

0x43C2

0x43C3

0x43C4

0x43C5

0x43C6

AIRMS

AVRMS

BIRMS

BVRMS

CIRMS

CVRMS

NIRMS

R

24

32 ZP

S

N/A⁴

Phase A current rms value.

Phase A voltage rms value.

Phase B current rms value.

Phase B voltage rms value.

Phase C current rms value.

Phase C voltage rms value.

Neutral current rms value (ADE7868 and

ADE7878 only).

These memory locations should not be

written for proper operation.

0x43C7 to Reserved

0x43FF

N/A⁴

¹R is read, and W is write.

²32 ZPSE = 24-bit signed register that is transmitted as a 32-bit word with four MSBs padded with 0s and sign extended to 28 bits. Whereas 32 ZP = 28- or 24-bit signed

or unsigned register that is transmitted as a 32-bit word with four MSBs or eight MSBs, respectively, padded with 0s.

³U is unsigned register, and S is signed register in twos complement format.

⁴N/A means not applicable.

Table 31. Internal DSP Memory RAM Registers

Bit Length

Register

Address Name

Bit

During

Default

R/W¹Length Communication

Type²Value

Description

0xE203

Reserved R/W

16

U

0x0000

This memory location should not be written for

proper operation.

Run register starts and stops the DSP. See the

Digital Signal Processor section for more details.

0xE228

Run R/W

U

0x0000

¹R is read, and W is write.

²U is unsigned register, and S is signed register in twos complement format.

Table 32. Billable Registers

Bit Length

During

Register

Address Name

Bit

Default

R/W^{1, 2}Length²Communication²Type^{2, 3}Value

Description

0xE400

0xE401

0xE402

0xE403

AWATTHR

BWATTHR

CWATTHR

AFWATTHR

R

32

S

0x00000000 Phase A total active energy accumulation.

0x00000000 Phase B total active energy accumulation.

0x00000000 Phase C total active energy accumulation.

0x00000000 Phase A fundamental active energy

accumulation (ADE7878 only).

0xE404

0xE405

0xE406

0xE407

0xE408

0xE409

0xE40A

0xE40B

BFWATTHR

CFWATTHR

AVARHR

R

32

S

0x00000000 Phase B fundamental active energy

accumulation (ADE7878 only).

0x00000000 Phase C fundamental active energy

accumulation (ADE7878 only).

0x00000000 Phase A total reactive energy accumulation

(ADE7858, ADE7868, and ADE7878 only).

0x00000000 Phase B total reactive energy accumulation

(ADE7858, ADE7868, and ADE7878 only).

0x00000000 Phase C total reactive energy accumulation

(ADE7858, ADE7868, and ADE7878 only).

0x00000000 Phase A fundamental reactive energy

accumulation (ADE7878 only).

0x00000000 Phase B fundamental reactive energy

accumulation (ADE7878 only).

0x00000000 Phase C fundamental reactive energy

accumulation (ADE7878 only).

BVARHR

CVARHR

AFVARHR

BFVARHR

CFVARHR

Rev. H | Page 82 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Bit Length

During

Register

Address Name

Bit

Default

R/W^{1, 2}Length²Communication²Type^{2, 3}Value

Description

0xE40C

0xE40D

0xE40E

AVAHR

BVAHR

CVAHR

R

32

S

0x00000000 Phase A apparent energy accumulation.

0x00000000 Phase B apparent energy accumulation.

0x00000000 Phase C apparent energy accumulation.

¹R is read, and W is write.

²N/A is not applicable.

³U is unsigned register, and S is signed register in twos complement format.

Table 33. Configuration and Power Quality Registers

Bit Length

Register

Name

Bit

Length

During

Default

Address

R/W¹

Communication²

Type³

Value⁴

Description

0xE500

IPEAK

R

32

U

N/A

Current peak register. See Figure 50

and Table 35 for details about its

composition.

0xE501

VPEAK

R

32

U

N/A

Voltage peak register. See Figure 50

and Table 36 for details about its

composition.

0xE502

0xE503

0xE504

STATUS0

STATUS1

AIMAV

R/W

R

32

20

32

32 ZP

U

N/A

Interrupt Status Register 0. See Table 37.

Interrupt Status Register 1. See Table 38.

Phase A current mean absolute value

computed during PSM0 and PSM1

modes (ADE7868 and ADE7878 only).

0xE505

0xE506

BIMAV

CIMAV

R

20

32 ZP

U

N/A

Phase B current mean absolute value

computed during PSM0 and PSM1

modes (ADE7868 and ADE7878 only).

Phase C current mean absolute value

computed during PSM0 and PSM1

modes (ADE7868 and ADE7878 only).

0xE507

0xE508

0xE509

0xE50A

0xE50B

0xE50C

0xE50D

0xE50E

0xE50F

OILVL

OVLVL

SAGLVL

MASK0

MASK1

IAWV

IBWV

ICWV

INWV

R/W

R

24

32

24

32 ZP

32

U

S

0xFFFFFF

0x000000

Overcurrent threshold.

Overvoltage threshold.

Voltage SAG level threshold.

0x00000000 Interrupt Enable Register 0. See Table 39.

0x00000000 Interrupt Enable Register 1. See Table 40.

N/A

32

32 SE

Instantaneous value of Phase A current.

Instantaneous value of Phase B current.

Instantaneous value of Phase C current.

Instantaneous value of neutral current

(ADE7868 and ADE7878 only).

0xE510

0xE511

0xE512

0xE513

VAWV

VBWV

VCWV

AWATT

R

24

32 SE

S

N/A

Instantaneous value of Phase A voltage.

Instantaneous value of Phase B voltage.

Instantaneous value of Phase C voltage.

Instantaneous value of Phase A total

active power.

0xE514

0xE515

0xE516

BWATT

CWATT

AVAR

R

24

32 SE

S

N/A

Instantaneous value of Phase B total

active power.

Instantaneous value of Phase C total

active power.

Instantaneous value of Phase A total

reactive power (ADE7858, ADE7868,

and ADE7878 only).

0xE517

0xE518

BVAR

CVAR

R

24

32 SE

S

N/A

Instantaneous value of Phase B total

reactive power (ADE7858, ADE7868,

and ADE7878 only).

Instantaneous value of Phase C total

reactive power (ADE7858, ADE7868,

and ADE7878 only).

Rev. H | Page 83 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Bit Length

Register

Name

Bit

Length

During

Default

Value⁴

Address

R/W¹

Communication²

Type³

Description

0xE519

AVA

R

24

32

24

32 SE

32

S

N/A

Instantaneous value of Phase A

apparent power.

Instantaneous value of Phase B

apparent power.

Instantaneous value of Phase C

apparent power.

0xE51A

0xE51B

0xE51F

0xE520

BVA

R

S

U

S

CVA

R

CHECKSUM

VNOM

R

0x33666787 Checksum verification. See the

Checksum Register section for details.

0x000000

R/W

32 ZP

Nominal phase voltage rms used in the

alternative computation of the

apparent power. When the VNOMxEN

bit is set, the applied voltage input in

the corresponding phase is ignored

and all corresponding rms voltage

instances are replaced by the value in

the VNOM register.

0xE521 to

0xE52E

Reserved

These addresses should not be written

for proper operation.

0xE600

0xE601

PHSTATUS

ANGLE0

R

16

U

N/A

Phase peak register. See Table 41.

Time Delay 0. See the Time Interval

Between Phases section for details.

0xE602

0xE603

ANGLE1

ANGLE2

Reserved

R

16

U

N/A

Time Delay 1. See the Time Interval

Between Phases section for details.

Time Delay 2. See the Time Interval

Between Phases section for details.

These addresses should not be written

for proper operation.

0xE604 to

0xE606

0xE607

0xE608

0xE609 to

0xE60B

PERIOD

PHNOLOAD

Reserved

R

16

U

N/A

Network line period.

Phase no load register. See Table 42.

These addresses should not be written

for proper operation.

0xE60C

0xE60D

0xE60E

LINECYC

ZXTOUT

COMPMODE R/W

R/W

16

U

0xFFFF

0x01FF

Line cycle accumulation mode count.

Zero-crossing timeout count.

Computation-mode register. See

Table 43.

0xE60F

0xE610

0xE611

0xE612

0xE613

0xE614

Gain

R/W

16

10

16

16 ZP

U

S

0x0000

0x0E88

0x0000

PGA gains at ADC inputs. See Table 44.

CFx configuration register. See Table 45.

CF1 denominator.

CF2 denominator.

CF3 denominator.

CFMODE

CF1DEN

CF2DEN

CF3DEN

APHCAL

Phase calibration of Phase A. See

Table 46.

0xE615

0xE616

0xE617

0xE618

BPHCAL

CPHCAL

PHSIGN

CONFIG

R/W

R

10

16

16 ZP

16

S

U

0x0000

N/A

Phase calibration of Phase B. See Table 46.

Phase calibration of Phase C. See Table 46.

Power sign register. See Table 47.

ADE7878 configuration register. See

Table 48.

R/W

16

0x0000

0xE700

0xE701

0xE702

MMODE

R/W

8

U

0x1C

0x00

0x78

Measurement mode register.

See Table 49.

Accumulation mode register.

See Table 50.

Line accumulation mode behavior. See

Table 52.

ACCMODE

LCYCMODE

0xE703

0xE704

PEAKCYC

SAGCYC

R/W

8

U

0x00

Peak detection half line cycles.

SAG detection half line cycles.

Rev. H | Page 84 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Bit Length

Register

Name

Bit

Length

During

Default

Address

R/W¹

Communication²

Type³

Value⁴

Description

0xE705

CFCYC

R/W

8

U

0x01

Number of CF pulses between two

consecutive energy latches. See the

Synchronizing Energy Registers with

CFx Outputs section.

0xE706

0xE707

0xEBFF

HSDC_CFG

Version

Reserved

R/W

R

8

U

0x00

HSDC configuration register. See Table 53.

Version of die.

This address can be used in manipulating

the SS/HSA pin when SPI is chosen as

the active port. See the Serial Interfaces

section for details.

0xEC00

0xEC01

LPOILVL

R/W

8

U

0x07

0x00

Overcurrent threshold used during

PSM2 mode (ADE7868 and ADE7878

only). See Table 54 in which the register

is detailed.

Configuration register used during

PSM1 mode. See Table 55.

CONFIG2

¹R is read, and W is write.

²32 ZP = 24- or 20-bit signed or unsigned register that is transmitted as a 32-bit word with 8 or 12 MSBs, respectively, padded with 0s. 32 SE = 24-bit signed register that

is transmitted as a 32-bit word sign extended to 32 bits. 16 ZP = 10-bit unsigned register that is transmitted as a 16-bit word with six MSBs padded with 0s.

³U is unsigned register, and S is signed register in twos complement format.

⁴N/A is not applicable.

Table 34. HPFDIS Register (Address 0x43B6)

Bit

Location

Default

Value

Description

23:0

00000000

When HPFDIS = 0x00000000, then all high-pass filters in voltage and current channels are enabled. When the

register is set to any nonzero value, all high-pass filters are disabled.

Table 35. IPEAK Register (Address 0xE500)

Bit Location

Bit Mnemonic

IPEAKVAL[23:0]

IPPHASE[0]

IPPHASE[1]

IPPHASE[2]

Default Value

Description

23:0

24

25

26

31:27

0

These bits contain the peak value determined in the current channel.

When this bit is set to 1, Phase A current generated IPEAKVAL[23:0] value.

When this bit is set to 1, Phase B current generated IPEAKVAL[23:0] value.

When this bit is set to 1, Phase C current generated IPEAKVAL[23:0] value.

These bits are always 0.

00000

Table 36. VPEAK Register (Address 0xE501)

Bit Location

Bit Mnemonic

VPEAKVAL[23:0]

VPPHASE[0]

VPPHASE[1]

VPPHASE[2]

Default Value

Description

23:0

24

25

26

31:27

0

These bits contain the peak value determined in the voltage channel.

When this bit is set to 1, Phase A voltage generated VPEAKVAL[23:0] value.

When this bit is set to 1, Phase B voltage generated VPEAKVAL[23:0] value.

When this bit is set to 1, Phase C voltage generated VPEAKVAL[23:0] value.

These bits are always 0.

00000

Table 37. STATUS0 Register (Address 0xE502)

Bit

Location Bit Mnemonic Default Value

Description

0

1

AEHF

0

When this bit is set to 1, it indicates that Bit 30 of any one of the total active energy

registers (AWATTHR, BWATTHR, or CWATTHR) has changed.

FAEHF

0

When this bit is set to 1, it indicates that Bit 30 of any one of the fundamental active

energy registers, FWATTHR, BFWATTHR, or CFWATTHR, has changed. This bit is always 0

for ADE7854, ADE7858, and ADE7868.

2

REHF

0

When this bit is set to 1, it indicates that Bit 30 of any one of the total reactive energy

registers (AVARHR, BVARHR, or CVARHR) has changed. This bit is always 0 for ADE7854.

Rev. H | Page 85 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Bit

Location Bit Mnemonic Default Value

Description

3

FREHF

0

When this bit is set to 1, it indicates that Bit 30 of any one of the fundamental reactive

energy registers, AFVARHR, BFVARHR, or CFVARHR, has changed. This bit is always 0 for

ADE7854, ADE7858, and ADE7868.

4

5

6

VAEHF

0

When this bit is set to 1, it indicates that Bit 30 of any one of the apparent energy

registers (AVAHR, BVAHR, or CVAHR) has changed.

LENERGY

REVAPA

When this bit is set to 1, in line energy accumulation mode, it indicates the end of an

integration over an integer number of half line cycles set in the LINECYC register.

When this bit is set to 1, it indicates that the Phase A active power identified by Bit 6

(REVAPSEL) in the ACCMODE register (total or fundamental) has changed sign. The sign

itself is indicated in Bit 0 (AWSIGN) of the PHSIGN register (see Table 47).

7

REVAPB

0

When this bit is set to 1, it indicates that the Phase B active power identified by Bit 6

(REVAPSEL) in the ACCMODE register (total or fundamental) has changed sign. The sign

itself is indicated in Bit 1 (BWSIGN) of the PHSIGN register (see Table 47).

8

REVAPC

REVPSUM1

REVRPA

When this bit is set to 1, it indicates that the Phase C active power identified by Bit 6

(REVAPSEL) in the ACCMODE register (total or fundamental) has changed sign. The sign

itself is indicated in Bit 2 (CWSIGN) of the PHSIGN register (see Table 47).

9

When this bit is set to 1, it indicates that the sum of all phase powers in the CF1 datapath

has changed sign. The sign itself is indicated in Bit 3 (SUM1SIGN) of the PHSIGN register

(see Table 47).

10

When this bit is set to 1, it indicates that the Phase A reactive power identified by Bit 7

(REVRPSEL) in the ACCMODE register (total or fundamental) has changed sign. The sign

itself is indicated in Bit 4 (AVARSIGN) of the PHSIGN register (see Table 47). This bit is

always 0 for ADE7854.

11

12

REVRPB

REVRPC

0

When this bit is set to 1, it indicates that the Phase B reactive power identified by Bit 7

(REVRPSEL) in the ACCMODE register (total or fundamental) has changed sign. The sign

itself is indicated in Bit 5 (BVARSIGN) of the PHSIGN register (see Table 47). This bit is

always 0 for ADE7854.

When this bit is set to 1, it indicates that the Phase C reactive power identified by Bit 7

(REVRPSEL) in the ACCMODE register (total or fundamental) has changed sign. The sign

itself is indicated in Bit 6 (CVARSIGN) of the PHSIGN register (see Table 47). This bit is

always 0 for ADE7854.

13

14

REVPSUM2

CF1

When this bit is set to 1, it indicates that the sum of all phase powers in the CF2 datapath

has changed sign. The sign itself is indicated in Bit 7 (SUM2SIGN) of the PHSIGN register

(see Table 47).

When this bit is set to 1, it indicates a high to low transition has occurred at CF1 pin; that

is, an active low pulse has been generated. The bit is set even if the CF1 output is disabled

by setting Bit 9 (CF1DIS) to 1 in the CFMODE register. The type of power used at the CF1

pin is determined by Bits[2:0] (CF1SEL[2:0]) in the CFMODE register (see Table 45).

15

16

CF2

CF3

When this bit is set to 1, it indicates a high-to-low transition has occurred at the CF2 pin;

that is, an active low pulse has been generated. The bit is set even if the CF2 output is

disabled by setting Bit 10 (CF2DIS) to 1 in the CFMODE register. The type of power used at

the CF2 pin is determined by Bits[5:3] (CF2SEL[2:0]) in the CFMODE register (see Table 45).

When this bit is set to 1, it indicates a high-to-low transition has occurred at CF3 pin; that

is, an active low pulse has been generated. The bit is set even if the CF3 output is disabled

by setting Bit 11 (CF3DIS) to 1 in the CFMODE register. The type of power used at the CF3

pin is determined by Bits[8:6] (CF3SEL[2:0]) in the CFMODE register (see Table 45).

17

18

DREADY

0

When this bit is set to 1, it indicates that all periodical (at 8 kHz rate) DSP computations

have finished.

REVPSUM3

When this bit is set to 1, it indicates that the sum of all phase powers in the CF3 datapath

has changed sign. The sign itself is indicated in Bit 8 (SUM3SIGN) of the PHSIGN register

(see Table 47).

31:19

Reserved

0 0000 0000 0000 Reserved. These bits are always 0.

Rev. H| Page 86 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Table 38. STATUS1 Register (Address 0xE503)

Bit

Location Bit Mnemonic Default Value Description

0

NLOAD

0

When this bit is set to 1, it indicates that at least one phase entered no load condition based

on total active and reactive powers. The phase is indicated in Bits[2:0] (NLPHASE[x]) in the

PHNOLOAD register (see Table 42).

1

FNLOAD

0

When this bit is set to 1, it indicates that at least one phase entered no load condition based

on fundamental active and reactive powers. The phase is indicated in Bits[5:3] (FNLPHASE[x])

in PHNOLOAD register (see Table 42 in which this register is described). This bit is always 0

for ADE7854, ADE7858, and ADE7868.

2

VANLOAD

0

When this bit is set to 1, it indicates that at least one phase entered no load condition based

on apparent power. The phase is indicated in Bits[8:6] (VANLPHASE[x]) in the PHNOLOAD

register (see Table 42).

3

ZXTOVA

ZXTOVB

ZXTOVC

ZXTOIA

ZXTOIB

ZXTOIC

ZXVA

0

1

When this bit is set to 1, it indicates a zero crossing on Phase A voltage is missing.

When this bit is set to 1, it indicates a zero crossing on Phase B voltage is missing.

When this bit is set to 1, it indicates a zero crossing on Phase C voltage is missing.

When this bit is set to 1, it indicates a zero crossing on Phase A current is missing.

When this bit is set to 1, it indicates a zero crossing on Phase B current is missing.

When this bit is set to 1, it indicates a zero crossing on Phase C current is missing.

When this bit is set to 1, it indicates a zero crossing has been detected on Phase A voltage.

When this bit is set to 1, it indicates a zero crossing has been detected on Phase B voltage.

When this bit is set to 1, it indicates a zero crossing has been detected on Phase C voltage.

When this bit is set to 1, it indicates a zero crossing has been detected on Phase A current.

When this bit is set to 1, it indicates a zero crossing has been detected on Phase B current.

When this bit is set to 1, it indicates a zero crossing has been detected on Phase C current.

4

5

6

7

8

9

10

11

12

13

14

15

ZXVB

ZXVC

ZXIA

ZXIB

ZXIC

RSTDONE

In case of a software reset command, Bit 7 (SWRST) is set to 1 in the CONFIG register, or a

transition from PSM1, PSM2, or PSM3 to PSM0, or a hardware reset, this bit is set to 1 at the

end of the transition process and after all registers changed value to default. The IRQ1 pin

goes low to signal this moment because this interrupt cannot be disabled.

16

17

18

19

SAG

OI

0

When this bit is set to 1, it indicates a SAG event has occurred on one of the phases indicated

by Bits[14:12] (VSPHASE[x]) in the PHSTATUS register (see Table 41).

When this bit is set to 1, it indicates an overcurrent event has occurred on one of the phases

indicated by Bits[5:3] (OIPHASE[x]) in the PHSTATUS register (see Table 41).

OV

When this bit is set to 1, it indicates an overvoltage event has occurred on one of the phases

indicated by Bits[11:9] (OVPHASE[x]) in the PHSTATUS register (see Table 41).

SEQERR

When this bit is set to 1, it indicates a negative-to-positive zero crossing on Phase A voltage

was not followed by a negative-to-positive zero crossing on Phase B voltage but by a

negative-to-positive zero crossing on Phase C voltage.

20

MISMTCH

0

When this bit is set to 1, it indicates ISUM − INWV > ISUMLVL , where ISUMLVL is

indicated in the ISUMLVL register. This bit is always 0 for ADE7854 and ADE7858.

Reserved. This bit is always set to 1.

21

22

23

Reserved

PKI

1

0

Reserved. This bit is always set to 0.

When this bit is set to 1, it indicates that the period used to detect the peak value in the

current channel has ended. The IPEAK register contains the peak value and the phase where

the peak has been detected (see Table 35).

24

PKV

0

When this bit is set to 1, it indicates that the period used to detect the peak value in the

voltage channel has ended. VPEAK register contains the peak value and the phase where the

peak has been detected (see Table 36).

31:25

Reserved

000 0000

Reserved. These bits are always 0.

Rev. H| Page 87 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Table 39. MASK0 Register (Address 0xE50A)

Bit

Location Bit Mnemonic Default Value Description

0

1

AEHF

0

When this bit is set to 1, it enables an interrupt when Bit 30 of any one of the total active

energy registers (AWATTHR, BWATTHR, or CWATTHR) changes.

FAEHF

0

When this bit is set to 1, it enables an interrupt when Bit 30 of any one of the fundamental

active energy registers (AFWATTHR, BFWATTHR, or CFWATTHR) changes. Setting this bit to1

does not have any consequence for ADE7854, ADE7858, and ADE7868.

2

3

REHF

0

When this bit is set to 1, it enables an interrupt when Bit 30 of any one of the total reactive

energy registers (AVARHR, BVARHR, CVARHR) changes. Setting this bit to1 does not have any

consequence for ADE7854.

FREHF

When this bit is set to 1, it enables an interrupt when Bit 30 of any one of the fundamental

reactive energy registers (AFVARHR, BFVARHR, or CFVARHR) changes. Setting this bit to1

does not have any consequence for ADE7854, ADE7858, and ADE7868.

4

VAEHF

0

When this bit is set to 1, it enables an interrupt when Bit 30 of any one of the apparent

energy registers (AVAHR, BVAHR, or CVAHR) changes.

5

LENERGY

REVAPA

REVAPB

REVAPC

REVPSUM1

REVRPA

When this bit is set to 1, in line energy accumulation mode, it enables an interrupt at the end

of an integration over an integer number of half line cycles set in the LINECYC register.

6

When this bit is set to 1, it enables an interrupt when the Phase A active power identified by

Bit 6 (REVAPSEL) in the ACCMODE register (total or fundamental) changes sign.

7

When this bit is set to 1, it enables an interrupt when the Phase B active power identified by

Bit 6 (REVAPSEL) in the ACCMODE register (total or fundamental) changes sign.

8

When this bit is set to 1, it enables an interrupt when the Phase C active power identified by

Bit 6 (REVAPSEL) in the ACCMODE register (total or fundamental) changes sign.

9

When this bit is set to 1, it enables an interrupt when the sum of all phase powers in the CF1

datapath changes sign.

10

When this bit is set to 1, it enables an interrupt when the Phase A reactive power identified

by Bit 7 (REVRPSEL) in the ACCMODE register (total or fundamental) changes sign. Setting

this bit to1 does not have any consequence for ADE7854.

11

12

REVRPB

REVRPC

0

When this bit is set to 1, it enables an interrupt when the Phase B reactive power identified

by Bit 7 (REVRPSEL) in the ACCMODE register (total or fundamental) changes sign. Setting

this bit to1 does not have any consequence for ADE7854.

When this bit is set to 1, it enables an interrupt when the Phase C reactive power identified

by Bit 7 (REVRPSEL) in the ACCMODE register (total or fundamental) changes sign. Setting

this bit to1 does not have any consequence for ADE7854.

13

14

REVPSUM2

CF1

When this bit is set to 1, it enables an interrupt when the sum of all phase powers in the CF2

datapath changes sign.

When this bit is set to 1, it enables an interrupt when a high-to-low transition occurs at the

CF1 pin, that is, an active low pulse is generated. The interrupt can be enabled even if the

CF1 output is disabled by setting Bit 9 (CF1DIS) to 1 in the CFMODE register. The type of

power used at the CF1 pin is determined by Bits[2:0] (CF1SEL[2:0]) in the CFMODE register

(see Table 45).

15

16

CF2

CF3

When this bit is set to 1, it enables an interrupt when a high-to-low transition occurs at CF2

pin, that is, an active low pulse is generated. The interrupt may be enabled even if the CF2

output is disabled by setting Bit 10 (CF2DIS) to 1 in the CFMODE register. The type of power

used at the CF2 pin is determined by Bits[5:3] (CF2SEL[2:0]) in the CFMODE register (see Table 45).

When this bit is set to 1, it enables an interrupt when a high to low transition occurs at CF3

pin, that is, an active low pulse is generated. The interrupt may be enabled even if the CF3

output is disabled by setting Bit 11 (CF3DIS) to 1 in the CFMODE register. The type of power

used at the CF3 pin is determined by Bits[8:6] (CF3SEL[2:0]) in the CFMODE register (see Table 45).

17

DREADY

0

When this bit is set to 1, it enables an interrupt when all periodical (at 8 kHz rate) DSP

computations finish.

18

REVPSUM3

Reserved

When this bit is set to 1, it enables an interrupt when the sum of all phase powers in the CF3

datapath changes sign.

31:19

00 0000 0000

0000

Reserved. These bits do not manage any functionality.

Rev. H| Page 88 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Table 40. MASK1 Register (Address 0xE50B)

Bit

Location Bit Mnemonic Default Value Description

0

1

NLOAD

0

When this bit is set to 1, it enables an interrupt when at least one phase enters no load

condition based on total active and reactive powers.

FNLOAD

0

When this bit is set to 1, it enables an interrupt when at least one phase enters no load

condition based on fundamental active and reactive powers. Setting this bit to 1 does not

have any consequence for ADE7854, ADE7858, and ADE7868.

2

VANLOAD

ZXTOVA

ZXTOVB

ZXTOVC

ZXTOIA

ZXTOIB

ZXTOIC

ZXVA

0

When this bit is set to 1, it enables an interrupt when at least one phase enters no load

condition based on apparent power.

3

When this bit is set to 1, it enables an interrupt when a zero crossing on Phase A voltage is

missing.

4

When this bit is set to 1, it enables an interrupt when a zero crossing on Phase B voltage is

missing.

5

When this bit is set to 1, it enables an interrupt when a zero crossing on Phase C voltage is

missing.

6

When this bit is set to 1, it enables an interrupt when a zero crossing on Phase A current is

missing.

7

When this bit is set to 1, it enables an interrupt when a zero crossing on Phase B current is

missing.

8

When this bit is set to 1, it enables an interrupt when a zero crossing on Phase C current is

missing.

9

When this bit is set to 1, it enables an interrupt when a zero crossing is detected on Phase A

voltage.

10

11

12

13

14

15

16

17

18

19

ZXVB

When this bit is set to 1, it enables an interrupt when a zero crossing is detected on Phase B

voltage.

ZXVC

When this bit is set to 1, it enables an interrupt when a zero crossing is detected on Phase C

voltage.

ZXIA

When this bit is set to 1, it enables an interrupt when a zero crossing is detected on Phase A

current.

ZXIB

When this bit is set to 1, it enables an interrupt when a zero crossing is detected on Phase B

current.

ZXIC

When this bit is set to 1, it enables an interrupt when a zero crossing is detected on Phase C

current.

RSTDONE

SAG

Because the RSTDONE interrupt cannot be disabled, this bit does not have any functionality

attached. It can be set to 1 or cleared to 0 without having any effect.

When this bit is set to 1, it enables an interrupt when a SAG event occurs on one of the

phases indicated by Bits[14:12] (VSPHASE[x]) in the PHSTATUS register (see Table 41).

OI

When this bit is set to 1, it enables an interrupt when an overcurrent event occurs on one of

the phases indicated by Bits[5:3] (OIPHASE[x]) in the PHSTATUS register (see Table 41).

OV

When this bit is set to 1, it enables an interrupt when an overvoltage event occurs on one of

the phases indicated by Bits[11:9] (OVPHASE[x]) in the PHSTATUS register (see Table 41).

SEQERR

When this bit is set to 1, it enables an interrupt when a negative-to-positive zero crossing on

Phase A voltage is not followed by a negative-to-positive zero crossing on Phase B voltage,

but by a negative-to-positive zero crossing on Phase C voltage.

20

MISMTCH

0

When this bit is set to 1, it enables an interrupt when ISUM − INWV > ISUMLVL is

greater than the value indicated in ISUMLVL register. Setting this bit to1 does not have any

consequence for ADE7854 and ADE7858.

22:21

23

Reserved

PKI

00

0

Reserved. These bits do not manage any functionality.

When this bit is set to 1, it enables an interrupt when the period used to detect the peak

value in the current channel has ended.

24

PKV

0

When this bit is set to 1, it enables an interrupt when the period used to detect the peak

value in the voltage channel has ended.

31:25

Reserved

000 0000

Reserved. These bits do not manage any functionality.

Rev. H| Page 89 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Table 41. PHSTATUS Register (Address 0xE600)

Bit

Location Bit Mnemonic Default Value Description

2:0

3

Reserved

000

0

Reserved. These bits are always 0.

OIPHASE[0]

OIPHASE[1]

OIPHASE[2]

Reserved

When this bit is set to 1, Phase A current generates Bit 17 (OI) in the STATUS1 register.

When this bit is set to 1, Phase B current generates Bit 17 (OI) in the STATUS1 register.

When this bit is set to 1, Phase C current generates Bit 17 (OI) in the STATUS1 register.

Reserved. These bits are always 0.

4

0

5

0

8:6

9

000

0

OVPHASE[0]

OVPHASE[1]

OVPHASE[2]

VSPHASE[0]

VSPHASE[1]

VSPHASE[2]

Reserved

When this bit is set to 1, Phase A voltage generates Bit 18 (OV) in the STATUS1 register.

When this bit is set to 1, Phase B voltage generates Bit 18 (OV) in the STATUS1 register.

When this bit is set to 1, Phase C voltage generates Bit 18 (OV) in the STATUS1 register.

When this bit is set to 1, Phase A voltage generates Bit 16 (SAG) in the STATUS1 register.

When this bit is set to 1, Phase B voltage generates Bit 16 (SAG) in the STATUS1 register.

When this bit is set to 1, Phase C voltage generates Bit16 (SAG) in the STATUS1 register.

Reserved. This bit is always 0.

10

11

12

13

14

15

0

Table 42. PHNOLOAD Register (Address 0xE608)

Bit

Location Bit Mnemonic Default Value Description

0

1

2

NLPHASE[0]

NLPHASE[1]

NLPHASE[2]

0

0: Phase A is out of no load condition based on total active/reactive powers.

1: Phase A is in no load condition based on total active/reactive powers. Bit set together with

Bit 0 (NLOAD) in the STATUS1 register.

The ADE7854 no load condition is based only on the total active powers.

0: Phase B is out of no load condition based on total active/reactive powers.

1: Phase B is in no load condition based on total active/reactive powers. Bit set together with

Bit 0 (NLOAD) in the STATUS1 register.

The ADE7854 no load condition is based only on the total active powers.

0: Phase C is out of no load condition based on total active/reactive powers.

1: Phase C is in no load condition based on total active/reactive powers. Bit set together with

Bit 0 (NLOAD) in the STATUS1 register.

The ADE7854 no load condition is based only on the total active powers.

3

4

5

FNLPHASE[0]

FNLPHASE[1]

FNLPHASE[2]

0

0: Phase A is out of no load condition based on fundamental active/reactive powers. This bit

is always 0 for ADE7854, ADE7858, and ADE7868.

1: Phase A is in no load condition based on fundamental active/reactive powers. This bit is

set together with Bit 1 (FNLOAD) in STATUS1.

0: Phase B is out of no load condition based on fundamental active/reactive powers. This bit

is always 0 for ADE7854, ADE7858, and ADE7868.

1: Phase B is in no load condition based on fundamental active/reactive powers. This bit is

set together with Bit 1 (FNLOAD) in STATUS1.

0: Phase C is out of no load condition based on fundamental active/reactive powers. This bit

is always 0 for ADE7854, ADE7858, and ADE7868.

1: Phase C is in no load condition based on fundamental active/reactive powers. This bit is

set together with Bit 1 (FNLOAD) in STATUS1.

6

VANLPHASE[0]

VANLPHASE[1]

VANLPHASE[2]

Reserved

0

0: Phase A is out of no load condition based on apparent power.

1: Phase A is in no load condition based on apparent power. Bit set together with Bit 2

(VANLOAD) in the STATUS1 register.

7

0

0: Phase B is out of no load condition based on apparent power.

1: Phase B is in no load condition based on apparent power. Bit set together with Bit 2

(VANLOAD) in the STATUS1 register.

8

0

0: Phase C is out of no load condition based on apparent power.

1: Phase C is in no load condition based on apparent power. Bit set together with Bit 2

(VANLOAD) in the STATUS1 register.

15:9

000 0000

Reserved. These bits are always 0.

Rev. H| Page 90 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Table 43. COMPMODE Register (Address 0xE60E)

Bit

Location Bit Mnemonic Default Value Description

0

TERMSEL1[0]

1

Setting all TERMSEL1[2:0] to 1 signifies the sum of all three phases is included in the CF1

output. Phase A is included in the CF1 outputs calculations.

1

2

3

TERMSEL1[1]

TERMSEL1[2]

TERMSEL2[0]

1

Phase B is included in the CF1 outputs calculations.

Phase C is included in the CF1 outputs calculations.

Setting all TERMSEL2[2:0] to 1 signifies the sum of all three phases is included in the CF2

output. Phase A is included in the CF2 outputs calculations.

4

5

6

TERMSEL2[1]

TERMSEL2[2]

TERMSEL3[0]

1

Phase B is included in the CF2 outputs calculations.

Phase C is included in the CF2 outputs calculations.

Setting all TERMSEL3[2:0] to 1 signifies the sum of all three phases is included in the CF3

output. Phase A is included in the CF3 outputs calculations.

7

TERMSEL3[1]

TERMSEL3[2]

1

Phase B is included in the CF3 outputs calculations.

Phase C is included in the CF3 outputs calculations.

00: the angles between phase voltages and phase currents are measured.

01: the angles between phase voltages are measured.

10: the angles between phase currents are measured.

11: no angles are measured.

8

10:9

ANGLESEL[1:0] 00

11

12

13

VNOMAEN

VNOMBEN

VNOMCEN

0

When this bit is 0, the apparent power on Phase A is computed regularly.

When this bit is 1, the apparent power on Phase A is computed using VNOM register instead

of regular measured rms phase voltage. The applied Phase A voltage input is ignored, and all

Phase A rms voltage instances are replaced by the value in the VNOM register.

When this bit is 0, the apparent power on Phase B is computed regularly.

When this bit is 1, the apparent power on Phase B is computed using VNOM register instead

of regular measured rms phase voltage. The applied Phase B voltage input is ignored, and all

Phase B rms voltage instances are replaced by the value in the VNOM register.

When this bit is 0, the apparent power on Phase C is computed regularly.

When this bit is 1, the apparent power on Phase C is computed using VNOM register instead

of regular measured rms phase voltage. The applied Phase C voltage input is ignored, and all

Phase C rms voltage instances are replaced by the value in the VNOM register.

14

15

SELFREQ

Reserved

0

When the ADE7878 is connected to 50 Hz networks, this bit should be cleared to 0 (default

value). When the ADE7878 is connected to 60 Hz networks, this bit should be set to 1. This

bit does not have any consequence for ADE7854, ADE7858, and ADE7868.

This bit is 0 by default and it does not manage any functionality.

Table 44. Gain Register (Address 0xE60F)

Bit

Location Bit Mnemonic

Default Value

000

Description

2:0

PGA1[2:0]

Phase currents gain selection.

000: gain = 1.

001: gain = 2.

010: gain = 4.

011: gain = 8.

100: gain = 16.

101, 110, 111: reserved. When set, the ADE7854/ADE7858/ADE7868/ADE7878 behave

like PGA1[2:0] = 000.

5:3

PGA2[2:0]

000

Neutral current gain selection.

000: gain = 1. These bits are always 000 for ADE7854 and ADE7858.

001: gain = 2.

010: gain = 4.

011: gain = 8.

100: gain = 16.

101, 110, 111: reserved. When set, the ADE7868/ADE7878 behave like PGA2[2:0] =

000.

Rev. H| Page 91 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

8:6

PGA3[2:0]

000

Phase voltages gain selection.

000: gain = 1.

001: gain = 2.

010: gain = 4.

011: gain = 8.

100: gain = 16.

101, 110, 111: reserved. When set, the ADE7854/ADE7858/ADE7868/ADE7878 behave

like PGA3[2:0] = 000.

15:9

Reserved

000 0000

Reserved. These bits do not manage any functionality.

Table 45. CFMODE Register (Address 0xE610)

Bit

Location Bit Mnemonic Default Value Description

2:0

5:3

8:6

9

CF1SEL[2:0]

CF2SEL[2:0]

CF3SEL[2:0]

CF1DIS

000

001

010

1

000: the CF1 frequency is proportional to the sum of total active powers on each phase

identified by Bits[2:0] (TERMSEL1[x]) in the COMPMODE register.

001: the CF1 frequency is proportional to the sum of total reactive powers on each phase

identified by Bits[2:0] (TERMSEL1[x]) in the COMPMODE register. This condition does not

have any consequence for the ADE7854.

010: the CF1 frequency is proportional to the sum of apparent powers on each phase

identified by Bits[2:0] (TERMSEL1[x]) in the COMPMODE register.

011: the CF1 frequency is proportional to the sum of fundamental active powers on each

phase identified by Bits[2:0] (TERMSEL1[x]) in the COMPMODE register. This condition does

not have any consequence for the ADE7854, ADE7858, and ADE7868.

100: the CF1 frequency is proportional to the sum of fundamental reactive powers on each

phase identified by Bits[2:0] (TERMSEL1[x]) in the COMPMODE register. This condition does

not have any consequence for the ADE7854, ADE7858, and ADE7868.

101, 110, 111: reserved. When set, the CF1 signal is not generated.

000: the CF2 frequency is proportional to the sum of total active powers on each phase

identified by Bits[5:3] (TERMSEL2[x]) in the COMPMODE register.

001: the CF2 frequency is proportional to the sum of total reactive powers on each phase

identified by Bits[5:3] (TERMSEL2[x]) in the COMPMODE register. This condition does not

have any consequence for the ADE7854.

010: the CF2 frequency is proportional to the sum of apparent powers on each phase

identified by Bits[5:3] (TERMSEL2[x]) in the COMPMODE register.

011: the CF2 frequency is proportional to the sum of fundamental active powers on each

phase identified by Bits[5:3] (TERMSEL2[x]) in the COMPMODE register. This condition does

not have any consequence for the ADE7854, ADE7858, and ADE7868.

100: the CF2 frequency is proportional to the sum of fundamental reactive powers on each

phase identified by Bits[5:3] (TERMSEL2[x]) in the COMPMODE register. This condition does

not have any consequence for the ADE7854, ADE7858, and ADE7868.

101,110,111: reserved. When set, the CF2 signal is not generated.

000: the CF3 frequency is proportional to the sum of total active powers on each phase

identified by Bits[8:6] (TERMSEL3[x]) in the COMPMODE register.

001: the CF3 frequency is proportional to the sum of total reactive powers on each phase

identified by Bits[8:6] (TERMSEL3[x]) in the COMPMODE register. This condition does not

have any consequence for the ADE7854.

010: the CF3 frequency is proportional to the sum of apparent powers on each phase

identified by Bits[8:6] (TERMSEL3[x]) in the COMPMODE register.

011: CF3 frequency is proportional to the sum of fundamental active powers on each phase

identified by Bits[8:6] (TERMSEL3[x]) in the COMPMODE register. This condition does not

have any consequence for the ADE7854, ADE7858, and ADE7868.

100: CF3 frequency is proportional to the sum of fundamental reactive powers on each

phase identified by Bits[8:6] (TERMSEL3[x]) in the COMPMODE register. This condition does

not have any consequence for the ADE7854, ADE7858, and ADE7868.

101,110,111: reserved. When set, the CF3 signal is not generated.

When this bit is set to 1, the CF1 output is disabled. The respective digital to frequency

converter remains enabled even if CF1DIS = 1.

When this bit is set to 0, the CF1 output is enabled.

Rev. H| Page 92 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Bit

Location Bit Mnemonic Default Value Description

10

CF2DIS

1

When this bit is set to 1, the CF2 output is disabled. The respective digital to frequency

converter remains enabled even if CF2DIS = 1.

When this bit is set to 0, the CF2 output is enabled.

11

CF3DIS

1

When this bit is set to 1, the CF3 output is disabled. The respective digital to frequency

converter remains enabled even if CF3DIS = 1.

When this bit is set to 0, the CF3 output is enabled.

12

13

14

15

CF1LATCH

CF2LATCH

CF3LATCH

Reserved

0

When this bit is set to 1, the content of the corresponding energy registers is latched when a

CF1 pulse is generated. See the Synchronizing Energy Registers with CFx Outputs section.

When this bit is set to 1, the content of the corresponding energy registers is latched when a

CF2 pulse is generated. See the Synchronizing Energy Registers with CFx Outputs section.

When this bit is set to 1, the content of the corresponding energy registers is latched when a

CF3 pulse is generated. See the Synchronizing Energy Registers with CFx Outputs section.

Reserved. This bit does not manage any functionality.

Table 46. APHCAL, BPHCAL, CPHCAL Registers (Address 0xE614, Address 0xE615, Address 0xE616)

Bit

Location Bit Mnemonic Default Value Description

9:0

PHCALVAL

0000000000

If the current leads the voltage, these bits can vary only between 0 and 383.

If the current lags the voltage, these bits can vary only between 512 and 575.

If the PHCALVAL bits are set with numbers between 384 and 511, the compensation behaves

like PHCALVAL set between 256 and 383.

If the PHCALVAL bits are set with numbers between 576 and 1023, the compensation

behaves like PHCALVAL bits set between 384 and 511.

15:10

Reserved

000000

Reserved. These bits do not manage any functionality.

Table 47. PHSIGN Register (Address 0xE617)

Bit

Location Bit Mnemonic Default Value Description

0

1

2

3

4

5

6

AWSIGN

0

0: if the active power identified by Bit 6 (REVAPSEL) in the ACCMODE register (total of

fundamental) on Phase A is positive.

1: if the active power identified by Bit 6 (REVAPSEL) in the ACCMODE register (total of

fundamental) on Phase A is negative.

BWSIGN

0: if the active power identified by Bit 6 (REVAPSEL) in the ACCMODE register (total of

fundamental) on Phase B is positive.

1: if the active power identified by Bit 6 (REVAPSEL) in the ACCMODE register (total of

fundamental) on Phase B is negative.

CWSIGN

0: if the active power identified by Bit 6 (REVAPSEL) in the ACCMODE register (total of

fundamental) on Phase C is positive.

1: if the active power identified by Bit 6 (REVAPSEL) bit in the ACCMODE register (total of

fundamental) on Phase C is negative.

SUM1SIGN

AVARSIGN

BVARSIGN

CVARSIGN

0: if the sum of all phase powers in the CF1 datapath is positive.

1: if the sum of all phase powers in the CF1 datapath is negative. Phase powers in the CF1

datapath are identified by Bits[2:0] (TERMSEL1[x]) of the COMPMODE register and by

Bits[2:0] (CF1SEL[x]) of the CFMODE register.

0: if the reactive power identified by Bit 7 (REVRPSEL) in the ACCMODE register (total of

fundamental) on Phase A is positive. This bit is always 0 for ADE7854.

1: if the reactive power identified by Bit 7 (REVRPSEL) in the ACCMODE register (total of

fundamental) on Phase A is negative.

0: if the reactive power identified by Bit 7 (REVRPSEL) in the ACCMODE register (total of

fundamental) on Phase B is positive. This bit is always 0 for ADE7854.

1: if the reactive power identified by Bit 7 (REVRPSEL) in the ACCMODE register (total of

fundamental) on Phase B is negative.

0: if the reactive power identified by Bit 7 (REVRPSEL) in the ACCMODE register (total of

fundamental) on Phase C is positive. This bit is always 0 for ADE7854.

1: if the reactive power identified by Bit 7 (REVRPSEL) in the ACCMODE register (total of

fundamental) on Phase C is negative.

Rev. H| Page 93 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Bit

Location Bit Mnemonic Default Value Description

7

SUM2SIGN

SUM3SIGN

Reserved

0

0: if the sum of all phase powers in the CF2 datapath is positive.

1: if the sum of all phase powers in the CF2 datapath is negative. Phase powers in the CF2

datapath are identified by Bits[5:3] (TERMSEL2[x]) of the COMPMODE register and by

Bits[5:3] (CF2SEL[x]) of the CFMODE register.

8

0

0: if the sum of all phase powers in the CF3 datapath is positive.

1: if the sum of all phase powers in the CF3 datapath is negative. Phase powers in the CF3

datapath are identified by Bits[8:6] (TERMSEL3[x]) of the COMPMODE register and by

Bits[8:6] (CF3SEL[x]) of the CFMODE register.

15:9

000 0000

Reserved. These bits are always 0.

Table 48. CONFIG Register (Address 0xE618)

Bit

Location Bit Mnemonic Default Value Description

0

INTEN

0

Integrator enable. When this bit is set to 1, the internal digital integrator is enabled for use in

meters utilizing Rogowski coils on all 3-phase and neutral current inputs.

When this bit is cleared to 0, the internal digital integrator is disabled.

Reserved. These bits do not manage any functionality.

2:1

3

Reserved

SWAP

00

0

When this bit is set to 1, the voltage channel outputs are swapped with the current channel

outputs. Thus, the current channel information is present in the voltage channel registers

and vice versa.

4

5

6

MOD1SHORT

MOD2SHORT

HSDCEN

0

When this bit is set to 1, the voltage channel ADCs behave as if the voltage inputs were put

to ground.

When this bit is set to 1, the current channel ADCs behave as if the voltage inputs were put

to ground.

When this bit is set to 1, the HSDC serial port is enabled and HSCLK functionality is chosen at

CF3/HSCLK pin.

When this bit is cleared to 0, HSDC is disabled and CF3 functionality is chosen at CF3/HSCLK pin.

When this bit is set to 1, a software reset is initiated.

7

SWRST

0

9:8

VTOIA[1:0]

00

These bits decide what phase voltage is considered together with Phase A current in the

power path.

00 = Phase A voltage.

01 = Phase B voltage.

10 = Phase C voltage.

11 = reserved. When set, the ADE7854/ADE7858/ADE7868/ADE7878 behave like VTOIA[1:0] =

00.

11:10

13:12

15:14

VTOIB[1:0]

VTOIC[1:0]

Reserved

00

0

These bits decide what phase voltage is considered together with Phase B current in the

power path.

00 = Phase B voltage.

01 = Phase C voltage.

10 = Phase A voltage.

11 = reserved. When set, the ADE7854/ADE7858/ADE7868/ADE7878 behave like VTOIB[1:0] =

00.

These bits decide what phase voltage is considered together with Phase C current in the

power path.

00 = Phase C voltage.

01 = Phase A voltage.

10 = Phase B voltage.

11 = reserved. When set, the ADE7854/ADE7858/ADE7868/ADE7878 behave like VTOIC[1:0] =

00.

Reserved. These bits do not manage any functionality.

Rev. H| Page 94 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Table 49. MMODE Register (Address 0xE700)

Bit

Location Bit Mnemonic Default Value Description

1:0

PERSEL[1:0]

PEAKSEL[0]

00

00: Phase A selected as the source of the voltage line period measurement.

01: Phase B selected as the source of the voltage line period measurement.

10: Phase C selected as the source of the voltage line period measurement.

11: reserved. When set, the ADE7854/ADE7858/ADE7868/ADE7878 behave like PERSEL[1:0] = 00.

2

1

PEAKSEL[2:0] bits can all be set to 1 simultaneously to allow peak detection on all three

phases simultaneously. If more than one PEAKSEL[2:0] bits are set to 1, then the peak

measurement period indicated in the PEAKCYC register decreases accordingly because zero

crossings are detected on more than one phase.

When this bit is set to 1, Phase A is selected for the voltage and current peak registers.

When this bit is set to 1, Phase B is selected for the voltage and current peak registers.

When this bit is set to 1, Phase C is selected for the voltage and current peak registers.

Reserved. These bits do not manage any functionality.

3

PEAKSEL[1]

PEAKSEL[2]

Reserved

1

4

1

7:5

000

Table 50. ACCMODE Register (Address 0xE701)

Bit

Location Bit Mnemonic Default Value Description

1:0

WATTACC[1:0]

00

00: signed accumulation mode of the total and fundamental active powers. Fundamental

active powers are available in the ADE7878.

01: reserved. When set, the device behaves like WATTACC[1:0] = 00.

10: reserved. When set, the device behaves like WATTACC[1:0] = 00.

11: absolute accumulation mode of the total and fundamental active powers.

3:2

VARACC[1:0]

00

00: signed accumulation of the total and fundamental reactive powers. Total reactive powers

are available in the ADE7858, ADE7868, and ADE7878. Fundamental reactive powers are

available in the ADE7878. These bits are always 00 for the ADE7854.

01: reserved. When set, the device behaves like VARACC[1:0] = 00.

10: the total and fundamental reactive powers are accumulated, depending on the sign of

the total and fundamental active power: if the active power is positive, the reactive power is

accumulated as is, whereas if the active power is negative, the reactive power is accumulated

with reversed sign.

11: reserved. When set, the device behave like VARACC[1:0] = 00.

5:4

CONSEL[1:0]

00

These bits select the inputs to the energy accumulation registers. IA’, IB’, and IC’ are IA, IB, and

IC shifted respectively by −90°. See Table 51.

00: 3-phase four wires with three voltage sensors.

01: 3-phase three wires delta connection.

10: 3-phase four wires with two voltage sensors.

11: 3-phase four wires delta connection.

6

7

REVAPSEL

REVRPSEL

0

0: The total active power on each phase is used to trigger a bit in the STATUS0 register as

follows: on Phase A triggers Bit 6 (REVAPA), on Phase B triggers Bit 7 (REVAPB), and on

Phase C triggers Bit 8 (REVAPC). This bit is always 0 for the ADE7854, ADE7858, and ADE7868.

1: The fundamental active power on each phase is used to trigger a bit in the STATUS0

register as follows: on Phase A triggers Bit 6 (REVAPA), on Phase B triggers Bit 7 (REVAPB),

and on Phase C triggers Bit 8 (REVAPC).

0: The total reactive power on each phase is used to trigger a bit in the STATUS0 register as

follows: on Phase A triggers Bit 10 (REVRPA), on Phase B triggers Bit 11 (REVRPB), and on

Phase C triggers Bit 12 (REVRPC). This bit is always 0 for the ADE7854, ADE7858, and

ADE7868.

1: The fundamental reactive power on each phase is used to trigger a bit in the STATUS0

register as follows: on Phase A triggers Bit 10 (REVRPA), on Phase B triggers Bit 11 (REVRPB),

and on Phase C triggers Bit 12 (REVRPC).

Rev. H| Page 95 of 100

ADE7854/ADE7858/ADE7868/ADE7878

Data Sheet

Table 51. CONSEL[1:0] Bits in Energy Registers

Energy Registers

CONSEL[1:0] = 00

CONSEL[1:0] = 01

CONSEL[1:0] = 10

VA × IA

VB = −VA − VC

VB × IB

CONSEL[1:0] = 11

AWATTHR, AFWATTHR

BWATTHR, BFWATTHR

VA × IA

VB × IB

VA × IA

0

VA × IA

VB = −VA

VB × IB

CWATTHR, CFWATTHR

AVARHR, AFVARHR

BVARHR, BFVARHR

VC × IC

VA × IA’

VB × IB’

VC × IC

VA × IA’

0

VC × IC

VA × IA’

VB = −VA − VC

VB × IB’

VC × IC

VA × IA’

VB = −VA

VB × IB’

CVARHR, CFVARHR

AVAHR

BVAHR

VC × IC’

VA rms × IA rms

0

VC × IC’

VA rms × IA rms

VB rms × IB rms

VC rms × IC rms

VA rms × IA rms

VB rms × IB rms

VC rms × IC rms

VA rms × IA rms

VB rms × IB rms

VC rms × IC rms

CVAHR

VC rms × IC rms

Table 52. LCYCMODE Register (Address 0xE702)

Bit

Location Bit Mnemonic Default Value Description

0

1

2

3

LWATT

0

1

0: the watt-hour accumulation registers (AWATTHR, BWATTHR, CWATTHR, AFWATTHR,

BFWATTHR, and CFWATTHR) are placed in regular accumulation mode.

1: the watt-hour accumulation registers (AWATTHR, BWATTHR, CWATTHR, AFWATTHR,

BFWATTHR, and CFWATTHR) are placed into line cycle accumulation mode.

LVAR

0: the var-hour accumulation registers (AVARHR, BVARHR, and CVARHR) are placed in regular

accumulation mode. This bit is always 0 for the ADE7854.

1: the var-hour accumulation registers (AVARHR, BVARHR, and CVARHR) are placed into line-

cycle accumulation mode.

LVA

0: the VA-hour accumulation registers (AVAHR, BVAHR, and CVAHR) are placed in regular

accumulation mode.

1: the VA-hour accumulation registers (AVAHR, BVAHR, and CVAHR) are placed into line-cycle

accumulation mode.

ZXSEL[0]

0: Phase A is not selected for zero-crossings counts in the line cycle accumulation mode.

1: Phase A is selected for zero-crossings counts in the line cycle accumulation mode. If more

than one phase is selected for zero-crossing detection, the accumulation time is shortened

accordingly.

4

5

6

ZXSEL[1]

ZXSEL[2]

RSTREAD

1

0: Phase B is not selected for zero-crossings counts in the line cycle accumulation mode.

1: Phase B is selected for zero-crossings counts in the line cycle accumulation mode.

0: Phase C is not selected for zero-crossings counts in the line cycle accumulation mode.

1: Phase C is selected for zero-crossings counts in the line cycle accumulation mode.

0: read-with-reset of all energy registers is disabled. Clear this bit to 0 when Bits[2:0] (LWATT,

LVAR, and LVA) are set to 1.

1: enables read-with-reset of all xWATTHR, xVARHR, xVAHR, xFWATTHR, and xFVARHR

registers. This means a read of those registers resets them to 0.

7

Reserved

0

Reserved. This bit does not manage any functionality.

Table 53. HSDC_CFG Register (Address 0xE706)

Bit

Location Bit Mnemonic Default Value Description

0

1

2

HCLK

HSIZE

HGAP

0

0: HSCLK is 8 MHz.

1: HSCLK is 4 MHz.

0: HSDC transmits the 32-bit registers in 32-bit packages, most significant bit first.

1: HSDC transmits the 32-bit registers in 8-bit packages, most significant bit first.

0: no gap is introduced between packages.

1: a gap of seven HCLK cycles is introduced between packages.

Rev. H| Page 96 of 100

Data Sheet

ADE7854/ADE7858/ADE7868/ADE7878

Bit

Location Bit Mnemonic Default Value Description

4:3

HXFER[1:0]

00

00 = for ADE7854, HSDC transmits sixteen 32-bit words in the following order: IAWV, VAWV,

IBWV, VBWV, ICWV, and VCWV, one 32-bit word equal to 0, AVA, BVA, CVA, AWATT, BWATT,

and CWATT, three 32-bit words equal to 0. For ADE7858, HSDC transmits sixteen 32-bit

words in the following order: IAWV, VAWV, IBWV, VBWV, ICWV, and VCWV, one 32-bit word

equal to 0, AVA, BVA, CVA, AWATT, BWATT, CWATT, AVAR, BVAR, and CVAR. For the ADE7868

and ADE7878, HSDC transmits sixteen 32-bit words in the following order: IAWV, VAWV, IBWV,

VBWV, ICWV, VCWV, INWV, AVA, BVA, CVA, AWATT, BWATT, CWATT, AVAR, BVAR, and CVAR.

01 = for the ADE7854 and ADE7858, HSDC transmits six instantaneous values of currents

and voltages: IAWV, VAWV, IBWV, VBWV, ICWV, and VCWV, and one 32-bit word equal to 0.

For the ADE7868 and ADE7878, HSDC transmits seven instantaneous values of currents and

voltages: IAWV, VAWV, IBWV, VBWV, ICWV, VCWV, and INWV.

10 = for the ADE7854, HSDC transmits six instantaneous values of phase powers: AVA, BVA,

CVA, AWATT, BWATT, and CWATT and three 32-bit words equal to 0. For the ADE7858,

ADE7868, and ADE7878, HSDC transmits nine instantaneous values of phase powers: AVA,

BVA, CVA, AWATT, BWATT, CWATT, AVAR, BVAR, and CVAR.

11 = reserved. If set, the ADE7854/ADE7858/ADE7868/ADE7878 behave as if HXFER[1:0] = 00.

0: SS/HSA output pin is active low.

5

HSAPOL

0

1: SS/HSA output pin is active high.

7:6

Reserved

00

Reserved. These bits do not manage any functionality.

Table 54. LPOILVL Register (Address 0xEC00)¹

Bit Location

Bit Mnemonic

Default Value

Description

2:0

LPOIL[2:0]

111

Threshold is put at a value corresponding to full scale multiplied by LPOIL/8.

7:3

LPLINE[4:0]

00000

The measurement period is (LPLINE + 1)/50 seconds.

¹The LPOILVL register is available only for the ADE7868 and ADE7878; it is reserved for ADE7854 and ADE7858.

Table 55. CONFIG2 Register (Address 0xEC01)

Bit

Location Bit Mnemonic Default Value Description

0

1

EXTREFEN

0

When this bit is 0, it signifies that the internal voltage reference is used in the ADCs.

When this bit is 1, an external reference is connected to the Pin 17 REF_IN/OUT

.

I2C_LOCK

0

When this bit is 0, the SS/HSA pin can be toggled three times to activate the SPI port. If I²C is

the active serial port, this bit must be set to 1 to lock it in. From this moment on, spurious

toggling of the SS/HSA pin and an eventual switch into using the SPI port is no longer possible. If

SPI is the active serial port, any write to CONFIG2 register locks the port. From this moment

on, a switch into using I²C port is no longer possible. Once locked, the serial port choice is

maintained when the ADE7854/ADE7858/ADE7868/ADE7878 change PSMx power modes.

7:2

Reserved

0

Reserved. These bits do not manage any functionality.

Rev. H| Page 97 of 100

ADE7854/ADE7858/ADE7868/ADE7878

OUTLINE DIMENSIONS

Data Sheet

6.10

6.00 SQ

5.90

0.30

0.23

0.18

PIN 1

INDICATOR

PIN 1

INDICATOR

31

30

40

1

0.50

BSC

4.45

4.30 SQ

4.25

EXPOSED

PAD

21

20

10

11

0.45

0.40

0.35

0.25 MIN

TOP VIEW

BOTTOM VIEW

FOR PROPER CONNECTION OF

THE EXPOSED PAD, REFER TO

THE PIN CONFIGURATION AND

FUNCTION DESCRIPTIONS

0.80

0.75

0.70

0.05 MAX

0.02 NOM

SECTION OF THIS DATA SHEET.

COPLANARITY

0.08

0.20 REF

SEATING

PLANE

COMPLIANT TO JEDEC STANDARDS MO-220-WJJD.

Figure 99. 40-Lead Lead Frame Chip Scale Package [LFCSP_WQ]

6 mm x 6 mm Body, Very Very Thin Quad

(CP-40-10)

Dimensions shown in millimeters

ORDERING GUIDE

Model¹

Temperature Range

Package Description

Package Option

ADE7854ACPZ

ADE7854ACPZ-RL

ADE7858ACPZ

ADE7858ACPZ-RL

ADE7868ACPZ

ADE7868ACPZ-RL

ADE7878ACPZ

ADE7878ACPZ-RL

−40°C to +85°C

40-Lead LFCSP_WQ

40-Lead LFCSP_WQ, 13”Tape and Reel

40-Lead LFCSP_WQ

40-Lead LFCSP_WQ, 13”Tape and Reel

40-Lead LFCSP_WQ

40-Lead LFCSP_WQ, 13”Tape and Reel

40-Lead LFCSP_WQ

CP-40-10

40-Lead LFCSP_WQ, 13”Tape and Reel

¹Z = RoHS Compliant Part.

Rev. H| Page 98 of 100

Data Sheet

NOTES

ADE7854/ADE7858/ADE7868/ADE7878

Rev. H| Page 99 of 100

ADE7854/ADE7858/ADE7868/ADE7878

NOTES

Data Sheet

I²C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors).

registered trademarks are the property of their respective owners.

D08510-0-4/14(H)

Rev. H| Page 100 of 100


型号：	ADE7854ACPZ
厂家：	ADI
描述：	Polyphase Multifunction Energy Metering IC
文件：	总100页 (文件大小：1871K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

ADE7854ACPZ [ADI]

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