ADUC812BCPZ [ADI]
IC 8-BIT, FLASH, 11.0592 MHz, MICROCONTROLLER, PQCC56, LEAD FRAME, CSP-56, Microcontroller;型号: | ADUC812BCPZ |
厂家: | ADI |
描述: | IC 8-BIT, FLASH, 11.0592 MHz, MICROCONTROLLER, PQCC56, LEAD FRAME, CSP-56, Microcontroller 时钟 微控制器 外围集成电路 |
文件: | 总60页 (文件大小:1175K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
®
MicroConverter , Multichannel
a
12-Bit ADC with Embedded Flash MCU
ADuC812
FEATURES
APPLICATIONS
Analog I/O
Intelligent Sensors Calibration and Conditioning
Battery-Powered Systems (Portable PCs, Instruments,
Monitors)
8-Channel, High Accuracy 12-Bit ADC
On-Chip, 100 ppm/ꢁC Voltage Reference
High Speed 200 kSPS
Transient Capture Systems
DMA Controller for High Speed ADC-to-RAM Capture
2 12-Bit Voltage Output DACs
DAS and Communications Systems
Control Loop Monitors (Optical Networks/Base Stations)
On-Chip Temperature Sensor Function
Memory
GENERAL DESCRIPTION
The ADuC812 is a fully integrated 12-bit data acquisition system
incorporating a high performance self-calibrating multichannel
ADC, dual DAC, and programmable 8-bit MCU (8051 instruc-
tion set compatible) on a single chip.
8K Bytes On-Chip Flash/EE Program Memory
640 Bytes On-Chip Flash/EE Data Memory
256 Bytes On-Chip Data RAM
16M Bytes External Data Address Space
64K Bytes External Program Address Space
8051 Compatible Core
12 MHz Nominal Operation (16 MHz Max)
3 16-Bit Timer/Counters
High Current Drive Capability—Port 3
9 Interrupt Sources, 2 Priority Levels
Power
The programmable 8051 compatible core is supported by 8K
bytes Flash/EE program memory, 640 bytes Flash/EE data
memory, and 256 bytes data SRAM on-chip.
Additional MCU support functions include Watchdog Timer,
Power Supply Monitor, and ADC DMA functions. Thirty-two
programmable I/O lines, I2C compatible SPI and Standard
UART Serial Port I/O are provided for multiprocessor interfaces
and I/O expansion.
Specified for 3 V and 5 V Operation
Normal, Idle, and Power-Down Modes
On-Chip Peripherals
Normal, idle, and power-down operating modes for both the
MCU core and analog converters allow flexible power manage-
ment schemes suited to low power applications. The part is
specified for 3 V and 5 V operation over the industrial tem-
perature range and is available in a 52-lead, plastic quad
flatpack package, and in a 56-lead, chip scale package.
UART and SPI® Serial I/O
2-Wire (400 kHz I2C® Compatible) Serial I/O
Watchdog Timer
Power Supply Monitor
FUNCTIONAL BLOCK DIAGRAM
P0.0–P0.7
P1.0–P1.7
P2.0–P2.7
P3.0–P3.7
DAC0
BUF
BUF
DAC0
ADC
12-BIT
AIN0 (P1.0)–AIN7 (P1.7)
CONTROL
AND
CALIBRATION
LOGIC
DAC
CONTROL
SUCCESSIVE
AIN
MUX
T/H
APPROXIMATION
ADC
DAC1
DAC1
T0 (P3.4)
T1 (P3.5)
MICROCONTROLLER
T2 (P1.0)
T2EX (P1.1)
8051 BASED
MICROCONTROLLER CORE
POWER SUPPLY
MONITOR
3 ꢀ 16-BIT
TIMER/COUNTERS
2.5V
REF
TEMP
SENSOR
2-WIRE
SPI
8K ꢀ 8 PROGRAM
WATCHDOG
TIMER
INT0 (P3.2)
INT1 (P3.3)
ALE
FLASH EEPROM
SERIAL I/O
640 ꢀ 8 USER
FLASH EEPROM
UART
OSC
MUX
V
BUF
REF
PSEN
256 ꢀ 8 USER
EA
RAM
ADuC812
C
REF
RESET
XTAL1 XTAL2 RxD TxD
(P3.0) (P3.1)
SCLOCK
MISO
(P3.3)
AV
AGND DV
DGND
MOSI/
SDATA
DD
DD
REV. E
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, norforanyinfringementsofpatentsorotherrightsofthirdpartiesthat
may result from its use. 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 companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
Fax: 781/326-8703
www.analog.com
© 2003 Analog Devices, Inc. All rights reserved.
ADuC812
TABLE OF CONTENTS
FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
APPLICATONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . 6
PIN CONFIGURATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
PIN FUNCTION DESCRIPTIONS . . . . . . . . . . . . . . . . . . . . . 7
TERMINOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
ADC SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Integral Nonlinearity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Differential Nonlinearity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Offset Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Full-Scale Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Signal to (Noise + Distortion) Ratio . . . . . . . . . . . . . . . . . . . . 8
Total Harmonic Distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
DAC SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Relative Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Voltage Output Settling Time . . . . . . . . . . . . . . . . . . . . . . . . . 8
Digital-to-Analog Glitch Impulse . . . . . . . . . . . . . . . . . . . . . . . 8
ARCHITECTURE, MAIN FEATURES . . . . . . . . . . . . . . . . . . 9
MEMORY ORGANIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . 9
OVERVIEW OF MCU-RELATED SFRs . . . . . . . . . . . . . . . . . 10
Accumulator SFR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
B SFR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Stack Pointer SFR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Data Pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Program Status Word SFR . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Power Control SFR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
SPECIAL FUNCTION REGISTERS . . . . . . . . . . . . . . . . . . . 11
ADC CIRCUIT INFORMATION . . . . . . . . . . . . . . . . . . . . . . 12
General Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
ADC Transfer Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Typical Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
ADCCON1—(ADC Control SFR #1) . . . . . . . . . . . . . . . . . 13
ADCCON2—(ADC Control SFR #2) . . . . . . . . . . . . . . . . . 14
ADCCON3—(ADC Control SFR #3) . . . . . . . . . . . . . . . . . 14
Driving the ADC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Voltage Reference Connections . . . . . . . . . . . . . . . . . . . . . . . 16
Configuring the ADC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
ADC DMA Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
DMA Mode Configuration Example . . . . . . . . . . . . . . . . . . . 17
Micro Operation during ADC DMA Mode . . . . . . . . . . . . . . 17
Offset and Gain Calibration Coefficients . . . . . . . . . . . . . . . . 17
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
NONVOLATILE FLASH MEMORY . . . . . . . . . . . . . . . . . . . 18
Flash Memory Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Flash/EE Memory and the ADuC812 . . . . . . . . . . . . . . . . . . 18
ADuC812 Flash/EE Memory Reliability . . . . . . . . . . . . . . . . 18
Using the Flash/EE Program Memory . . . . . . . . . . . . . . . . . . 19
Using the Flash/EE Data Memory . . . . . . . . . . . . . . . . . . . . . 19
ECON—Flash/EE Memory Control SFR . . . . . . . . . . . . . . . 20
Flash/EE Memory Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Using the Flash/EE Memory Interface . . . . . . . . . . . . . . . . . . 20
Erase-All . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Program a Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
USER INTERFACE TO OTHER ON-CHIP
WATCHDOG TIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
POWER SUPPLY MONITOR . . . . . . . . . . . . . . . . . . . . . . . . . 24
SERIAL PERIPHERAL INTERFACE . . . . . . . . . . . . . . . . . . . 25
MISO (Master In, Slave Out Data I/O Pin) . . . . . . . . . . . . . . 25
MOSI (Master Out, Slave In Pin) . . . . . . . . . . . . . . . . . . . . . 26
SCLOCK (Serial Clock I/O Pin) . . . . . . . . . . . . . . . . . . . . . . 26
SS (Slave Select Input Pin) . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Using the SPI Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
SPI Interface—Master Mode . . . . . . . . . . . . . . . . . . . . . . . . . 27
SPI Interface—Slave Mode . . . . . . . . . . . . . . . . . . . . . . . . . . 27
I2C COMPATIBLE INTERFACE . . . . . . . . . . . . . . . . . . . . . . 28
8051 COMPATIBLE ON-CHIP PERIPHERALS . . . . . . . . . . 29
Parallel I/O Ports 0–3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Timers/Counters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Timer/Counters 0 and 1 Data Registers . . . . . . . . . . . . . . . . . 31
TH0 and TL0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
TH1 and TL1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
TIMER/COUNTERS 0 AND 1 OPERATING MODES . . . . . 32
Mode 0 (13-Bit Timer/Counter) . . . . . . . . . . . . . . . . . . . . . . 32
Mode 1 (16-Bit Timer/Counter) . . . . . . . . . . . . . . . . . . . . . . 32
Mode 2 (8-Bit Timer/Counter with Auto Reload) . . . . . . . . . 32
Mode 3 (Two 8-Bit Timer/Counters) . . . . . . . . . . . . . . . . . . 32
Timer/Counter 2 Data Registers . . . . . . . . . . . . . . . . . . . . . . 33
TH2 and TL2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
RCAP2H and RCAP2L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Timer/Counter Operation Modes . . . . . . . . . . . . . . . . . . . . . 34
16-Bit Autoreload Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
16-Bit Capture Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
UART SERIAL INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . 35
Mode 0 (8-Bit Shift Register Mode) . . . . . . . . . . . . . . . . . . . 36
Mode 1 (8-Bit UART, Variable Baud Rate) . . . . . . . . . . . . . . 36
Mode 2 (9-Bit UART with Fixed Baud Rate) . . . . . . . . . . . . 36
Mode 3 (9-Bit UART with Variable Baud Rate) . . . . . . . . . . 36
UART Serial Port Baud Rate Generation . . . . . . . . . . . . . . . 36
Timer 1 Generated Baud Rates . . . . . . . . . . . . . . . . . . . . . . . 37
Timer 2 Generated Baud Rates . . . . . . . . . . . . . . . . . . . . . . . 37
INTERRUPT SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Interrupt Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Interrupt Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
ADuC812 HARDWARE DESIGN CONSIDERATIONS . . . . 40
Clock Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
External Memory Interface . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Power-On Reset Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Power Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Grounding and Board Layout Recommendations . . . . . . . . . 43
OTHER HARDWARE CONSIDERATIONS . . . . . . . . . . . . . 44
In-Circuit Serial Download Access . . . . . . . . . . . . . . . . . . . . 44
Embedded Serial Port Debugger . . . . . . . . . . . . . . . . . . . . . . 44
Single-Pin Emulation Mode . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Enhanced-Hooks Emulation Mode . . . . . . . . . . . . . . . . . . . . 45
Typical System Configuration . . . . . . . . . . . . . . . . . . . . . . . . 45
QUICKSTART DEVELOPMENT SYSTEM . . . . . . . . . . . . . 45
Download—In-Circuit Serial Downloader . . . . . . . . . . . . . . . 45
DeBug—In-Circuit Debugger . . . . . . . . . . . . . . . . . . . . . . . . 45
ADSIM—Windows Simulator . . . . . . . . . . . . . . . . . . . . . . . . 45
TIMING SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . 46
OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
ADuC812 PERIPHERALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Using the DAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
–2–
REV. E
ADuC812
SPECIFICATIONS1, 2
(AVDD = DVDD = 3.0 V or 5.0 V ꢂ 10%, REFIN /REFOUT = 2.5 V Internal Reference, MCLKIN = 11.0592 MHz,
fSAMPLE = 200 kHz, DAC VOUT Load to AGND; RL = 2 kꢃ, CL = 100 pF. All specifications TA = TMIN to TMAX, unless otherwise noted.)
ADuC812BS
Parameter
VDD = 5 V
VDD = 3 V
Unit
Test Conditions/Comments
ADC CHANNEL SPECIFICATIONS
DC ACCURACY3, 4
Resolution
Integral Nonlinearity
12
1/2
1.5
1.5
1
12
1/2
1.5
1.5
1
Bits
LSB typ
LSB max
LSB typ
LSB typ
fSAMPLE = 100 kHz
fSAMPLE = 100 kHz
f
SAMPLE = 200 kHz
fSAMPLE = 100 kHz. Guaranteed No
Missing Codes at 5 V
Differential Nonlinearity
CALIBRATED ENDPOINT ERRORS5, 6
Offset Error
5
1
5
1
LSB max
LSB typ
LSB typ
LSB max
LSB typ
LSB typ
Offset Error Match
Gain Error
1
1
6
1
1.5
6
1
1.5
Gain Error Match
USER SYSTEM CALIBRATION7
Offset Calibration Range
Gain Calibration Range
5
2.5
±±
2.5
% of VREF typ
% of VREF typ
DYNAMIC PERFORMANCE
fIN = 10 kHz Sine Wave
f
SAMPLE = 100 kHz
Signal-to-Noise Ratio (SNR)8
Total Harmonic Distortion (THD)
Peak Harmonic or Spurious Noise
70
–78
–78
70
–78
–78
dB typ
dB typ
dB typ
ANALOG INPUT
Input Voltage Ranges
Leakage Current
0 to VREF
0 to VREF
V
1
0.1
20
1
0.1
20
µA max
µA typ
pF max
Input Capacitance9
TEMPERATURE SENSOR10
Voltage Output at 25°C
Voltage TC
600
–3.0
600
–3.0
mV typ
mV/°C typ
Can vary significantly (> 20%)
from device to device
DAC CHANNEL SPECIFICATIONS
DC ACCURACY11
Resolution
12
3
12
3
1
60
15
30
10
0.5
Bits
Relative Accuracy
Differential Nonlinearity
Offset Error
LSB typ
LSB typ
mV max
mV typ
mV max
mV typ
% typ
0.5
60
15
30
10
0.5
Guaranteed 12-Bit Monotonic
% of Full-Scale on DAC1
Full-Scale Error
Full-Scale Mismatch
ANALOG OUTPUTS
Voltage Range_0
Voltage Range_1
Resistive Load
Capacitive Load
Output Impedance
ISINK
0 to VREF
0 to VDD
10
100
0.5
0 to VREF
0 to VDD
10
100
0.5
V typ
V typ
kΩ typ
pF typ
Ω typ
µA typ
50
50
–3–
REV. E
ADuC812
SPECIFICATIONS1, 2 (continued)
ADuC812BS
VDD = 5 V VDD = 3 V
Parameter
Unit
Test Conditions/Comments
DAC AC CHARACTERISTICS
Voltage Output Settling Time
15
10
15
10
µs typ
Full-Scale Settling Time to
within 1/2 LSB of Final Value
1 LSB Change at Major Carry
Digital-to-Analog Glitch Energy
nV sec typ
REFERENCE INPUT/OUTPUT
REFIN Input Voltage Range9
Input Impedance
2.3/VDD
150
2.5 2.5%
2.5
2.3/VDD
150
2.5 2.5%
2.5
V min/max
kΩ typ
V min/max
V typ
REFOUT Output Voltage
Initial Tolerance @ 25°C
REFOUT Tempco
100
100
ppm/°C typ
FLASH/EE MEMORY PERFORMANCE
CHARACTERISTICS12, 13
Endurance
10,000
50,000
10
Cycles min
Cycles typ
Years min
50,000
Data Retention
WATCHDOG TIMER
CHARACTERISTICS
Oscillator Frequency
64
64
kHz typ
POWER SUPPLY MONITOR
CHARACTERISTICS
Power Supply Trip Point Accuracy
2.5
2.5
% of Selected
Nominal Trip
Point Voltage
max
1.0
1.0
% of Selected
Nominal Trip
Point Voltage
typ
DIGITAL INPUTS
Input High Voltage (VINH
XTAL1 Input High Voltage (VINH) Only
Input Low Voltage (VINL
)
2.4
4
0.8
10
1
2.4
V min
V min
V max
µA max
µA typ
)
0.8
10
1
Input Leakage Current (Port 0, EA)
V
IN = 0 V or VDD
VIN = 0 V or VDD
Logic 1 Input Current
(All Digital Inputs)
10
1
–80
–40
10
1
µA max
µA typ
µA max
µA typ
µA max
µA typ
pF typ
V
IN = VDD
VIN = VDD
Logic 0 Input Current (Port 1, 2, 3)
–40
–20
–500
–200
10
V
IL = 450 mV
Logic 1-0 Transition Current (Port 1, 2, 3) –700
–400
Input Capacitance
VIL = 2 V
VIL = 2 V
10
–4–
REV. E
ADuC812
ADuC812BS
VDD = 5 V VDD = 3 V
Parameter
Unit
Test Conditions/Comments
DIGITAL OUTPUTS
Output High Voltage (VOH
)
2.4
4.0
2.4
2.6
V min
V typ
VDD = 4.5 V to 5.5 V
ISOURCE = 80 µA
VDD = 2.7 V to 3.3 V
ISOURCE = 20 µA
Output Low Voltage (VOL
ALE, PSEN, Ports 0 and 2
)
0.4
0.2
0.4
0.2
0.4
0.2
0.4
0.2
V max
V typ
V max
V typ
ISINK = 1.6 mA
ISINK = 1.6 mA
ISINK = 8 mA
ISINK = 8 mA
Port 3
Floating State Leakage Current
Floating State Output Capacitance
10
1
10
10
1
10
µA max
µA typ
pF typ
POWER REQUIREMENTS14, 15, 16
IDD Normal Mode17
43
32
26
8
25
18
15
7
25
16
12
3
10
6
6
2
15
5
mA max
mA typ
mA typ
mA typ
mA max
mA typ
mA typ
mA typ
µA max
µA typ
MCLKIN = 16 MHz
MCLKIN = 16 MHz
MCLKIN = 12 MHz
MCLKIN = 1 MHz
MCLKIN = 16 MHz
MCLKIN = 16 MHz
MCLKIN = 12 MHz
MCLKIN = 1 MHz
IDD Idle Mode
IDD Power-Down Mode18
30
5
NOTES
1Specifications apply after calibration.
2Temperature range –40°C to +85°C.
3Linearity is guaranteed during normal MicroConverter core operation.
4Linearity may degrade when programming or erasing the 640 byte Flash/EE space during ADC conversion times due to on-chip charge pump activity.
5Measured in production at VDD = 5 V after Software Calibration Routine at 25°C only.
6User may need to execute Software Calibration Routine to achieve these specifications, which are configuration dependent.
7The offset and gain calibration spans are defined as the voltage range of user system offset and gain errors that the ADuC812 can compensate.
8SNR calculation includes distortion and noise components.
9Specification is not production tested, but is supported by characterization data at initial product release.
10The temperature sensor will give a measure of the die temperature directly; air temperature can be inferred from this result.
11DAC linearity is calculated using:
Reduced code range of 48 to 4095, 0 to VREF range
Reduced code range of 48 to 3995, 0 to VDD range
DAC output load = 10 kΩ and 50 pF.
12Flash/EE Memory Performance Specifications are qualified as per JEDEC Specification (Data Retention) and JEDEC Draft Specification A117 (Endurance).
13Endurance Cycling is evaluated under the following conditions:
Mode
= Byte Programming, Page Erase Cycling
Cycle Pattern
Erase Time
Program Time
= 00H to FFH
= 20 ms
= 100 µs
14
I
at other MCLKIN frequencies is typically given by:
DD
Normal Mode (VDD = 5 V):
Normal Mode (VDD = 3 V):
Idle Mode (VDD = 5 V):
Idle Mode (VDD = 3 V):
IDD = (1.6 nAs × MCLKIN) + 6 mA
IDD = (0.8 nAs × MCLKIN) + 3 mA
IDD = (0.75 nAs × MCLKIN) + 6 mA
IDD = (0.25 nAs × MCLKIN) + 3 mA
where MCLKIN is the oscillator frequency in MHz and resultant IDD values are in mA.
15
16
I
I
currents are expressed as a summation of analog and digital power supply currents during normal MicroConverter operation.
is not measured during Flash/EE program or erase cycles; IDD will typically increase by 10 mA during these cycles.
DD
DD
17Analog IDD = 2 mA (typ) in normal operation (internal VREF, ADC, and DAC peripherals powered on).
18EA = Port0 = DVDD, XTAL1 (Input) tied to DVDD, during this measurement.
Typical specifications are not production tested, but are supported by characterization data at initial product release.
Timing Specifications—See Pages 46–55.
Specifications subject to change without notice.
Please refer to User Guide, Quick Reference Guide, Application Notes, and Silicon Errata Sheet at www.analog.com/microconverter for additional information.
–5–
REV. E
ADuC812
ABSOLUTE MAXIMUM RATINGS*
(TA = 25°C, unless otherwise noted.)
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . 150°C
θ
JA Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . . 90°C/W
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
AVDD to DVDD . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +0.3 V
AGND to DGND . . . . . . . . . . . . . . . . . . . . –0.3 V to +0.3 V
DVDD to DGND, AVDD to AGND . . . . . . . . . –0.3 V to +7 V
Digital Input Voltage to DGND . . . –0.3 V to DVDD + 0.3 V
Digital Output Voltage to DGND . . –0.3 V to DVDD + 0.3 V
VREF to AGND . . . . . . . . . . . . . . . . . –0.3 V to AVDD + 0.3 V
Analog Inputs to AGND . . . . . . . . . . –0.3 V to AVDD + 0.3 V
Operating Temperature Range Industrial (B Version)
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent 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.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C
PIN CONFIGURATIONS
52-Lead MQFP
56-Lead LFCSP
52 51 50 49 48 47 46 45 44 43 42 41 40
P1.1/ADC1/T2EX
P1.2/ADC2
1
2
42
P2.7/A15/A23
P2.6/A14/A22
P2.5/A13/A21
1
2
39
38
37
36
35
34
33
32
31
30
29
28
27
P1.0/ADC0/T2
P1.1/ADC1/T2EX
P1.2/ADC2
P2.7/A15/A23
P2.6/A14/A22
P2.5/A13/A21
P2.4/A12/A20
DGND
PIN 1
INDENTIFIER
PIN 1
IDENTIFIER
41
40
39
38
37
P1.3/ADC3
3
3
AV
DD
4
P2.4/A12/A20
DGND
4
P1.3/ADC3
AV
DD
5
5
AV
DD
AGND
6
DGND
6
DV
DD
AGND
ADuC812
TOP VIEW
(Not to Scale)
ADuC812
AGND
AGND
7
36
35
34
33
32
DV
DD
7
XTAL2
C
V
REF
TOP VIEW
8
XTAL2
(Not to Scale)
8
XTAL1
REF
C
9
XTAL1
REF
9
DAC0
DAC1
P2.3/A11/A19
P2.2/A10/A18
P2.1/A9/A17
P2.0/A8/A16
SDATA/MOSI
V
10
11
12
REF
P2.3/A11/A19
P2.2/A10/A18
10
11
12
13
DAC0
P1.4/ADC4
DAC1
P1.4/ADC4
P2.1/A9/A17
31
30
29
P1.5/ADC5/SS
13
14
P2.0/A8/A16
SDATA/MOSI
P1.6/ADC6
P1.5/ADC5/SS
14 15 16 17 18 19 20 21 22 23 24 25 26
ORDERING GUIDE
Temperature
Range
Package
Description
Package
Option
Model
ADuC812BS
ADuC812BS
EVAL-ADuC812QS
EVAL-ADuC812QSP
–40°C to +85°C
–40°C to +85°C
52-Lead Metric Quad Flat Package
56-Lead Lead Frame Chip Scale Package CP-56
QuickStart Development System
S-52
QuickStart Development System Plus
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the ADuC812 features proprietary ESD protection circuitry, permanent damage may occur on
devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are
recommended to avoid performance degradation or loss of functionality.
–6–
REV. E
ADuC812
PIN FUNCTION DESCRIPTIONS
Mnemonic
Type Function
DVDD
AVDD
CREF
VREF
P
P
I
I/O
Digital Positive Supply Voltage, 3 V or 5 V Nominal.
Analog Positive Supply Voltage, 3 V or 5 V Nominal.
Decoupling Input for On-Chip Reference. Connect 0.1 µF between this pin and AGND.
Reference Input/Output. This pin is connected to the internal reference through a series resistor and is the
reference source for the ADC. The nominal internal reference voltage is 2.5 V, which appears at the pin.
This pin can be overdriven by an external reference.
AGND
P1.0–P1.7
G
I
Analog Ground. Ground reference point for the analog circuitry.
Port 1 is an 8-bit input port only. Unlike other ports, Port 1 defaults to Analog Input mode. To configure
any of these Port Pins as a digital input, write a 0 to the port bit. Port 1 pins are multifunctional and share
the following functionality.
ADC0–ADC7
T2
I
I
Analog Inputs. Eight single-ended analog inputs. Channel selection is via ADCCON2 SFR.
Timer 2 Digital Input. Input to Timer/Counter 2. When enabled, Counter 2 is incremented in response to a
1 to 0 transition of the T2 input.
T2EX
I
Digital Input. Capture/Reload trigger for Counter 2; also functions as an Up/Down control input for
Counter 2.
SS
I
Slave Select Input for the SPI Interface.
SDATA
SCLOCK
MOSI
MISO
DAC0
DAC1
RESET
I/O
I/O
I/O
I/O
O
User selectable, I2C Compatible or SPI Data Input/Output Pin.
Serial Clock Pin for I2C Compatible or SPI Serial Interface Clock.
SPI Master Output/Slave Input Data I/O Pin for SPI Interface.
SPI Master Input/Slave Output Data I/O Pin for SPI Serial Interface.
Voltage Output from DAC0.
O
I
Voltage Output from DAC1.
Digital Input. A high level on this pin for 24 master clock cycles while the oscillator is running resets the
device. External power-on reset (POR) circuity must be implemented to drive the RESET pin as described
in the Power-On Reset Operation section.
P3.0–P3.7
I/O
Port 3 is a bidirectional port with internal pull-up resistors. Port 3 pins that have 1s written to them are
pulled high by the internal pull-up resistors; in that state they can be used as inputs. As inputs, Port 3 pins
being pulled externally low will source current because of the internal pull-up resistors. Port 3 pins also
contain various secondary functions that are described below.
RxD
TxD
INT0
I/O
O
I
Receiver Data Input (Asynchronous) or Data Input/Output (Synchronous) of Serial (UART) Port
Transmitter Data Output (Asynchronous) or Clock Output (Synchronous) of Serial (UART) Port
Interrupt 0, programmable edge or level triggered Interrupt input, INT0 can be programmed to one of two
priority levels. This pin can also be used as a gate control input to Timer 0.
INT1
I
Interrupt 1, programmable edge or level triggered Interrupt input, INT1 can be programmed to one of two
priority levels. This pin can also be used as a gate control input to Timer 1.
T0
T1
CONVST
I
I
I
Timer/Counter 0 Input.
Timer/Counter 1 Input.
Active Low Convert Start Logic Input for the ADC Block when the External Convert Start Function is Enabled.
A low-to-high transition on this input puts the track-and-hold into its hold mode and starts conversion.
WR
O
O
O
I
G
I/O
Write Control Signal, Logic Output. Latches the data byte from Port 0 into the external data memory.
Read Control Signal, Logic Output. Enables the external data memory to Port 0.
Output of the Inverting Oscillator Amplifier.
Input to the Inverting Oscillator Amplifier and to the Internal Clock Generator Circuits.
Digital Ground. Ground reference point for the digital circuitry.
Port 2 is a bidirectional port with internal pull-up resistors. Port 2 pins that have 1s written to them are
pulled high by the internal pull-up resistors; in that state they can be used as inputs. As inputs, Port 2
pins being pulled externally low will source current because of the internal pull-up resistors. Port 2 emits the
high order address bytes during fetches from external program memory and middle and high order address
bytes during accesses to the external 24-bit external data memory space.
RD
XTAL2
XTAL1
DGND
P2.0–P2.7
(A8–A15)
(A16–A23)
REV. E
–7–
ADuC812
PIN FUNCTION DESCRIPTIONS (continued)
Mnemonic
Type Function
PSEN
O
Program Store Enable, Logic Output. This output is a control signal that enables the external program
memory to the bus during external fetch operations. It is active every six oscillator periods except during
external data memory accesses. This pin remains high during internal program execution. PSEN can also be
used to enable serial download mode when pulled low through a resistor on power-up or RESET.
ALE
O
I
Address Latch Enable, Logic Output. This output is used to latch the low byte (and page byte for 24-bit
address space accesses) of the address into external memory during normal operation. It is activated every
six oscillator periods except during an external data memory access.
External Access Enable, Logic Input. When held high, this input enables the device to fetch code from
internal program memory locations 0000H to 1FFFH. When held low, this input enables the device to fetch
all instructions from external program memory.
EA
P0.7–P0.0
(A0–A7)
I/O
Port 0 is an 8-bit open-drain bidirectional I/O port. Port 0 pins that have 1s written to them float and in
that state can be used as high impedance inputs. Port 0 is also the multiplexed low order address and data
bus during accesses to external program or data memory. In this application, it uses strong internal pull-ups
when emitting 1s.
TERMINOLOGY
dependent upon the number of quantization levels in the digiti-
ADC SPECIFICATIONS
Integral Nonlinearity
zation process; the more levels, the smaller the quantization
noise. The theoretical signal-to-(noise + distortion) ratio for an
ideal N-bit converter with a sine wave input is given by:
This is the maximum deviation of any code from a straight line
passing through the endpoints of the ADC transfer function.
The endpoints of the transfer function are zero scale, a point
1/2 LSB below the first code transition, and full scale, a point
1/2 LSB above the last code transition.
Signal-to-(Noise + Distortion) = (6.02N + 1.76) dB
Thus for a 12-bit converter, this is 74 dB.
Total Harmonic Distortion
Total Harmonic Distortion is the ratio of the rms sum of the
harmonics to the fundamental.
Differential Nonlinearity
This is the difference between the measured and the ideal 1 LSB
change between any two adjacent codes in the ADC.
DAC SPECIFICATIONS
Relative Accuracy
Relative accuracy or endpoint linearity is a measure of the
maximum deviation from a straight line passing through the
endpoints of the DAC transfer function. It is measured after
adjusting for zero-scale error and full-scale error.
Offset Error
This is the deviation of the first code transition (0000 . . . 000)
to (0000 . . . 001) from the ideal, i.e., +1/2 LSB.
Full-Scale Error
This is the deviation of the last code transition from the ideal
AIN voltage (Full Scale – 1.5 LSB) after the offset error has
been adjusted out.
Voltage Output Settling Time
This is the amount of time it takes for the output to settle to a
specified level for a full-scale input change.
Signal-to-(Noise + Distortion) Ratio
This is the measured ratio of signal-to-(noise + distortion) at the
output of the ADC. The signal is the rms amplitude of the fun-
damental. Noise is the rms sum of all nonfundamental signals up
to half the sampling frequency (fS/2), excluding dc. The ratio is
Digital-to-Analog Glitch Impulse
This is the amount of charge injected into the analog output
when the inputs change state. It is specified as the area of the
glitch in nV sec.
–8–
REV. E
ADuC812
ARCHITECTURE, MAIN FEATURES
7FH
2FH
The ADuC812 is a highly integrated, true 12-bit data acquisi-
tion system. At its core, the ADuC812 incorporates a high
performance 8-bit (8052 compatible) MCU with on-chip
reprogrammable nonvolatile Flash program memory control-
ling a multichannel (eight input channels) 12-bit ADC.
BANKS
SELECTED
VIA
BIT ADDRESSABLE SPACE
(BIT ADDRESSES 0FH–7FH)
The chip incorporates all secondary functions to fully support
the programmable data acquisition core. These secondary
functions include User Flash Memory, Watchdog Timer
(WDT), Power Supply Monitor (PSM), and various industry-
standard parallel and serial interfaces.
20H
18H
10H
08H
00H
BITS IN PSW
1FH
17H
0FH
07H
11
10
4 BANKS OF 8 REGISTERS
R0–R7
PROGRAM MEMORY SPACE
READ ONLY
01
00
RESET VALUE OF
STACK POINTER
FFFFH
EXTERNAL
PROGRAM
MEMORY
SPACE
Figure 2. Lower 128 Bytes of Internal RAM
MEMORY ORGANIZATION
As with all 8052 compatible devices, the ADuC812 has separate
address spaces for program and data memory as shown in Fig-
ure 1. Also as shown in Figure 1, an additional 640 bytes of
User Data Flash EEPROM are available to the user. The User
Data Flash Memory area is accessed indirectly via a group of
control registers mapped in the Special Function Register (SFR)
area in the Data Memory Space.
2000H
1FFFH
EA = 1
EA = 0
EXTERNAL
PROGRAM
MEMORY
SPACE
INTERNAL
8K BYTE
FLASH/EE
PROGRAM
MEMORY
The SFR space is mapped in the upper 128 bytes of internal data
memory space. The SFR area is accessed by direct addressing
only and provides an interface between the CPU and all on-chip
peripherals. A block diagram showing the programming model
of the ADuC812 via the SFR area is shown in Figure 3.
0000H
DATA MEMORY SPACE
READ/WRITE
FFFFFFH
9FH
(PAGE 159)
640 BYTES
FLASH/EE DATA
MEMORY
8K BYTE
ELECTRICALLY
640-BYTE
REPROGRAMMABLE
ELECTRICALLY
ACCESSED
INDIRECTLY
VIA SFR
NONVOLATILE
REPROGRAMMABLE
FLASH/EE PROGRAM
NONVOLATILE
CONTROL REGISTERS
MEMORY
FLASH/EE DATA
MEMORY
00H
(PAGE 0)
128-BYTE
AUTOCALIBRATING
EXTERNAL
DATA
SPECIAL
8051
INTERNAL
DATA MEMORY
SPACE
8-CHANNEL
FUNCTION
COMPATIBLE
MEMORY
SPACE
HIGH SPEED
12-BIT ADC
REGISTER
CORE
AREA
(24-BIT
ADDRESS
SPACE)
FFH
SPECIAL
FUNCTION
REGISTERS
ACCESSIBLE
BY DIRECT
ADDRESSING
ONLY
FFH
ACCESSIBLE
OTHER ON-CHIP
PERIPHERALS
TEMPERATURE
SENSOR
BY
INDIRECT
ADDRESSING
ONLY
UPPER
128
2 ꢀ 12-BIT DACs
SERIAL I/O
PARALLEL I/O
WDT
80H
80H
7FH
ACCESSIBLE
BY
LOWER
128
DIRECT
PSM
AND
INDIRECT
ADDRESSING
00H
000000H
Figure 3. Programming Model
Figure 1. Program and Data Memory Maps
The lower 128 bytes of internal data memory are mapped as
shown in Figure 2. The lowest 32 bytes are grouped into four
banks of eight registers addressed as R0 through R7. The next
16 bytes (128 bits) above the register banks form a block of
bit addressable memory space at bit addresses 00H through 7FH.
REV. E
–9–
ADuC812
OVERVIEW OF MCU-RELATED SFRs
Power Control SFR
Accumulator SFR
The Power Control (PCON) register contains bits for power
saving options and general-purpose status flags as shown in
Table II.
ACC is the Accumulator register and is used for math opera-
tions including addition, subtraction, integer multiplication and
division, and Boolean bit manipulations. The mnemonics for
accumulator-specific instructions refer to the Accumulator as A.
SFR Address
87H
00H
No
Power-On Default Value
Bit Addressable
B SFR
The B register is used with the ACC for multiplication and
division operations. For other instructions, it can be treated as a
general-purpose scratch pad register.
SMOD ALEOFF GF1
GF0
PD
IDL
Stack Pointer SFR
The SP register is the stack pointer and is used to hold an internal
RAM address that is called the “top of the stack.” The SP register
is incremented before data is stored during PUSH and CALL
executions. While the stack may reside anywhere in on-chip RAM,
the SP register is initialized to 07H after a reset. This causes the
stack to begin at location 08H.
Table II. PCON SFR Bit Designations
Bit
Name
Description
7
6
5
4
3
2
1
0
SMOD
———
———
ALEOFF
GF1
Double UART Baud Rate
Reserved
Reserved
Disable ALE Output
General-Purpose Flag Bit
General-Purpose Flag Bit
Power-Down Mode Enable
Idle Mode Enable
Data Pointer
The Data Pointer is made up of three 8-bit registers: DPP (page
byte), DPH (high byte), and DPL (low byte). These are used to
provide memory addresses for internal and external code access
and external data access. It may be manipulated as a 16-bit
register (DPTR = DPH, DPL), although INC DPTR instructions
will automatically carry over to DPP, or as three independent
8-bit registers (DPP, DPH, and DPL).
GF0
PD
IDL
Program Status Word SFR
The PSW register is the Program Status Word that contains
several bits reflecting the current status of the CPU as detailed
in Table I.
SFR Address
Power-On Default Value
Bit Addressable
D0H
00H
Yes
CY
AC
F0
RS1
RS0
OV
F1
P
Table I. PSW SFR Bit Designations
Bit
Name
CY
AC
F0
RS1
RS0
Description
7
6
5
4
3
Carry Flag
Auxiliary Carry Flag
General-Purpose Flag
Register Bank Select Bits
RS1
0
RS0
0
Selected Bank
0
1
2
3
0
1
1
0
1
1
2
1
0
OV
F1
P
Overflow Flag
General-Purpose Flag
Parity Bit
–10–
REV. E
ADuC812
SPECIAL FUNCTION REGISTERS
All registers except the program counter and the four general-purpose register banks reside in the special function register (SFR) area.
The SFR registers include control, configuration, and data registers that provide an interface between the CPU and other on-chip
peripherals.
Figure 4 shows a full SFR memory map and SFR contents on reset. Unoccupied SFR locations are shown dark shaded (NOT USED).
Unoccupied locations in the SFR address space are not implemented, i.e., no register exists at this location. If an unoccupied
location is read, an unspecified value is returned. SFR locations reserved for on-chip testing are shown lighter shaded (RESERVED)
and should not be accessed by user software. Sixteen of the SFR locations are also bit addressable and denoted by “1” i.e., the bit
addressable SFRs are those whose address ends in 0H or 8H.
SPICON1
ISPI
FFH
WCOL
SPE
FDH
SPIM
FCH
CPOL CPHA SPR1
SPR0
DAC0L
DAC0H
DAC1L
DAC1H
DACCON
FDH
04H
BITS
RESERVED
RESERVED
NOT USED
0
0
0
0
0
0
0
FEH
0
0
0
0
0
0
0
0
0
FBH
0
FAH
0
F9H
0
F8H
0
F8H
00H F9H 00H FAH 00H FBH 00H FCH 00H
ADCOFSL2 ADCOFSH2 ADCGAINL2 ADCGAINH2 ADCCON3
B1
SPIDAT
F7H 00H
ADCCON1
EFH 20H
BITS
BITS
F7H
MDO
F6H
0
0
0
F5H
MCO
F4H
MDI
F3H
0
F2H
0
F1H
0
F0H
0
0
0
0
0
F0H 00H F1H 00H F2H 20H F3H 00H F4H 00H F5H 00H
I2CCON1
MDE
EEH
I2CM I2CRS I2CTX
I2CI
E8H
RESERVED RESERVED RESERVED RESERVED RESERVED RESERVED
RESERVED RESERVED RESERVED RESERVED RESERVED RESERVED
EFH
EDH
ECH
EBH
0
0
0
0
EAH
0
0
0
0
0
E9H
0
0
0
0
E8H 00H
ACC1
RESERVED
BITS
BITS
BITS
BITS
BITS
BITS
BITS
BITS
BITS
BITS
BITS
BITS
BITS
E7H
E6H
E5H
E4H
E3H
E2H
E1H
E0H
E0H
00H
ADCCON21 ADCDATAL ADCDATAH
D8H 00H D9H 00H DAH 00H
PSMCON
DFH DEH
ADCI
DFH
DMA CCONV SCONV CS3
CS2
DAH
CS1
D9H
CS0
D8H
RESERVED RESERVED RESERVED RESERVED
DEH
0
0
0
DDH
0
DCH
0
DBH
PSW1
D0H 00H
T2CON1
C8H 00H
WDCON1
C0H 00H
IP1
DMAL
D2H 00H D3H 00H D4H 00H
RCAP2L RCAP2H TL2
DMAH
DMAP
CY
D7H
AC
D6H
F0
D5H
RS1
D4H
RS0
D3H
OV
D2H
FI
D1H
P
D0H
RESERVED
RESERVED
RESERVED RESERVED
RESERVED
RESERVED
0
0
TH2
TF2
CFH
EXF2
CEH
RCLK
CDH
TCLK EXEN2
CCH
TR2
CAH
CNT2 CAP2
C9H
RESERVED
0
0
CBH
0
0
C8H
0
CAH 00H CBH 00H CCH 00H CDH 00H
ETIM3
EDARL
PRE2
C7H
PRE1
PRE0
WDR1 WDR2 WDS
WDE
C0H
NOT USED
ECON
NOT USED
NOT USED
RESERVED
RESERVED
EDATA4
0
C6H
0
C5H
0
C4H
0
0
C3H
0
C2H
0
C1H
0
0
0
0
C4H C9H
EDATA1
C6H 00H
ETIM1
ETIM2
EDATA2
EDATA3
PSI
BFH
PADC
PT2
BDH
PS
BCH
PT1
BBH
PX1
BAH
PT0
B9H
PX0
B8H
0
1
0
1
0
1
0
1
BEH
0
0
1
0
1
0
1
0
1
0
0
B8H 00H B9H 00H BAH 52H BBH 04H BCH 00H BDH 00H BEH 00H BFH 00H
P31
RD
B7H
WR
B6H
T1
B5H
T0
B4H
INT1
B3H
INT0
B2H
TxD
B1H
RxD
B0H
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
NOT USED
1
1
0
1
0
1
0
1
1
0
1
0
1
0
1
1
0
1
0
1
0
1
1
0
1
0
1
0
1
1
0
1
0
1
0
1
B0H FFH
IE1
IE2
EA
EADC
ET2
ES
ET1
EX1
ET0
EX0
NOT USED
NOT USED
NOT USED
AFH
A7H
AEH
A6H
0
ADH
A5H
ACH
A4H
ABH
A3H
AAH
A2H
A9H
A1H
A8H
A0H
A8H 00H A9H 00H
P21
NOT USED
NOT USED
I2CDAT
NOT USED
I2CADD
NOT USED
1
0
1
0
1
A0H FFH
SCON1
SBUF
SM0
SM1
SM2
REN
TB8
RB8
TI
99H
RI
98H
NOT USED
9FH
97H
9EH
96H
9DH
95H
9CH
94H
9BH
93H
9AH
92H
98H 00H 99H 00H 9AH 00H 9BH 55H
P11, 3
T2EX
91H
T2
90H
NOT USED
NOT USED
NOT USED
NOT USED
TH0
NOT USED
TH1
NOT USED
90H FFH
TCON1
TMOD
TL0
TL1
TF1
8FH
TR1
8EH
TF0
8DH
TR0
8CH
IE1
8BH
IT1
8AH
IE0
89H
IT0
88H
NOT USED
88H 00H 89H 00H 8AH 00H 8BH 00H 8CH 00H 8DH 00H
P01
SP
DPL
DPH
DPP
PCON
RESERVED RESERVED
87H
86H
85H
84H
83H
82H
81H
80H
80H FFH 81H 07H 82H 00H 83H 00H 84H 00H
87H 00H
SFR MAP KEY:
THESE BITS ARE CONTAINED IN THIS BYTE.
TCON
MNEMONIC
IT0
88H
MNEMONIC
SFR ADDRESS
IE0
89H
0
0
DEFAULT VALUE
88H 00H
DEFAULT VALUE
SFR ADDRESS
SFR NOTES
1
SFRsWHOSE ADDRESS ENDS IN 0H OR 8H ARE BIT ADDRESSABLE.
2
CALIBRATION COEFFICIENTS ARE PRECONFIGURED ON POWER-UPTO FACTORY CALIBRATEDVALUES.
3
THE PRIMARY FUNCTION OF PORT 1 IS AS AN ANALOG INPUT PORT; THEREFORE, TO ENABLETHE DIGITAL SECONDARY FUNCTIONS
ONTHESE PORT PINS, WRITE A “0” TOTHE CORRESPONDING PORT 1 SFR BIT.
Figure 4. Special Function Register Locations and Reset Values
REV. E
–11–
ADuC812
ADC CIRCUIT INFORMATION
ADC Transfer Function
General Overview
The analog input range for the ADC is 0 V to VREF. For this
range, the designed code transitions occur midway between
successive integer LSB values (i.e., 1/2 LSB, 3/2 LSBs,
5/2 LSBs . . . FS –3/2 LSBs). The output coding is straight
binary with 1 LSB = FS/4096 or 2.5 V/4096 = 0.61 mV when
VREF = 2.5 V. The ideal input/output transfer characteristic for
the 0 to VREF range is shown in Figure 5.
The ADC conversion block incorporates a fast, 8-channel,
12-bit, single-supply ADC. This block provides the user with
multichannel mux, track-and-hold, on-chip reference, calibra-
tion features, and ADC. All components in this block are easily
configured via a 3-register SFR interface.
The ADC consists of a conventional successive-approximation
converter based around a capacitor DAC. The converter accepts
an analog input range of 0 V to VREF. A high precision, low drift
and factory calibrated 2.5 V reference is provided on-chip. The
internal reference may be overdriven via the external VREF pin.
OUTPUT
CODE
111...111
111...110
111...101
This external reference can be in the range 2.3 V to AVDD
.
111...100
Single step or continuous conversion modes can be initiated in
software or alternatively by applying a convert signal to an external
pin. Timer 2 can also be configured to generate a repetitive trigger
for ADC conversions. The ADC may be configured to operate
in a DMA mode whereby the ADC block continuously converts
and captures samples to an external RAM space without any
interaction from the MCU core. This automatic capture facility
can extend through a 16 MByte external Data Memory space.
FS
1LSB =
4096
000...011
000...010
000...001
000...000
0V 1LSB
+FS
VOLTAGE INPUT
–1LSB
The ADuC812 is shipped with factory programmed calibration
coefficients that are automatically downloaded to the ADC on
power-up, ensuring optimum ADC performance. The ADC
core contains internal offset and gain calibration registers.
A software calibration routine is provided to allow the user to
overwrite the factory programmed calibration coefficients if
required, thus minimizing the impact of endpoint errors in the
user’s target system.
Figure 5. ADC Transfer Function
Typical Operation
Once configured via the ADCCON 1–3 SFRs (shown on the
following page), the ADC will convert the analog input and
provide an ADC 12-bit result word in the ADCDATAH/L SFRs.
The top four bits of the ADCDATAH SFR will be written
with the channel selection bits to identify the channel result.
The format of the ADC 12-bit result word is shown in Figure 6.
A voltage output from an on-chip band gap reference propor-
tional to absolute temperature can also be routed through the
front end ADC multiplexer (effectively a ninth ADC channel
input) facilitating a temperature sensor implementation.
ADCDATAH SFR
CH–ID
TOP 4 BITS
HIGH 4 BITS OF
ADC RESULT WORD
ADCDATAL SFR
LOW 8 BITS OF THE
ADC RESULT WORD
Figure 6. ADC Result Format
–12–
REV. E
ADuC812
ADCCON1—(ADC Control SFR #1)
The ADCCON1 register controls conversion and acquisition times, hardware conversion modes and power-down modes as
detailed below.
SFR Address
SFR Power-On Default Value
EFH
20H
MD1
MD0
CK1
CK0
AQ1
AQ0
T2C
EXC
Table III. ADCCON1 SFR Bit Designations
Bit
Name
Description
ADCCON1.7 MD1
ADCCON1.6 MD0
The mode bits (MD1, MD0) select the active operating mode of the ADC as follows:
MD1 MD0 Active Mode
0
0
1
1
0
1
0
1
ADC powered down
ADC normal mode
ADC powered down if not executing a conversion cycle
ADC standby if not executing a conversion cycle
Note: In power-down mode the ADC VREF circuits are maintained on, whereas all ADC peripherals are
powered down, thus minimizing current consumption.
ADCCON1.5 CK1
ADCCON1.4 CK0
The ADC clock divide bits (CK1, CK0) select the divide ratio for the master clock used to generate the
ADC clock. A typical ADC conversion will require 17 ADC clocks. The divider ratio is selected
as follows:
CK1 CK0 MCLK Divider
0
0
1
1
0
1
0
1
1
2
4
8
ADCCON1.3 AQ1
ADCCON1.2 AQ0
The ADC acquisition select bits (AQ1, AQ0) select the time provided for the input track-and-hold
amplifier to acquire the input signal, and are selected as follows:
AQ1 AQ0 #ADC Clks
0
0
1
1
0
1
0
1
1
2
4
8
ADCCON1.1 T2C
ADCCON1.0 EXC
The Timer 2 conversion bit (T2C) is set by the user to enable the Timer 2 overflow bit be used as
the ADC convert start trigger input. ADC conversions are initiated on the second Timer 2 overflow.
The external trigger enable bit (EXC) is set by the user to allow the external CONVST pin to be
used as the active low convert start input. This input should be an active low pulse (minimum
pulsewidth >100 ns) at the required sample rate.
REV. E
–13–
ADuC812
ADCCON2—(ADC Control SFR #2)
The ADCCON2 register controls ADC channel selection and conversion modes as detailed below.
SFR Address
SFR Power-On Default Value
D8H
00H
ADCI
DMA
CCONV
SCONV
CS3
CS2
CS1
CS0
Table IV. ADCCON2 SFR Bit Designations
L
ocation
Name
Description
ADCCON2.7 ADCI
The ADC interrupt bit (ADCI) is set by hardware at the end of a single ADC conversion cycle or at the
end of a DMA block conversion. ADCI is cleared by hardware when the PC vectors to the ADC Interrupt
Service Routine.
ADCCON2.6 DMA
The DMA mode enable bit (DMA) is set by the user to enable a preconfigured ADC DMA mode operation.
A more detailed description of this mode is given in the ADC DMA Mode section.
ADCCON2.5 CCONV
The continuous conversion bit (CCONV) is set by the user to initiate the ADC into a continuous mode
of conversion. In this mode, the ADC starts converting based on the timing and channel configuration
already set up in the ADCCON SFRs; the ADC automatically starts another conversion once a previous
conversion has completed.
ADCCON2.4 SCONV
The single conversion bit (SCONV) is set to initiate a single conversion cycle. The SCONV bit is
automatically reset to “0” on completion of the single conversion cycle.
ADCCON2.3 CS3
ADCCON2.2 CS2
ADCCON2.1 CS1
ADCCON2.0 CS0
The channel selection bits (CS3–0) allow the user to program the ADC channel selection under
software control. When a conversion is initiated, the channel converted will be the one pointed to by
these channel selection bits. In DMA mode, the channel selection is derived from the channel ID
written to the external memory.
CS3 CS2 CS1 CS0 CH#
0
0
0
0
0
0
0
0
1
1
0
0
0
0
1
1
1
1
0
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
2
3
4
5
6
7
Temp Sensor
DMA STOP
All other combinations reserved.
ADCCON3—(ADC Control SFR #3)
The ADCCON3 register gives user software an indication of ADC busy status.
SFR Address
SFR Power-On Default Value
F5H
00H
BUSY
RSVD
RSVD
RSVD
RSVD
RSVD
RSVD
RSVD
Table V. ADCCON3 SFR Bit Designations
Bit Location Bit Status Description
ADCCON3.7 BUSY
The ADC busy status bit (BUSY) is a read-only status bit that is set during a valid ADC conversion
or calibration cycle. BUSY is automatically cleared by the core at the end of conversion or calibration.
ADCCON3.6 RSVD
ADCCON3.5 RSVD
ADCCON3.4 RSVD
ADCCON3.3 RSVD
ADCCON3.2 RSVD
ADCCON3.1 RSVD
ADCCON3.0 RSVD
ADCCON3.0–3.6 are reserved (RSVD) for internal use. These bits will read as “0” and should only
be written as “0” by user software.
–14–
REV. E
ADuC812
Driving the ADC
ADuC812
The ADC incorporates a successive approximation (SAR) archi-
tecture involving a charge-sampled input stage. Figure 7 shows
the equivalent circuit of the analog input section. Each ADC
conversion is divided into two distinct phases as defined by the
position of the switches in Figure 7. During the sampling phase
(with SW1 and SW2 in the “track” position), a charge propor-
tional to the voltage on the analog input is developed across the
input sampling capacitor. During the conversion phase (with
both switches in the “hold” position), the capacitor DAC is
adjusted via internal SAR logic until the voltage on node A is zero,
indicating that the sampled charge on the input capacitor is
balanced out by the charge being output by the capacitor DAC.
The digital value finally contained in the SAR is then latched
out as the result of the ADC conversion. Control of the SAR,
and timing of acquisition and sampling modes, is handled
automatically by built-in ADC control logic. Acquisition and
conversion times are also fully configurable under user control.
51ꢃ
1
ADC0
0.01ꢄF
Figure 8. Buffering Analog Inputs
sampling capacitor can draw its charge. Since the 0.01 µF capacitor
in Figure 8 is more than 4096 times the size of the 2 pF sampling
capacitor, its voltage will not change by more than one count
(1/4096) of the 12-bit transfer function when the 2 pF charge
from a previous channel is dumped onto it. A larger capacitor
can be used if desired, but not a larger resistor (for reasons
described below).
The Schottky diodes in Figure 8 may be necessary to limit the
voltage applied to the analog input pin as per the Absolute Maxi-
mum Ratings. They are not necessary if the op amp is powered
from the same supply as the ADuC812 since in that case, the
op amp is unable to generate voltages above VDD or below ground.
An op amp is necessary unless the signal source is very low imped-
ance to begin with. DC leakage currents at the ADuC812’s analog
inputs can cause measurable dc errors with external source imped-
ances of as little as 100 Ω. To ensure accurate ADC operation,
keep the total source impedance at each analog input less than
61 Ω. The table below illustrates examples of how source
impedance can affect dc accuracy.
ADC0
TEMPERATURE
SENSOR
ADuC812
ADC7
200ꢃ
Source
Error from 1 ꢄA
Error from 10 ꢄA
TRACK
Impedance
Leakage Current
Leakage Current
SW1
2pF
CAPACITOR
DAC
61 Ω
610 Ω
61 µV = 0.1 LSB
610 µV = 1 LSB
610 µV = 1 LSB
61 mV = 10 LSB
HOLD
NODE A
SW2
Although Figure 8 shows the op amp operating at a gain of 1,
you can configure it for any gain needed. Also, you can use an
instrumentation amplifier in its place to condition differential
signals. Use any modern amplifier that is capable of delivering
the signal (0 to VREF) with minimal saturation. Some single-supply,
rail-to-rail op amps that are useful for this purpose include, but
are not limited to, the ones given in Table VI. Check Analog
Devices literature (CD ROM data book, and so on) for details
about these and other op amps and instrumentation amps.
TRACK
HOLD
COMPARATOR
AGND
Figure 7. Internal ADC Structure
Note that whenever a new input channel is selected, a residual
charge from the 2 pF sampling capacitor places a transient on
the newly selected input. The signal source must be capable of
recovering from this transient before the sampling switches click
into “hold” mode. Delays can be inserted in software (between
channel selection and conversion request) to account for input
stage settling, but a hardware solution will alleviate this burden
from the software design task and will ultimately result in a
cleaner system implementation. One hardware solution would
be to choose a very fast settling op amp to drive each analog
input. Such an op amp would need to settle fully from a small
signal transient in less than 300 ns to guarantee adequate settling
under all software configurations. A better solution, recommended
for use with any amplifier, is shown in Figure 8.
Table VI. Some Single-Supply Op Amps
Op Amp Model
Characteristics
OP181/OP281/OP481
OP191/OP291/OP491
OP196/OP296/OP496
OP183/OP283
OP162/OP262/OP462
AD820/AD822/AD824
AD823
Micropower
I/O Good up to VDD, Low Cost
I/O to VDD, Micropower, Low Cost
High Gain-Bandwidth Product
High GBP, Micro Package
FET Input, Low Cost
FET Input, High GBP
Keep in mind that the ADC’s transfer function is 0 V to VREF
,
Though at first glance the circuit in Figure 8 may look like a
simple antialiasing filter, it actually serves no such purpose since
its corner frequency is well above the Nyquist frequency, even at
a 200 kHz sample rate. Though the R/C does help to reject some
incoming high frequency noise, its primary function is to ensure
that the transient demands of the ADC input stage are met. It
does so by providing a capacitive bank from which the 2 pF
and any signal range lost to amplifier saturation near ground will
impact dynamic range. Though the op amps in Table VI are
capable of delivering output signals very closely approaching
ground, no amplifier can deliver signals all the way to ground when
powered by a single supply. Therefore, if a negative supply is
available, consider using it to power the front end amplifiers.
REV. E
–15–
ADuC812
However, be sure to include the Schottky diodes shown in
Figure 8 (or at least the lower of the two diodes) to protect the
analog input from undervoltage conditions. To summarize this
section, use the circuit of Figure 8 to drive the analog input pins
of the ADuC812.
ADuC812
V
DD
2.5V
51ꢃ
BAND GAP
EXTERNAL
VOLTAGE
REFERENCE
REFERENCE
BUFFER
V
REF
Voltage Reference Connections
The on-chip 2.5 V band gap voltage reference can be used as
the reference source for the ADC and DACs. To ensure the
accuracy of the voltage reference, decouple both the VREF pin and
the CREF pin to ground with 0.1 µF ceramic chip capacitors as
shown in Figure 9.
0.1ꢄF
C
REF
0.1ꢄF
Figure 10. Using an External Voltage Reference
Configuring the ADC
ADuC812
2.5V
BAND GAP
REFERENCE
51ꢃ
The three SFRs (ADCCON1, ADCCON2, ADCCON3) con-
figure the ADC. In nearly all cases, an acquisition time of one
ADC clock (ADCCON1.2 = 0, ADCCON1.3 = 0) will provide
plenty of time for the ADuC812 to acquire its signal before
switching the internal track-and-hold amplifier into hold mode.
The only exception would be a high source impedance analog
input, but these should be buffered first anyway since source
impedances of greater than 610 Ω can cause dc errors as well.
BUFFER
BUFFER
V
REF
0.1ꢄF
C
REF
0.1ꢄF
The ADuC812’s successive approximation ADC is driven by a
divided down version of the master clock. To ensure adequate
ADC operation, this ADC clock must be between 400 kHz and
4 MHz, and optimum performance is obtained with ADC clock
between 400 kHz and 3 MHz. Frequencies within this range can
be achieved with master clock frequencies from 400 kHz to well
above 16 MHz with the four ADC clock divide ratios to choose
from. For example, with a 12 MHz master clock, set the ADC
clock divide ratio to 4 (i.e., ADCCLK = MCLK/4 = 3 MHz) by
setting the appropriate bits in ADCCON1 (ADCCON1.5 = 1,
ADCCON1.4 = 0).
Figure 9. Decoupling VREF and CREF
The internal voltage reference can also be tapped directly from
the VREF pin, if desired, to drive external circuitry. However, a
buffer must be used to ensure that no current is drawn from the
VREF pin itself. The voltage on the CREF pin is that of an internal
node within the buffer block, and its voltage is critical to ADC
and DAC accuracy. Do not connect anything to this pin except
the capacitor, and be sure to keep trace-lengths short on the
CREF capacitor, decoupling the node straight to the underlying
ground plane.
The total ADC conversion time is 15 ADC clocks, plus one
ADC clock for synchronization, plus the selected acquisition
time (1, 2, 3, or 4 ADC clocks). For the example above, with a
one clock acquisition time, total conversion time is 17 ADC clocks
(or 5.67 µs for a 3 MHz ADC clock).
The ADuC812 powers up with its internal voltage reference in the
“off” state. The voltage reference turns on automatically whenever
the ADC or either DAC gets enabled in software. Once enabled,
the voltage reference requires approximately 65 ms to power up
and settle to its specified value. Be sure that your software allows
this time to elapse before initiating any conversions. If an external
voltage reference is preferred, connect it to the VREF pin as shown
in Figure 10 to overdrive the internal reference.
In continuous conversion mode, a new conversion begins each
time the previous one finishes. The sample rate is the inverse of the
total conversion time described above. In the example above, the
continuous conversion mode sample rate would be 176.5 kHz.
To ensure accurate ADC operation, the voltage applied to VREF
must be between 2.3 V and AVDD. In situations where analog
input signals are proportional to the power supply (such as some
strain gage applications), it may be desirable to connect the
VREF pin directly to AVDD. In such a configuration, the user
must also connect the CREF pin directly to AVDD to circumvent
internal buffer headroom limitations. This allows the ADC
input transfer function to span the full range of 0 V to AVDD
accurately.
ADC DMA Mode
The on-chip ADC has been designed to run at a maximum
conversion speed of 5 µs (200 kHz sampling rate). When con-
verting at this rate, the ADuC812 MicroConverter has 5 µs to
read the ADC result and store the result in memory for further
postprocessing, otherwise the next ADC sample could be lost.
In an interrupt driven routine, the MicroConverter would also
have to jump to the ADC Interrupt Service routine, which will
also increase the time required to store the ADC results. In
applications where the ADuC812 cannot sustain the interrupt
rate, an ADC DMA mode is provided.
Operation of the ADC or DACs with a reference voltage below
2.3 V, however, may incur loss of accuracy resulting in missing
codes or nonmonotonicity. For that reason, do not use a reference
voltage less than 2.3 V.
To enable DMA mode, Bit 6 in ADCCON2 (DMA) must be set.
This allows the ADC results to be written directly to a 16 MByte
external static memory SRAM (mapped into data memory space)
–16–
REV. E
ADuC812
without any interaction from the ADuC812 core. This mode
allows the ADuC812 to capture a contiguous sample stream at
full ADC update rates (200 kHz).
STOP COMMAND
1
0
0
1
0
0
1
0
0
0
1
0
1
1
1
1
1
1
0
1
0
00000AH
NO CONVERSION
RESULT WRITTEN HERE
CONVERSION RESULT
FOR ADC CH#3
DMA Mode Configuration Example
To set the ADuC812 into DMA mode, a number of steps must
be followed.
CONVERSION RESULT
FOR TEMP SENSOR
0
1. The ADC must be powered down by setting MD1 and MD0
to 0 in ADCCON1.
CONVERSION RESULT
FOR ADC CH#5
0
CONVERSION RESULT
FOR ADC CH#2
2. The DMA Address pointer must be set to the start address of
where the ADC results are to be written. This is done by
writing to the DMA mode Address Pointers DMAL, DMAH,
and DMAP. DMAL must be written to first, followed by
DMAH, and then DMAP.
000000H
1
Figure 12. Typical External Memory Configuration Post
ADC DMA Operation
The DMA logic operates from the ADC clock and uses pipelining
to perform the ADC conversions and access the external memory
at the same time. The time it takes to perform one ADC conver-
sion is called a DMA cycle. The actions performed by the logic
during a typical DMA cycle are shown in Figure 13.
3. The external memory must be preconfigured. This consists of
writing the required ADC channel IDs into the top four bits of
every second memory location in the external SRAM, starting
at the first address specified by the DMA address pointer. As the
ADC DMA mode operates independently of the ADuC812
core, it is necessary to provide it with a stop command. This is
done by duplicating the last channel ID to be converted, fol-
lowed by “1111” into the next channel selection field. Figure 11
shows a typical preconfiguration of external memory.
CONVERT CHANNEL READ DURING PREVIOUS DMA CYCLE
WRITE ADC RESULT
CONVERTED DURING
PREVIOUS DMA CYCLE
READ CHANNEL ID
TO BE CONVERTED DURING
NEXT DMA CYCLE
STOP COMMAND
DMA CYCLE
1
0
0
1
0
0
1
0
0
0
1
0
1
1
1
1
1
1
0
1
0
00000AH
REPEAT LAST CHANNEL
FOR A VALID STOP
CONDITION
Figure 13. DMA Cycle
From the previous diagram, it can be seen that during one DMA
cycle the following actions are performed by the DMA logic.
CONVERT ADC CH#3
CONVERT TEMP SENSOR
CONVERT ADC CH#5
1. An ADC conversion is performed on the channel whose ID
was read during the previous cycle.
0
0
2. The 12-bit result and the channel ID of the conversion per-
formed in the previous cycle are written to the external memory.
000000H
1
CONVERT ADC CH#2
3. The ID of the next channel to be converted is read from
external memory.
Figure 11. Typical DMA External Memory Preconfiguration
4. The DMA is initiated by writing to the ADC SFRs in the
following sequence.
For the previous example, the complete flow of events is shown
in Figure 13. Because the DMA logic uses pipelining, it takes
three cycles before the first correct result is written out.
a. ADCCON2 is written to enable the DMA mode, i.e.,
MOV ADCCON2, #40H; DMA mode enabled.
Micro Operation during ADC DMA Mode
b. ADCCON1 is written to configure the conversion time and
power-up of the ADC. It can also enable Timer 2 driven
conversions or External Triggered conversions if required.
During ADC DMA mode, the MicroConverter core is free to
continue code execution, including general housekeeping and
communication tasks. However, it should be noted that MCU core
accesses to Ports 0 and 2 (which are being used by the DMA
controller) are gated OFF during ADC DMA mode of operation.
This means that even though the instruction that accesses the
external Ports 0 or 2 will appear to execute, no data will be seen
at these external ports as a result.
c. ADC conversions are initiated by starting single/continuous
conversions, starting Timer 2 running for Timer 2 conver-
sions, or by receiving an external trigger.
When the DMA conversions are completed, the ADC interrupt
bit ADCI is set by hardware and the external SRAM contains the
new ADC conversion results as shown in Figure 12. It should be
noted that no result is written to the last two memory locations.
The MicroConverter core can be configured with an interrupt
to be triggered by the DMA controller when it has finished
filling the requested block of RAM with ADC results, allowing
the service routine for this interrupt to postprocess data without
any real-time timing constraints.
When the DMA mode logic is active, it is responsible for storing
the ADC results away from both the user and ADuC812 core
logic. As it writes the results of the ADC conversions to external
memory, it takes over the external memory interface from the core.
Thus, any core instructions that access the external memory
while DMA mode is enabled will not gain access to it. The core
will execute the instructions and they will take the same time to
execute, but they will not gain access to the external memory.
Offset and Gain Calibration Coefficients
The ADuC812 has two ADC calibration coefficients, one for offset
calibration and one for gain calibration. Both the offset and gain
calibration coefficients are 14-bit words, located in the Special
Function Register (SFR) area. The offset calibration coefficient
is divided into ADCOFSH (six bits) and ADCOFSL (eight bits),
REV. E
–17–
ADuC812
and the gain calibration coefficient is divided into ADCGAINH
(six bits) and ADCGAINL (eight bits). The offset calibration
coefficient compensates for dc offset errors in both the ADC and
the input signal.
EPROM
EEPROM
TECHNOLOGY
TECHNOLOGY
IN-CIRCUIT
REPROGRAMMABLE
SPACE EFFICIENT/
DENSITY
Increasing the offset coefficient compensates for positive offset,
and effectively pushes the ADC transfer function DOWN. De-
creasing the offset coefficient compensates for negative offset,
and effectively pushes the ADC transfer function UP. The
maximum offset that can be compensated is typically 5% of
VREF, which equates to typically 125 mV with a 2.5 V reference.
FLASH/EE MEMORY
TECHNOLOGY
Figure 14. Flash Memory Development
Overall, Flash/EE memory represents a step closer to the ideal
memory device that includes nonvolatility, in-circuit programma-
bility, high density, and low cost. Incorporated in the ADuC812,
Flash/EE memory technology allows the user to update program
code space in-circuit without replacing one-time programmable
(OTP) devices at remote operating nodes.
Similarly, the gain calibration coefficient compensates for dc gain
errors in both the ADC and the input signal.
Increasing the gain coefficient compensates for a smaller analog
input signal range and scales the ADC transfer function UP,
effectively increasing the slope of the transfer function. Decreasing
the gain coefficient compensates for a larger analog input signal
range and scales the ADC transfer function DOWN, effectively
decreasing the slope of the transfer function. The maximum analog
input signal range for which the gain coefficient can compensate
Flash/EE Memory and the ADuC812
The ADuC812 provides two arrays of Flash/EE memory for user
applications. 8K bytes of Flash/EE program space are provided
on-chip to facilitate code execution without any external discrete
ROM device requirements. The program memory can be pro-
grammed using conventional third party memory programmers.
This array can also be programmed in-circuit, using the serial
download mode provided.
is 1.025 ϫ VREF, and the minimum input range is 0.975 ϫ VREF
,
which equates to 2.5% of the reference voltage.
Calibration
Each ADuC812 is calibrated in the factory prior to shipping, and
A 640 byte Flash/EE data memory space is also provided on-chip
as a general-purpose nonvolatile scratchpad area. User access to
this area is via a group of six SFRs.
the offset and gain calibration coefficients are stored in a hidden
area of FLASH/EE memory. Each time the ADuC812 powers up,
an internal power-on configuration routine copies these coefficients
into the offset and gain calibration registers in the SFR area.
ADuC812 Flash/EE Memory Reliability
The Flash/EE program and data memory arrays on the ADuC812
are fully qualified for two key Flash/EE memory characteristics:
Flash/EE Memory Cycling Endurance and Flash/EE Memory
Data Retention.
The MicroConverter ADC accuracy may vary from system
to system due to board layout, grounding, clock speed, and so
on. To get the best ADC accuracy in your system, perform
the software calibration routine described in Application Note
uC005, available from the MicroConverter homepage at
www.analog.com/microconverter.
Endurance quantifies the ability of the Flash/EE memory to be
cycled through many program, read, and erase cycles. In real
terms, a single endurance cycle is composed of four independent
sequential events:
NONVOLATILE FLASH MEMORY
Flash Memory Overview
a. Initial Page Erase Sequence
b. Read/Verify Sequence
c. Byte Program Sequence
d. Second Read/Verify Sequence
The ADuC812 incorporates Flash memory technology on-chip
to provide the user with a nonvolatile, in-circuit reprogrammable
code and data memory space.
Flash/EE memory is a relatively new type of nonvolatile memory
technology based on a single transistor cell architecture.
In reliability qualification, every byte in the program and data
Flash/EE memory is cycled from 00H to FFH until the first fail is
recorded, signifying the endurance limit of the on-chip Flash/EE
memory.
This technology is basically an outgrowth of EPROM technology
and was developed in the late 1980s. Flash/EE memory takes the
flexible in-circuit reprogrammable features of EEPROM and
combines them with the space efficient/density features of EPROM
(see Figure 14).
As indicated in the Specification tables, the ADuC812 Flash/EE
Memory Endurance qualification has been carried out in accor-
dance with JEDEC Specification A117 over the industrial
temperature ranges of –40°C, +25°C, and +85°C. The results
allow the specification of a minimum endurance figure over supply
and temperature of 10,000 cycles, with an endurance figure of
50,000 cycles being typical of operation at 25°C.
Because Flash/EE technology is based on a single transistor cell
architecture, a Flash memory array, like EPROM, can be imple-
mented to achieve the space efficiencies or memory densities
required by a given design.
Retention quantifies the ability of the Flash/EE memory to retain
its programmed data over time. Again, the ADuC812 has been
qualified in accordance with the formal JEDEC Retention Lifetime
Like EEPROM, Flash memory can be programmed in-system
at a byte level, although it must first be erased in page blocks.
Thus, Flash memory is often and more correctly referred to as
Flash/EE memory.
Specification (A117) at a specific junction temperature (T = 55°C).
J
As part of this qualification procedure, the Flash/EE memory is
cycled to its specified endurance limit described above, before data
retention is characterized. This means that the Flash/EE memory
is guaranteed to retain its data for its full specified retention
lifetime every time the Flash/EE memory is reprogrammed.
–18–
REV. E
ADuC812
Using the Flash/EE Program Memory
U
sing the Flash/EE Data Memory
This 8K byte Flash/EE program memory array is mapped
into the lower 8K bytes of the 64K bytes program space address-
able by the ADuC812 and will be used to hold user code in
typical applications.
The user Flash/EE data memory array consists of 640 bytes that
are configured into 160 (Page 00H to Page 9FH) 4-byte pages,
as shown in Figure 16.
9FH
BYTE 1
BYTE 2
BYTE 3
BYTE 4
The program memory array can be programmed in one of
two modes:
Serial Downloading (In-Circuit Programming)
As part of its embedded download/debug kernel, the ADuC812
facilitates serial code download via the standard UART serial port.
Serial download mode is automatically entered on power-up if the
external pin PSEN is pulled low through an external resistor as
shown in Figure 15. Once in this mode, the user can download code
to the program memory array while the device is sited in its target
application hardware. A PC serial download executable is provided
as part of the ADuC812 QuickStart development system.
00H
BYTE 1
BYTE 2
BYTE 3
BYTE 4
Figure 16. User Flash/EE Memory Configuration
As with other ADuC812 user peripheral circuits, the interface to
this memory space is via a group of registers mapped in the SFR
space. A group of four data registers (EDATA1–4) is used to hold
the 4-byte page being accessed. EADRL is used to hold the 8-bit
address of the page being accessed. Finally, ECON is an
The Serial Download protocol is detailed in a MicroConverter
Applications Note uC004, available from the ADI MicroConverter
website at www.analog.com/micronverter.
8-bit control register that may be written with one of five Flash/EE
memory access commands to trigger various read, write, erase,
and verify functions. These register can be summarized as follows:
ECON:
SFR Address
Function
B9H
Controls access to 640 bytes
Flash/EE data space.
00H
Default
EADRL:
SFR Address
Function
C6H
Holds the Flash/EE data
page address. 0H through 9FH
00H
Default
EDATA1–4:
SFR Address
Function
BCH to BFH, respectively
Holds the Flash/EE data
memory page write or page
read data bytes.
PULL PSEN LOW DURING RESET TO
CONFIGURE THE ADuC812 FOR
SERIAL DOWNLOAD MODE
ADuC812
Default
EDATA1–4➝00H
PSEN
1kꢃ
A block diagram of the SFR registered interface to the data
Flash/EE memory array is shown in Figure 17.
Figure 15. Flash/EE Memory Serial Download Mode
Programming
FUNCTION:
HOLDS THE 8-BIT PAGE
ADDRESS POINTER
FUNCTION:
HOLDS THE 4-BYTE
PAGE WORD
Parallel Programming
9FH
BYTE 2
BYTE 4
BYTE 3
BYTE 1
The parallel programming mode is fully compatible with
conventional third party Flash or EEPROM device programmers.
In this mode, Ports P0, P1, and P2 operate as the external data
and address bus interface, ALE operates as the Write Enable
strobe, and Port P3 is used as a general configuration port that
configures the device for various program and erase operations
during parallel programming.
EADRL
EDATA1 (BYTE 1)
EDATA2 (BYTE 2)
EDATA3 (BYTE 3)
EDATA4 (BYTE 4)
00H
BYTE 1 BYTE 2 BYTE 3 BYTE 4
ECON COMMAND
INTERPRETER LOGIC
The high voltage (12 V) supply required for Flash programming
is generated using on-chip charge pumps to supply the high
voltage program lines.
FUNCTION:
INTERPRETS THE FLASH
COMMAND WORD
FUNCTION:
HOLDS COMMAND WORD
ECON
The complete parallel programming specification is available on the
MicroConverter homepage at www.analog.com/microconverter.
Figure 17. User Flash/EE Memory Control and
Configuration
REV. E
–19–
ADuC812
ECON—Flash/EE Memory Control SFR
Using the Flash/EE Memory Interface
This SFR acts as a command interpreter and may be written
with one of five command modes to enable various read, pro-
gram, and erase cycles as detailed in Table VII.
As with all Flash/EE memory architectures, the array can be pro-
grammed in system at a byte level, although it must be erased
first, the erasure being performed in page blocks (4-byte pages
in this case).
Table VII. ECON—Flash/EE Memory Control Register
Command Modes
A typical access to the Flash/EE array will involve setting up the
page address to be accessed in the EADRL SFR, configuring the
EDATA1–4 with data to be programmed to the array (the
EDATA SFRs will not be written for read accesses), and finally
writing the ECON command word that initiates one of the six
modes shown in Table VII. It should be noted that a given
mode of operation is initiated as soon as the command word is
written to the ECON SFR. The core microcontroller operation
on the ADuC812 is idled until the requested Program/Read or
Erase mode is completed.
Command Byte Command Mode
01H
READ COMMAND
Results in four bytes being read into
EDATA1–4 from memory page address
contained in EADRL.
02H
PROGRAM COMMAND
Results in four bytes (EDATA1–4) being
written to memory page address in EADRL.
This write command assumes the designated
“write” page has been pre-erased.
RESERVED FOR INTERNAL USE
03H should not be written to the
ECON SFR.
In practice, this means that even though the Flash/EE memory
mode of operation is typically initiated with a two-machine cycle
MOV instruction (to write to the ECON SFR), the next instruction
will not be executed until the Flash/EE operation is complete
(250 µs or 20 ms later). This means that the core will not respond
to Interrupt requests until the Flash/EE operation is complete,
although the core peripheral functions like Counter/Timers will
continue to count and time as configured throughout this pseudo-
idle period.
03H
04H
VERIFY COMMAND
Allows the user to verify if data in EDATA1–4
is contained in page address designated by
EADRL.
Erase-All
A subsequent read of the ECON SFR will
result in a zero being read if the verification
is valid; a nonzero value will be read to
indicate an invalid verification.
ERASE COMMAND
Results in an erase of the 4-byte page
designated in EADRL.
Although the 640-byte user Flash/EE array is shipped from the
factory pre-erased, i.e., byte locations set to FFH, it is nonetheless
good programming practice to include an erase-all routine as
part of any configuration/setup code running on the ADuC812.
An ERASE-ALL command consists of writing 06H to the
ECON SFR, which initiates an erase of all 640 byte locations in
the Flash/EE array. This command coded in 8051 assembly
would appear as:
05H
06H
ERASE-ALL COMMAND
Results in erase of the full Flash/EE data
memory 160-page (640 bytes) array.
MOV ECON, #06H
; Erase all Command
; 20 ms Duration
07H to FFH
RESERVED COMMANDS
Commands reserved for future use.
Program a Byte
In general terms, a byte in the Flash/EE array can only be pro-
grammed if it has previously been erased. To be more specific, a
byte can only be programmed if it already holds the value FFH.
Because of the Flash/EE architecture, this erasure must happen
at a page level; therefore, a minimum of four bytes (1 page) will
be erased when an erase command is initiated. A more specific
example of the Program-Byte process is shown below. In this
example, the user writes F3H into the second byte on Page 03H
of the Flash/EE data memory space while preserving the other
three bytes already in this page. As the user is only required to
modify one of the page bytes, the full page must be first read so that
this page can then be erased without the existing data being lost.
This example, coded in 8051 assembly, would appear as:
Flash/EE Memory Timing
The typical program/erase times for the Flash/EE data
memory are:
Erase Full Array (640 Bytes) – 20 ms
Erase Single Page (4 Bytes) – 20 ms
Program Page (4 Bytes)
Read Page (4 Bytes)
– 250 µs
– Within Single Instruction Cycle
Flash/EE erase and program timing is derived from the master
clock. When using a master clock frequency of 11.0592 MHz, it
is not necessary to write to the ETIM registers at all. However,
when operating at other master clock frequencies (fCLK), you
must change the values of ETIM1 and ETIM2 to avoid degrad-
ing data Flash/EE endurance and retention. ETIM1 and ETIM2
form a 16-bit word, ETIM2 being the high byte and ETIM1 the
low byte. The value of this 16-bit word must be set as follows to
ensure optimum data Flash/EE endurance and retention.
MOV EADRL, #03H
MOV ECON, #01H
; Set Page Address Pointer
; Read Page
MOV EDATA2, #0F3H ; Write New Byte
MOV ECON, #05H
MOV ECON, #02H
; Erase Page
; Write Page (Program
Flash/EE)
ETIM2, ETIM1 = 100 µs × fCLK
ETIM3 should always remain at its default value of 201 dec/C9 hex.
–20–
REV. E
ADuC812
USER INTERFACE TO OTHER ON-CHIP ADuC812
PERIPHERALS
The following section gives a brief overview of the various
peripherals also available on-chip. A summary of the SFRs used
to control and configure these peripherals is also given.
of driving 10 kΩ/100 pF. Each has two selectable ranges, 0 V to
VREF (the internal band gap 2.5 V reference) and 0 V to AVDD
Each can operate in 12-bit or 8-bit mode. Both DACs share a
.
control register, DACCON, and four data registers, DAC1H/L,
DAC0H/L. It should be noted that in 12-bit asynchronous mode,
the DAC voltage output will be updated as soon as the DACL
data SFR has been written; therefore, the DAC data registers
should be updated as DACH first, followed by DACL.
DAC
The ADuC812 incorporates two 12-bit voltage output DACs
on-chip. Each has a rail-to-rail voltage output buffer capable
DAC Control
DACCON
SFR Address
Power-On Default Value
Bit Addressable
Register
FDH
04H
No
MODE
RNG1
RNG0
CLR1
CLR0
SYNC
PD1
PD0
Table VIII. DACCON SFR Bit Designations
Bit
Name
Description
7
MODE
RNG1
RNG0
CLR1
CLR0
SYNC
The DAC MODE bit sets the overriding operating mode for both DACs.
Set to “1” = 8-bit mode (Write eight Bits to DACxL SFR).
Set to “0” = 12-bit mode.
6
5
4
3
2
DAC1 Range Select Bit.
Set to “1” = DAC1 range 0–VDD
.
Set to “0” = DAC1 range 0–VREF
DAC0 Range Select Bit.
.
Set to “1” = DAC0 range 0–VDD
Set to “0” = DAC0 range 0–VREF
DAC1 Clear Bit.
.
.
Set to “0” = DAC1 output forced to 0 V.
Set to “1” = DAC1 output normal.
DAC0 Clear Bit.
Set to “0” = DAC1 output forced to 0 V.
Set to “1” = DAC1 output normal.
DAC0/1 Update Synchronization Bit.
When set to “1” the DAC outputs update as soon as DACxL SFRs are written. The user can
simultaneously update both DACs by first updating the DACxL/H SFRs while SYNC is “0.” Both
DACs will then update simultaneously when the SYNC bit is set to “1.”
DAC1 Power-Down Bit.
Set to “1” = Power-on DAC1.
Set to “0” = Power-off DAC1.
1
0
PD1
PD0
DAC0 Power-Down Bit.
Set to “1” = Power-on DAC0.
Set to “0” = Power-off DAC0.
DACxH/L
DAC Data Registers
Function
SFR Address
DAC data registers, written by user to update the DAC output.
DAC0L (DAC0 Data Low Byte)
➝
➝
➝
➝
F9H; DAC1L (DAC1 data low byte)
➝
➝FCH
FBH
DAC0H (DAC0 Data High Byte)
00H
No
FAH; DAC1H(DAC1 data high byte)
All four registers
All four registers
Power-On Default Value
Bit Addressable
The 12-bit DAC data should be written into DACxH/L, right-justified such that DACL contains the lower eight bits, and the lower
nibble of DACH contains the upper four bits.
REV. E
–21–
ADuC812
V
Using the DAC
DD
The on-chip DAC architecture consists of a resistor string DAC
followed by an output buffer amplifier, the functional equivalent
of which is illustrated in Figure 18. Details of the actual DAC
architecture can be found in U.S. Patent Number 5969657
(www.uspto.gov). Features of this architecture include inherent
guaranteed monotonicity and excellent differential linearity.
V
– 50mV
DD
V
– 100mV
DD
AV
DD
ADuC812
100mV
50mV
0mV
R
V
REF
OUTPUT
BUFFER
R
R
8
000 HEX
FFF HEX
Figure 19. Endpoint Nonlinearities Due to Amplifier
Saturation
HIGH-Z
DISABLE
R
R
(FROM MCU)
The endpoint nonlinearities conceptually illustrated in Figure 19
get worse as a function of output loading. Most of the ADuC812’s
data sheet specifications assume a 10 kΩ resistive load to ground
at the DAC output. As the output is forced to source or sink
more current, the nonlinear regions at the top or bottom
(respectively) of Figure 19 become larger. With larger current
demands, this can significantly limit output voltage swing.
Figure 20 and Figure 21 illustrate this behavior. It should be noted
that the upper trace in each of these figures is only valid for an
output range selection of 0-to-AVDD. In 0-to-VREF mode, DAC
loading will not cause high-side voltage drops as long as the
reference voltage remains below the upper trace in the correspond-
ing figure. For example, if AVDD = 3 V and VREF = 2.5 V, the
high-side voltage will not be affected by loads less than 5 mA.
But somewhere around 7 mA the upper curve in Figure 21 drops
below 2.5 V (VREF), indicating that at these higher currents the
Figure 18. Resistor String DAC Functional Equivalent
As illustrated in Figure 18, the reference source for each DAC is
user selectable in software. It can be either AVDD or VREF. In
0-to-AVDD mode, the DAC output transfer function spans from
0 V to the voltage at the AVDD pin. In 0-to-VREF mode, the
DAC output transfer function spans from 0 V to the internal
VREF, or if an external reference is applied, the voltage at the
VREF pin. The DAC output buffer amplifier features a true rail-to-
rail output stage implementation. This means that unloaded, each
output is capable of swinging to within less than 100 mV of both
AVDD and ground. Moreover, the DAC’s linearity specification
(when driving a 10 kΩ resistive load to ground) is guaranteed
through the full transfer function except codes 0 to 48, and, in
0-to-AVDD mode only, codes 3995 to 4095. Linearity degradation
near ground and VDD is caused by saturation of the output
amplifier, and a general representation of its effects (neglecting
offset and gain error) is illustrated in Figure 19. The dotted line
in Figure 19 indicates the ideal transfer function, and the solid
line represents what the transfer function might look like with
endpoint nonlinearities due to saturation of the output amplifier. Note
that Figure 19 represents a transfer function in 0-to-VDD mode
only. In 0-to-VREF mode (with VREF < VDD) the lower nonlinearity
would be similar, but the upper portion of the transfer function
would follow the “ideal” line right to the end (VREF in this case,
not VDD), showing no signs of endpoint linearity errors.
output will not be capable of reaching VREF
.
5
DAC LOADED WITH 0FFF HEX
4
3
2
1
DAC LOADED WITH 0000 HEX
0
0
5
10
15
SOURCE/SINK CURRENT – mA
Figure 20. Source and Sink Current Capability with
VREF = VDD = 5 V
–22–
REV. E
ADuC812
the DAC outputs will remain at ground potential whenever the
DAC is disabled. However, each DAC output will still spike
briefly when power is first applied to the chip, and again when
each DAC is first enabled in software. Typical scope shots of
these spikes are given in Figure 23 and Figure 24, respectively.
3
2
1
0
200ꢄs/DIV
AV – 2V/DIV
DD
0
5
10
15
SOURCE/SINK CURRENT – mA
Figure 21. Source and Sink Current Capability with
REF = VDD = 3 V
V
DAC OUT – 500mV/DIV
To drive significant loads with the DAC outputs, external
buffering may be required, as illustrated in Figure 22.
Figure 23. DAC Output Spike at Chip Power-Up
5
ꢄ
s/DIV, 1V/DIV
ADuC812
9
10
Figure 22. Buffering the DAC Outputs
The DAC output buffer also features a high impedance disable
function. In the chip’s default power-on state, both DACs are
disabled, and their outputs are in a high impedance state (or
“three-state”) where they remain inactive until enabled in software.
This means that if a zero output is desired during power-up or
power-down transient conditions, then a pull-down resistor must
be added to each DAC output. Assuming this resistor is in place,
Figure 24. DAC Output Spike at DAC Enable
REV. E
–23–
ADuC812
WATCHDOG TIMER
user program fails to set the watchdog timer refresh bits (WDR1,
WDR2) within a predetermined amount of time (see PRE2–0
bits in WDCON). The watchdog timer itself is a 16-bit counter.
The watchdog timeout interval can be adjusted via the PRE2–0 bits
in WDCON. Full Control and Status of the watchdog timer function
can be controlled via the watchdog timer control SFR (WDCON).
The purpose of the watchdog timer is to generate a device reset
within a reasonable amount of time if the ADuC812 enters an
erroneous state, possibly due to a programming error. The Watch-
dog function can be disabled by clearing the WDE (Watchdog
Enable) bit in the Watchdog Control (WDCON) SFR. When
enabled, the watchdog circuit will generate a system reset if the
Watchdog Timer
WDCON
Control Register
SFR Address
Power-On Default Value
Bit Addressable
C0H
00H
Yes
PRE2
PRE1
PRE0
—
WDR1
WDR2
WDS
WDE
Table IX. WDCON SFR Bit Designations
Description
Watchdog Timer Prescale Bits.
Bit
Name
7
6
5
PRE2
PRE1
PRE0
PRE2
PRE1
PRE0
Timeout Period (ms)
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
16
32
64
128
256
512
1024
2048
4
3
2
1
—
Not Used.
WDR1
WDR2
WDS
Watchdog Timer Refresh Bits. Set sequentially to refresh the watchdog timer.
Watchdog Status Bit.
Set by the Watchdog Controller to indicate that a watchdog timeout has occurred.
Cleared by writing a “0” or by an external hardware reset. It is not cleared by a watchdog reset.
Watchdog Enable Bit.
0
WDE
Set by user to enable the watchdog and clear its counters.
Example
POWER SUPPLY MONITOR
To set up the watchdog timer for a timeout period of 2048 ms,
the following code would be used:
As its name suggests, the Power Supply Monitor, once enabled,
monitors both supplies (AVDD and DVDD) on the ADuC812. It
will indicate when either power supply drops below one of five
user selectable voltage trip points from 2.63 V to 4.63 V. For
correct operation of the Power Supply Monitor function, AVDD
must be equal to or greater than 2.7 V. The Power Supply
Monitor function is controlled via the PSMCON SFR. If
enabled via the IE2 SFR, the Power Supply Monitor will interrupt
the core using the PSMI bit in the PSMCON SFR. This bit will
not be cleared until the failing power supply has returned
above the trip point for at least 256 ms. This ensures that the
power supply has fully settled before the bit is cleared. This
monitor function allows the user to save working registers to avoid
possible data loss due to the low supply condition, and also ensures
that normal code execution will not resume until a safe supply
level has been well established. The supply monitor is also
protected against spurious glitches triggering the interrupt circuit.
MOV
WDCON,#0E0h ;2.048 second
;timeout period
SETB
WDE
;enable watchdog timer
To prevent the watchdog timer from timing out, the timer
refresh bits need to be set before 2.048 seconds has elapsed.
SETB
SETB
WDR1
WDR2
;refresh watchdog timer..
; ..bits must be set in this
;order
–24–
REV. E
ADuC812
Power Supply Monitor
PSMCON
Control Register
SFR Address
Power-On Default Value
Bit Addressable
DFH
DCH
No
—
CMP
PSMI
TP2
TP1
TP0
PSF
PSMEN
Table X. PSMCON SFR Bit Designations
Bit
Name
Description
7
6
—
CMP
Not Used.
AVDD and DVDD Comparator Bit.
This is a read-only bit and directly reflects the state of the AVDD and DVDD comparators.
Read “1” indicates that both the AVDD and DVDD supplies are above their selected trip points.
Read “0” indicates that either the AVDD or DVDD supply is below its selected trip point.
Power Supply Monitor Interrupt Bit.
5
PSMI
This bit will be set high by the MicroConverter if CMP is low, indicating low analog or digital
supply. The PSMI bit can be used to interrupt the processor. Once CMPD and/or CMP return
(and remain) high, a 256 ms counter is started. When this counter times out, the PSMI interrupt
is cleared. PSMI can also be written by the user. However, if either comparator output is low,
it is not possible for the user to clear PSMI.
4
TP2
VDD Trip Point Selection Bits.
3
2
TP1
TP0
These bits select the AVDD and DVDD trip point voltage as follows:
TP2
TP1
TP0
Selected DVDD Trip Point (V)
0
0
0
0
1
0
0
1
1
0
0
1
0
1
0
4.63
4.37
3.08
2.93
2.63
1
0
PSF
AVDD/DVDD Fault Indicator.
Read “1” indicates that the AVDD supply caused the fault condition.
Read “0” indicates that the DVDD supply caused the fault condition.
Power Supply Monitor Enable Bit.
PSMEN
Set to “1” by the user to enable the Power Supply Monitor Circuit.
Cleared to “0” by the user to disable the Power Supply Monitor Circuit.
Example
SERIAL PERIPHERAL INTERFACE
To configure the PSM for a trip point of 4.37 V, the following
code would be used:
MOV
The ADuC812 integrates a complete hardware Serial Peripheral
Interface (SPI) on-chip. SPI is an industry-standard synchronous
serial interface that allows eight bits of data to be synchronously
transmitted and received simultaneously, i.e., full duplex. It should
be noted that the SPI pins are shared with the I2C interface, and
therefore the user can only enable one or the other interface at
any given time (see SPE in Table XI). The SPI Port can be con-
figured for Master or Slave operation and typically consists of
four pins, namely:
PSMCON,#005h
;enable PSM with
;4.37V threshold
;enable interrupts
;enable PSM
SETB
MOV
EA
IE2,#002h
;interrupt
If the supply voltage falls below this level, the PC would vector
to the ISR.
ORG
CHECK:MOV
0043h
A,PSMCON
;PSM ISR
MISO (Master In, Slave Out Data I/O Pin)
;PSMCON.5 is the
;PSM interrupt
;bit..
;..it is cleared
;only when Vdd
;has remained
;above the trip
;point for 256ms
;or more.
The MISO (master in, slave out) pin is configured as an input
line in master mode and an output line in slave mode. The
MISO line on the master (data in) should be connected to the
MISO line in the slave device (data out). The data is transferred
as byte wide (8-bit) serial data, MSB first.
JB
ACC.5,CHECK
RETI
; return only when "all's well"
REV. E
–25–
ADuC812
MOSI (Master Out, Slave In Pin)
data is transmitted on one edge of the SCLOCK signal and
sampled on the other. It is important therefore that the CPHA
and CPOL are configured the same for the master and slave
devices.
The MOSI (master out, slave in) pin is configured as an output
line in master mode and an input line in slave mode. The
MOSI line on the master (data out) should be connected to the
MOSI line in the slave device (data in). The data is transferred as
byte wide (8-bit) serial data, MSB first.
SS (Slave Select Input Pin)
The Slave Select (SS) input pin is shared with the ADC5 input.
To configure this pin as a digital input, the bit must be cleared,
e.g., CLR P1.5.
SCLOCK (Serial Clock I/O Pin)
The master serial clock (SCLOCK) is used to synchronize the
data being transmitted and received through the MOSI and MISO
data lines. A single data bit is transmitted and received in each
SCLOCK period. Therefore, a byte is transmitted/received after
eight SCLOCK periods. The SCLOCK pin is configured as an
output in master mode and as an input in slave mode. In master
mode, the bit rate, polarity, and phase of the clock are controlled
by the CPOL, CPHA, SPR0, and SPR1 bits in the SPICON SFR
(see Table XI). In slave mode, the SPICON register will have to
be configured with the phase and polarity (CPHA and CPOL) of
the expected input clock. In both master and slave modes, the
This line is active low. Data is only received or transmitted in
slave mode when the SS pin is low, allowing the ADuC812 to
be used in single master, multislave SPI configurations. If
CPHA = 1, then the SS input may be permanently pulled low.
With CPHA = 0, the SS input must be driven low before the
first bit in a byte wide transmission or reception, and return
high again after the last bit in that byte wide transmission or
reception. In SPI Slave mode, the logic level on the external SS
pin can be read via the SPR0 bit in the SPICON SFR. The follow-
ing SFR registers are used to control the SPI interface.
SPI Control
SPICON
SFR Address
Register
F8H
Power-On Default Value
Bit Addressable
OOH
Yes
ISPI
WCOL
SPE
SPIM
CPOL
CPHA
SPR1
SPR0
Table XI. SPICON SFR Bit Designations
Description
Bit
Name
7
ISPI
SPI Interrupt Bit.
Set by MicroConverter at the end of each SPI transfer.
Cleared directly by user code or indirectly by reading the SPIDAT SFR.
Write Collision Error Bit.
Set by MicroConverter if SPIDAT is written to while an SPI transfer is in progress.
Cleared by user code.
6
5
4
3
2
WCOL
SPE
SPI Interface Enable Bit.
Set by user to enable the SPI interface.
Cleared by user to enable I2C interface.
SPIM
SPI Master/Slave Mode Select Bit.
Set by user to enable Master mode operation (SCLOCK is an output).
Cleared by user to enable Slave mode operation (SCLOCK is an input).
Clock Polarity Select Bit.
Set by user if SCLOCK idles high.
Cleared by user if SCLOCK idles low.
CPOL*
CPHA*
Clock Phase Select Bit.
Set by user if leading SCLOCK edge is to transmit data.
Cleared by user if trailing SCLOCK edge is to transmit data.
SPI Bit Rate Select Bits.
1
0
SPR1
SPR0
These bits select the SCLOCK rate (bit rate) in Master mode as follows:
SPR1
SPR0
Selected Bit Rate
fOSC/4
fOSC/8
0
0
1
1
0
1
0
1
fOSC/32
f
OSC/64
In SPI Slave mode, i.e., SPIM = 0, the logic level on the external SS pin can be read
via the SPR0 bit.
*The CPOL and CPHA bits should both contain the same values for master and slave devices.
–26–
REV. E
ADuC812
SPIDAT
SPI Data Register
SPI Interface—Master Mode
Function
The SPIDAT SFR is written by the
user to transmit data over the SPI
interface or read by user code to read
data just received by the SPI interface.
F7H
00H
No
In master mode, the SCLOCK pin is always an output and gener-
ates a burst of eight clocks whenever user code writes to the
SPIDAT register. The SCLOCK bit rate is determined by SPR0
and SPR1 in SPICON. It should also be noted that the SS pin
is not used in master mode. If the ADuC812 needs to assert the
SS pin on an external slave device, a Port digital output pin
should be used.
SFR Address
Power-On Default Value
Bit Addressable
Using the SPI Interface
In master mode a byte transmission or reception is initiated by
a write to SPIDAT. Eight clock periods are generated via the
SCLOCK pin and the SPIDAT byte being transmitted via MOSI.
With each SCLOCK period a data bit is also sampled via
MISO. After eight clocks, the transmitted byte will have been
completely transmitted and the input byte will be waiting in
the input shift register. The ISPI flag will be set automatically
and an interrupt will occur if enabled. The value in the shift
register will be latched into SPIDAT.
Depending on the configuration of the bits in the SPICON SFR
shown in Table XI, the ADuC812 SPI interface will transmit or
receive data in a number of possible modes. Figure 25 shows all
possible ADuC812 SPI configurations and the timing relationships
and synchronization between the signals involved. Also shown in
this figure is the SPI interrupt bit (ISPI) and how it is triggered
at the end of each byte wide communication.
SCLOCK
(CPOL = 1)
SPI Interface—Slave Mode
In slave mode the SCLOCK is an input. The SS pin must also
be driven low externally during the byte communication.
SCLOCK
(CPOL = 0)
Transmission is also initiated by a write to SPIDAT. In slave mode,
a data bit is transmitted via MISO and a data bit is received via
MOSI through each input SCLOCK period. After eight clocks,
the transmitted byte will have been completely transmitted and
the input byte will be waiting in the input shift register. The
ISPI flag will be set automatically and an interrupt will occur
if enabled. The value in the shift register will be latched into
SPIDAT only when the transmission/reception of a byte has been
completed. The end of transmission occurs after the eighth
clock has been received if CPHA = 1, or when SS returns high
if CPHA = 0.
SS
SAMPLE INPUT
DATA OUTPUT
?
MSB BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 LSB
ISPI FLAG
SAMPLE INPUT
DATA OUTPUT
MSB BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 LSB
?
ISPI FLAG
Figure 25. SPI Timing, All Modes
REV. E
–27–
ADuC812
I2C* COMPATIBLE INTERFACE
SDATA
SCLOCK
Serial Data I/O Pin
Serial Clock
The ADuC812 supports a 2-wire serial interface mode that is
I2C compatible. The I2C compatible interface shares its pins with
the on-chip SPI interface and therefore the user can only enable
one or the other interface at any given time (see SPE in Table IX).
An application note describing the operation of this interface as
implemented is available from the MicroConverter website at
www.analog.com/microconverter. This interface can be configured
as a software master or hardware slave, and uses two pins in the
interface.
Three SFRs are used to control the I2C compatible interface.
These are described below:
I2CCON
SFR Address
Power-On Default Value
Bit Addressable
I2C Control Register
E8H
00H
Yes
MDO
MDE
MCO
MDI
I2CM
I2CRS
I2CTX
I2CI
Table XII. I2CCON SFR Bit Designations
Bit
Name
Description
7
MDO
I2C Software Master Data Output Bit (Master Mode Only).
This data bit is used to implement a master I2C transmitter interface in software. Data written to
this bit will be output on the SDATA pin if the data output enable (MDE) bit is set.
I2C Software Master Data Output Enable Bit (Master Mode Only).
Set by the user to enable the SDATA pin as an output (Tx). Cleared by the user to enable SDATA
pin as an input (Rx).
6
5
4
MDE
MCO
MDI
I2C Software Master Data Output Bit (Master Mode Only).
This data bit is used to implement a master I2C transmitter interface in software. Data written to
this bit will be output on the SCLOCK pin.
I2C Software Master Data Input Bit (Master Mode Only).
This data bit is used to implement a master I2C receiver interface in software. Data on the
SDATA pin is latched into this bit on SCLOCK if the Data Output Enable (MDE) = 0.
I2C Master/Slave Mode Bit.
3
2
1
I2CM
Set by user to enable I2C software master mode. Cleared by user to enable I2C hardware slave mode.
I2C Reset Bit (Slave Mode Only).
I2CRS
Set by user to reset the I2C interface. Cleared by user for normal I2C operation.
I2CTX
I2CI
I2C Direction Transfer Bit (Slave Mode Only).
Set by the MicroConverter if the interface is transmitting. Cleared by the MicroConverter if the
interface is receiving.
0
I2C Interrupt Bit (Slave Mode Only).
Set by the MicroConverter after a byte has been transmitted or received. Cleared by user software.
I2CADD
Function
I2C Address Register
I2CDAT
Function
I2C Data Register
Holds the I2C peripheral address for
the part. It may be overwritten by
the user code. Application note uC001
at www.analog.com/microconverter
describes the format of the I2C
standard 7-bit address in detail.
The I2CDAT SFR is written by the
user to transmit data over the I2C
interface or read by user code to read
data just received by the I2C interface.
User software should only access
I2CDAT once per interrupt cycle.
SFR Address
Power-On Default Value 55H
Bit Addressable No
9BH
SFR Address
Power-On Default Value 00H
Bit Addressable No
9AH
*Purchase of licensed I2C components of Analog Devices or one of its sublicensed Associated Companies conveys a license for the purchaser under the Philips
I2C Patent Rights to use these components in an I2C system, provided that the system conforms to the I2C Standard Specification as defined by Philips.
–28–
REV. E
ADuC812
8051 COMPATIBLE ON-CHIP PERIPHERALS
Port 3 is a bidirectional port with internal pull-ups directly
controlled via the P3 SFR (SFR address = B0H). Port 3 pins
that have 1s written to them are pulled high by the internal pull-ups
and, in that state, can be used as inputs. As inputs, Port 3 pins
being pulled externally low will source current because of the internal
pull-ups. Port 3 pins also have various secondary functions
described in Table XIV.
This section gives a brief overview of the various secondary
peripheral circuits that are also available to the user on-chip.
These remaining functions are fully 8051 compatible and are
controlled via standard 8051 SFR bit definitions.
Parallel I/O Ports 0–3
The ADuC812 uses four input/output ports to exchange data with
external devices. In addition to performing general-purpose I/O,
some ports are capable of external memory operations; others
are multiplexed with an alternate function for the peripheral
features on the device. In general, when a peripheral is enabled,
that pin may not be used as a general-purpose I/O pin.
Table XIV. Port 3, Alternate Pin Functions
Pin
Alternate Function
P3.0
RxD (UART Input Pin)
(or Serial Data I/O in Mode 0)
TxD (UART Output Pin)
Port 0 is an 8-bit, open-drain, bidirectional I/O port that is directly
controlled via the P0 SFR (SFR address = 80H). Port 0 pins
that have 1s written to them via the Port 0 SFR will be configured
as open-drain and will therefore float. In that state, Port 0 pins can
be used as high impedance inputs. An external pull-up resistor
will be required on Port 0 outputs to force a valid logic high
level externally. Port 0 is also the multiplexed low order address
and data bus during accesses to external program or data memory.
In this application, it uses strong internal pull-ups when emitting 1s.
P3.1
(or Serial Clock Output in Mode 0)
INT0 (External Interrupt 0)
INT1 (External Interrupt 1)
T0 (Timer/Counter 0 External Input)
T1 (Timer/Counter 1 External Input)
WR (External Data Memory Write Strobe)
RD (External Data Memory Read Strobe)
P3.2
P3.3
P3.4
P3.5
P3.6
P3.7
The alternate functions of P1.0, P1.1, P1.5, and Port 3 pins
can be activated only if the corresponding bit latch in the P1
and P3 SFRs contains a 1. Otherwise, the port pin is stuck at 0.
Port 1 is also an 8-bit port directly controlled via the P1 SFR
(SFR address = 90H). Port 1 is an input only port. Port 1 digital
output capability is not supported on this device. Port 1 pins can
be configured as digital inputs or analog inputs.
Timers/Counters
The ADuC812 has three 16-bit Timer/Counters: Timer 0,
Timer 1, and Timer 2. The Timer/Counter hardware has been
included on-chip to relieve the processor core of the overhead
inherent in implementing timer/counter functionality in software.
Each Timer/Counter consists of two 8-bit registers, THx and
TLx (x = 0, 1, and 2). All three can be configured to operate
either as timers or event counters.
By (power-on) default these pins are configured as analog inputs,
i.e., “1” written in the corresponding Port 1 register bit. To
configure any of these pins as digital inputs, the user should write
a “0” to these port bits to configure the corresponding pin as a
high impedance digital input.
These pins also have various secondary functions described in
Table XIII.
In Timer function, the TLx register is incremented every machine
cycle. Thus, think of it as counting machine cycles. Since a
machine cycle consists of 12 core clock periods, the maximum
count rate is 1/12 of the core clock frequency.
Table XIII. Port 1, Alternate Pin Functions
Pin
Alternate Function
P1.0
P1.1
P1.5
T2 (Timer/Counter 2 External Input)
T2EX (Timer/Counter 2 Capture/Reload Trigger)
SS (Slave Select for the SPI Interface)
In Counter function, the TLx register is incremented by a 1-to-0
transition at its corresponding external input pin, T0, T1, or T2.
In this function, the external input is sampled during S5P2 of
every machine cycle. When the samples show a high in one cycle and
a low in the next cycle, the count is incremented. The new count
value appears in the register during S3P1 of the cycle following the
one in which the transition was detected. Since it takes two machine
cycles (24 core clock periods) to recognize a 1-to-0 transition,
the maximum count rate is 1/24 of the core clock frequency.
There are no restrictions on the duty cycle of the external input
signal, but to ensure that a given level is sampled at least once
before it changes, it must be held for a minimum of one full
machine cycle.
Port 2 is a bidirectional port with internal pull-up resistors directly
controlled via the P2 SFR (SFR address = A0H). Port 2 pins
that have 1s written to them are pulled high by the internal pull-up
resistors and, in that state, can be used as inputs. As inputs, Port
2 pins being pulled externally low will source current because of
the internal pull-up resistors. Port 2 emits the high order
address bytes during fetches from external program memory,
and middle and high order address bytes during accesses to the
24-bit external data memory space.
REV. E
–29–
ADuC812
User configuration and control of all Timer operating modes is achieved via three SFRs:
TMOD, TCON
T2CON
Control and configuration for Timers 0 and 1.
Control and configuration for Timer 2.
Timer/Counter 0 and
1 Mode Register
89H
TMOD
SFR Address
Power-On Default Value 00H
Bit Addressable
No
Gate
C/T
M1
M0
Gate
C/T
M1
M0
Table XV. TMOD SFR Bit Designations
Bit
Name
Description
7
Gate
Timer 1 Gating Control.
Set by software to enable Timer/Counter 1 only while INT1 pin is high and TR1 control bit is set.
Cleared by software to enable Timer 1 whenever TR1 control bit is set.
Timer 1 Timer or Counter Select Bit.
6
C/T
Set by software to select counter operation (input from T1 pin).
Cleared by software to select timer operation (input from internal system clock).
Timer 1 Mode Select Bit 1 (used with M0 Bit).
5
4
M1
M0
Timer 1 Mode Select Bit 0.
M1
0
0
M0
0
1
TH1 operates as an 8-bit timer/counter. TL1 serves as 5-bit prescaler.
16-Bit Timer/Counter. TH1 and TL1 are cascaded; there is no prescaler.
8-Bit Autoreload Timer/Counter. TH1 holds a value that is to be
reloaded into TL1 each time it overflows.
1
0
1
1
Timer/Counter 1 Stopped.
3
2
Gate
C/T
Timer 0 Gating Control.
Set by software to enable Timer/Counter 0 only while INT0 pin is high and TR0 control bit is set.
Cleared by software to enable Timer 0 whenever TR0 control bit is set.
Timer 0 Timer or Counter Select Bit.
Set by software to select counter operation (input from T0 pin).
Cleared by software to select timer operation (input from internal system clock).
Timer 0 Mode Select Bit 1.
1
0
M1
M0
Timer 0 Mode Select Bit 0.
M1
0
0
M0
0
1
TH0 operates as an 8-bit timer/counter. TL0 serves as 5-bit prescaler.
16-Bit Timer/Counter. TH0 and TL0 are cascaded; there is no prescaler.
8-Bit Autoreload Timer/Counter. TH0 holds a value that is to be
reloaded into TL0 each time it overflows.
1
0
1
1
TL0 is an 8-bit timer/counter controlled by the standard timer 0 control
bits. TH0 is an 8-bit timer only, controlled by Timer 1 control bits.
–30–
REV. E
ADuC812
Timer/Counter 0 and
TCON
1 Control Register
SFR Address
Power-On Default Value
Bit Addressable
88H
00H
Yes
TF1
TR1
TF0
TR0
IE1*
IT1*
IE0*
IT0*
*These bits are not used in the control of Timer/Counter 0 and 1, but are used instead in the control and monitoring of the external INT0 and INT1 interrupt pins.
Table XVI. TCON SFR Bit Designations
Bit
Name
Description
7
TF1
Timer 1 Overflow Flag.
Set by hardware on a Timer/Counter 1 overflow.
Cleared by hardware when the Program Counter (PC) vectors to the interrupt service routine.
Timer 1 Run Control Bit.
Set by user to turn on Timer/Counter 1.
Cleared by user to turn off Timer/Counter 1.
Timer 0 Overflow Flag.
Set by hardware on a Timer/Counter 0 overflow.
Cleared by hardware when the PC vectors to the interrupt service routine.
Timer 0 Run Control Bit.
Set by user to turn on Timer/Counter 0.
Cleared by user to turn off Timer/Counter 0.
6
5
4
3
TR1
TF0
TR0
IE1
External Interrupt 1 (INT1) Flag.
Set by hardware by a falling edge or zero level being applied to external interrupt pin INT1,
depending on bit IT1 state.
Cleared by hardware when the when the PC vectors to the interrupt service routine only if the
interrupt was transition-activated. If level-activated, the external requesting source controls the
request flag, rather than the on-chip hardware.
2
1
IT1
IE0
External Interrupt 1 (IE1) Trigger Type.
Set by software to specify edge-sensitive detection (i.e., 1-to-0 transition).
Cleared by software to specify level-sensitive detection (i.e., zero level).
External Interrupt 0 (INT0) Flag.
Set by hardware by a falling edge or zero level being applied to external interrupt pin INT0,
depending on bit IT0 state.
Cleared by hardware when the PC vectors to the interrupt service routine only if the interrupt
was transition activated. If level activated, the external requesting source controls the request flag,
rather than the on-chip hardware.
0
IT0
External Interrupt 0 (IE0) Trigger Type.
Set by software to specify edge-sensitive detection (i.e., 1-to-0 transition).
Cleared by software to specify level-sensitive detection (i.e., zero level).
Timer/Counters 0 and 1 Data Registers
Each timer consists of two 8-bit registers. These can be used as
independent registers or combined to be a single 16-bit register
depending on the timer mode configuration.
TH0 and TL0
Timer 0 high byte and low byte.
SFR Address = 8CH, 8AH, respectively.
TH1 and TL1
Timer 1 high byte and low byte.
SFR Address = 8DH, 8BH, respectively.
REV. E
–31–
ADuC812
TIMER/COUNTERS 0 AND 1 OPERATING MODES
The following paragraphs describe the operating modes for
Timer/Counters 0 and 1. Unless otherwise noted, it should be
assumed that these modes of operation are the same for Timer 0
as for Timer 1.
Mode 2 (8-Bit Timer/Counter with Auto Reload)
Mode 2 configures the timer register as an 8-bit counter (TL0)
with automatic reload, as shown in Figure 28. Overflow from TL0
not only sets TF0, but also reloads TL0 with the contents of TH0,
which is preset by software. The reload leaves TH0 unchanged.
Mode 0 (13-Bit Timer/Counter)
Mode 0 configures an 8-bit timer/counter with a divide-by-32
prescaler. Figure 26 shows Mode 0 operation.
CORE
ꢅ12
CLK
C/T = 0
INTERRUPT
TL0
TF0
(8 BITS)
CORE
ꢅ12
CLK
C/T = 1
C/T = 0
P3.4/T0
INTERRUPT
TL0
TH0
CONTROL
TR0
TF0
(5 BITS) (8 BITS)
C/T = 1
P3.4/T0
RELOAD
GATE
TH0
CONTROL
(8 BITS)
P3.2/INT0
TR0
Figure 28. Timer/Counter 0, Mode 2
GATE
Mode 3 (Two 8-Bit Timer/Counters)
P3.2/INT0
Mode 3 has different effects on Timer 0 and Timer 1. Timer 1 in
Mode 3 simply holds its count. The effect is the same as setting
TR1 = 0. Timer 0 in Mode 3 establishes TL0 and TH0 as two
separate counters. This configuration is shown in Figure 29.
TL0 uses the Timer 0 control bits: C/T, Gate, TR0, INT0, and
TF0. TH0 is locked into a timer function (counting machine
cycles) and takes over the use of TR1 and TF1 from Timer 1.
Thus, TH0 now controls the Timer 1 interrupt. Mode 3 is
provided for applications requiring an extra 8-bit timer or counter.
Figure 26. Timer/Counter 0, Mode 0
In this mode, the timer register is configured as a 13-bit register. As
the count rolls over from all 1s to all 0s, it sets the timer overflow
flag TF0. The overflow flag, TF0, can then be used to request
an interrupt. The counted input is enabled to the timer when
TR0 = 1 and either Gate = 0 or INT0 = 1. Setting Gate = 1 allows
the timer to be controlled by external input INT0 to facilitate
pulsewidth measurements. TR0 is a control bit in the special
function register TCON; Gate is in TMOD. The 13-bit register
consists of all eight bits of TH0 and the lower five bits of TL0.
The upper three bits of TL0 are indeterminate and should be
ignored. Setting the run flag (TR0) does not clear the registers.
When Timer 0 is in Mode 3, Timer 1 can be turned on and off by
switching it out of, and into, its own Mode 3, or can still be used
by the serial interface as a baud rate generator. In fact, it can be used
in any application not requiring an interrupt from Timer 1 itself.
Mode 1 (16-Bit Timer/Counter)
Mode 1 is the same as Mode 0, except that the timer register is
running with all 16 bits. Mode 1 is shown in Figure 27.
CORE
CLK
CORE
ꢅ12
CLK/12
C/T = 0
C/T = 1
INTERRUPT
TL0
(8 BITS)
TF0
CORE
CLK
ꢅ12
C/T = 0
P3.4/T0
INTERRUPT
CONTROL
TL0
TH0
TR0
TF0
(8 BITS) (8 BITS)
C/T = 1
P3.4/T0
GATE
CONTROL
P3.2/INT0
TR0
INTERRUPT
CORE
CLK/12
TH0
(8 BITS)
TF1
GATE
P3.2/INT0
CONTROL
TR1
Figure 27. Timer/Counter 0, Mode 1
Figure 29. Timer/Counter 0, Mode 3
–32–
REV. E
ADuC812
Timer/Counter 2
T2CON
Control Register
SFR Address
Power-On Default Value
Bit Addressable
C8H
00H
Yes
TF2
EXF2
RCLK
TCLK
EXEN2
TR2
CNT2
CAP2
Table XVII. T2CON SFR Bit Designations
Description
Timer 2 Overflow Flag.
Bit
Name
7
TF2
Set by hardware on a Timer 2 overflow. TF2 will not be set when either RCLK = 1 or TCLK = 1.
Cleared by user software.
Timer 2 External Flag.
Set by hardware when either a capture or reload is caused by a negative transition on T2EX and
EXEN2 = 1.
Cleared by user software.
Receive Clock Enable Bit.
Set by user to enable the serial port to use Timer 2 overflow pulses for its receive clock in serial port
Modes 1 and 3.
Cleared by user to enable Timer 1 overflow to be used for the receive clock.
Transmit Clock Enable Bit.
Set by user to enable the serial port to use Timer 2 overflow pulses for its transmit clock in serial
port Modes 1 and 3.
6
5
4
3
EXF2
RCLK
TCLK
EXEN2
Cleared by user to enable Timer 1 overflow to be used for the transmit clock.
Timer 2 External Enable Flag.
Set by user to enable a capture or reload to occur as a result of a negative transition on T2EX if
Timer 2 is not being used to clock the serial port.
Cleared by user for Timer 2 to ignore events at T2EX.
Timer 2 Start/Stop Control Bit.
Set by user to start Timer 2.
Cleared by user to stop Timer 2.
2
1
0
TR2
CNT2
CAP2
Timer 2 Timer or Counter Function Select Bit.
Set by the user to select counter function (input from external T2 pin).
Cleared by the user to select timer function (input from on-chip core clock).
Timer 2 Capture/Reload Select Bit.
Set by user to enable captures on negative transitions at T2EX if EXEN2 = 1.
Cleared by user to enable autoreloads with Timer 2 overflows or negative transitions at T2EX
when EXEN2 = 1. When either RCLK = 1 or TCLK = 1, this bit is ignored and the timer is
forced to autoreload on Timer 2 overflow.
Timer/Counter 2 Data Registers
Timer/Counter 2 also has two pairs of 8-bit data registers
associated with it. These are used as both timer data registers
and timer capture/reload registers.
TH2 and TL2
Timer 2, data high byte and low byte.
SFR Address = CDH, CCH, respectively.
RCAP2H and RCAP2L
Timer 2, Capture/Reload high byte and low byte.
SFR Address = CBH, CAH, respectively.
REV. E
–33–
ADuC812
Timer/Counter Operation Modes
16-Bit Capture Mode
The following paragraphs describe the operating modes for
Timer/Counter 2. The operating modes are selected by bits in the
T2CON SFR as shown in Table XVIII.
In the Capture mode, there are again two options, which are
selected by bit EXEN2 in T2CON. If EXEN2 = 0, then Timer 2
is a 16-bit timer or counter that, upon overflowing, sets bit TF2,
the Timer 2 overflow bit, that can be used to generate an inter-
rupt. If EXEN2 = 1, then Timer 2 still performs the above, but
a l-to-0 transition on external input T2EX causes the current
value in the Timer 2 registers, TL2 and TH2, to be captured into
registers RCAP2L and RCAP2H, respectively. In addition, the
transition at T2EX causes bit EXF2 in T2CON to be set, and
EXF2, like TF2, can generate an interrupt. The Capture mode
is illustrated in Figure 31.
Table XVIII. TIMECON SFR Bit Designations
RCLK (or) TCLK
CAP2
TR2
MODE
0
0
1
X
0
1
X
X
1
1
1
0
16-Bit Autoreload
16-Bit Capture
Baud Rate
OFF
The baud rate generator mode is selected by RCLK = 1 and/or
TCLK = 1.
16-Bit Autoreload Mode
In Autoreload mode, there are two options, which are selected by
bit EXEN2 in T2CON. If EXEN2 = 0, then when Timer 2 rolls
over, it not only sets TF2 but also causes the Timer 2 registers to
reload with the 16-bit value in registers RCAP2L and RCAP2H,
which are preset by software. If EXEN2 = 1 then Timer 2 still
performs the above, but with the added feature that a 1-to-0
transition at external input T2EX will also trigger the 16-bit reload
and set EXF2. The Autoreload mode is illustrated in Figure 30.
In either case, if Timer 2 is being used to generate the baud rate,
the TF2 interrupt flag will not occur. Therefore Timer 2 inter-
rupts will not occur, so they do not have to be disabled. In this
mode however, the EXF2 flag can still cause interrupts and this
can be used as a third external interrupt.
Baud rate generation will be described as part of the UART
serial port operation in the following pages.
CORE
12
CLK
C/T2 = 0
C/T2 = 1
TL2
(8 BITS)
TH2
(8 BITS)
T2
PIN
CONTROL
TR2
RELOAD
TRANSITION
DETECTOR
RCAP2L
RCAP2H
TF2
TIMER
INTERRUPT
T2EX
PIN
EXF2
CONTROL
EXEN2
Figure 30. Timer/Counter 2, 16-Bit Autoreload Mode
CORE
CLK
12
C/T2 = 0
TL2
(8 BITS)
TH2
(8 BITS)
TF2
C/T2 = 1
T2
PIN
CONTROL
TR2
TIMER
INTERRUPT
CAPTURE
TRANSITION
DETECTOR
RCAP2L
RCAP2H
T2EX
PIN
EXF2
CONTROL
EXEN2
Figure 31. Timer/Counter 2, 16-Bit Capture Mode
–34–
REV. E
ADuC812
UART SERIAL INTERFACE
while the SFR interface to the UART is comprised of SBUF
and SCON, as described below.
The serial port is full-duplex, meaning it can transmit and receive
simultaneously. It is also receive-buffered, meaning it can begin
receiving a second byte before a previously received byte has been
read from the receive register. However, if the first byte still has
not been read by the time reception of the second byte is com-
plete, the first byte will be lost. The physical interface to the
serial data network is via Pins RXD(P3.0) and TXD(P3.1)
SBUF
The serial port receive and transmit registers are both accessed
through the SBUF SFR (SFR address = 99H). Writing to
SBUF loads the transmit register and reading SBUF accesses a
physically separate receive register.
UART Serial Port
SCON
Control Register
SFR Address
Power-On Default Value
Bit Addressable
98H
00H
Yes
SM0
SM1
SM2
REN
TB8
RB8
TI
RI
Table XIX. SCON SFR Bit Designations
Description
UART Serial Mode Select Bits.
Bit
Name
7
6
SM0
SM1
These bits select the Serial Port operating mode as follows:
SM0
SM1
Selected Operating Mode
Mode 0: Shift Register, fixed baud rate (Core_Clk/2)
Mode 1: 8-bit UART, variable baud rate
Mode 2: 9-bit UART, fixed baud rate (Core_Clk/64) or (Core_Clk/32)
Mode 3: 9-bit UART, variable baud rate
0
0
1
1
0
1
0
1
5
4
SM2
REN
Multiprocessor Communication Enable Bit.
Enables multiprocessor communication in Modes 2 and 3. In Mode 0, SM2 should be cleared.
In Mode 1, if SM2 is set, RI will not be activated if a valid stop bit was not received. If SM2 is
cleared, RI will be set as soon as the byte of data has been received. In Modes 2 or 3, if SM2 is
set, RI will not be activated if the received ninth data bit in RB8 is 0. If SM2 is cleared, RI will
be set as soon as the byte of data has been received.
Serial Port Receive Enable Bit.
Set by user software to enable serial port reception.
Cleared by user software to disable serial port reception.
Serial Port Transmit (Bit 9).
The data loaded into TB8 will be the ninth data bit that will be transmitted in Modes 2 and 3.
Serial Port Receiver Bit 9.
3
2
TB8
RB8
The ninth data bit received in Modes 2 and 3 is latched into RB8. For Mode 1, the stop bit is
latched into RB8.
1
0
TI
RI
Serial Port Transmit Interrupt Flag.
Set by hardware at the end of the eighth bit in Mode 0, or at the beginning of the stop bit in
Modes 1, 2, and 3. TI must be cleared by user software.
Serial Port Receive Interrupt Flag.
Set by hardware at the end of the eighth bit in Mode 0, or halfway through the stop bit in
Modes 1, 2, and 3. RI must be cleared by software.
REV. E
–35–
ADuC812
Mode 0 (8-Bit Shift Register Mode)
Mode 2 (9-Bit UART with Fixed Baud Rate)
Mode 0 is selected by clearing both the SM0 and SM1 bits in the
SFR SCON. Serial data enters and exits through RxD. TxD
outputs the shift clock. Eight data bits are transmitted or received.
Transmission is initiated by any instruction that writes to SBUF.
The data is shifted out of the RxD line. The eight bits are
transmitted with the least significant bit (LSB) first, as shown
in Figure 32.
Mode 2 is selected by setting SM0 and clearing SM1. In this
mode, the UART operates in 9-bit mode with a fixed baud rate.
The baud rate is fixed at Core_Clk/64 by default, although by
setting the SMOD bit in PCON, the frequency can be doubled to
Core_Clk/32. Eleven bits are transmitted or received, a start
bit (0), eight data bits, a programmable ninth bit, and a stop bit
(1). The ninth bit is most often used as a parity bit, although it
can be used for anything, including a ninth data bit if required.
MACHINE
CYCLE 1
MACHINE
CYCLE 2
MACHINE
CYCLE 7
MACHINE
CYCLE 8
To transmit, the eight data bits must be written into SBUF. The
ninth bit must be written to TB8 in SCON. When transmission is
initiated, the eight data bits (from SBUF) are loaded onto the
transmit shift register (LSB first). The contents of TB8 are loaded
into the ninth bit position of the transmit shift register. The trans-
mission will start at the next valid baud rate clock. The TI flag
is set as soon as the stop bit appears on TxD.
S1 S2 S3 S4 S5 S6 S1 S2 S3 S4
S4 S5 S6 S1 S2 S3 S4 S5 S6
CORE
CLK
ALE
RxD
(DATA OUT)
DATA BIT 0
DATA BIT 1
DATA BIT 6
DATA BIT 7
TxD
(SHIFT
Reception for Mode 2 is similar to that of Mode 1. The eight
data bytes are input at RxD (LSB first) and loaded onto the
receive shift register. When all eight bits have been clocked in,
the following events occur:
CLOCK)
Figure 32. UART Serial Port Transmission, Mode 0
Reception is initiated when the receive enable bit (REN) is 1 and
the receive interrupt bit (RI) is 0. When RI is cleared, the data
is clocked into the RxD line and the clock pulses are output
from the TxD line.
The eight bits in the receive shift register are latched into SBUF.
The ninth data bit is latched into RB8 in SCON.
The Receiver interrupt flag (RI) is set.
Mode 1 (8-Bit UART, Variable Baud Rate)
This will be the case if, and only if, the following conditions are
met at the time the final shift pulse is generated:
Mode 1 is selected by clearing SM0 and setting SM1. Each data
byte (LSB first) is preceded by a start bit (0) and followed by a
stop bit (1). Therefore 10 bits are transmitted on TxD or received
on RxD. The baud rate is set by the Timer 1 or Timer 2 overflow
rate, or a combination of the two (one for transmission and the
other for reception).
RI = 0, and
Either SM2 = 0, or SM2 = 1 and the received stop bit = 1.
If either of these conditions is not met, the received frame is
irretrievably lost, and RI is not set.
Transmission is initiated by writing to SBUF. The “write to SBUF”
signal also loads a 1 (stop bit) into the ninth bit position of the
transmit shift register. The data is output bit by bit until the stop
bit appears on TxD and the transmit interrupt flag (TI) is auto-
matically set, as shown in Figure 33.
Mode 3 (9-Bit UART with Variable Baud Rate)
Mode 3 is selected by setting both SM0 and SM1. In this mode
the 8051 UART serial port operates in 9-bit mode with a variable
baud rate determined by either Timer 1 or Timer 2. The opera-
tion of the 9-bit UART is the same as for Mode 2, but the baud
rate can be varied as for Mode 1.
STOP BIT
START
BIT
In all four modes, transmission is initiated by any instruction
that uses SBUF as a destination register. Reception is initiated in
Mode 0 by the condition RI = 0 and REN = 1. Reception is
initiated in the other modes by the incoming start bit if REN = 1.
D0
D1
D2
D3
D4
D5
D6
D7
TxD
TI
(SCON.1)
SET INTERRUPT
i.e., READY FOR MORE DATA
UART Serial Port Baud Rate Generation
Mode 0 Baud Rate Generation
The baud rate in Mode 0 is fixed:
Figure 33. UART Serial Port Transmission, Mode 0
Reception is initiated when a 1-to-0 transition is detected on
RxD. Assuming a valid start bit was detected, character reception
continues. The start bit is skipped and the eight data bits are
clocked into the serial port shift register. When all eight bits have
been clocked in, the following events occur:
Mode 0 Baud Rate = Core Clock Frequency 12
(
)
Mode 2 Baud Rate Generation
The baud rate in Mode 2 depends on the value of the SMOD bit
in the PCON SFR. If SMOD = 0, the baud rate is 1/64 of the core
clock. If SMOD = 1, the baud rate is 1/32 of the core clock:
The eight bits in the receive shift register are latched into SBUF.
The ninth bit (Stop bit) is clocked into RB8 in SCON.
The Receiver interrupt flag (RI) is set.
Mode 2 Baud Rate = 2SMOD 64 × Core Clock Frequency
(
)
(
)
Mode 1 and 3 Baud Rate Generation
This will be the case if, and only if, the following conditions are
met at the time the final shift pulse is generated:
The baud rates in Modes 1 and 3 are determined by the overflow
rate in Timer 1 or Timer 2, or both (one for transmit and the
other for receive).
RI = 0, and
Either SM2 = 0 or SM2 = 1 and the received stop bit = 1.
If either of these conditions is not met, the received frame is
irretrievably lost, and RI is not set.
–36–
REV. E
ADuC812
Timer 1 Generated Baud Rates
Modes 1 and 3 Baud Rate =
When Timer 1 is used as the baud rate generator, the baud rates
in Modes 1 and 3 are determined by the Timer 1 overflow rate and
the value of SMOD as follows:
1 16 × Timer 2Overflow Rate
(
)
(
)
Therefore, when Timer 2 is used to generate baud rates, the
timer increments every two clock cycles and not every core
machine cycle as before. Therefore, it increments six times
faster than Timer 1, and baud rates six times faster are possible.
Because Timer 2 has 16-bit autoreload capability, very low baud
rates are still possible.
Modes 1 and 3 Baud Rate =
2SMOD 32 × Timer 1Overflow Rate
(
)
(
)
The Timer 1 interrupt should be disabled in this application.
The timer itself can be configured for either timer or counter
operation, and in any of its three running modes. In the most
typical application, it is configured for timer operation in the
Autoreload mode (high nibble of TMOD = 0010 binary). In that
case, the baud rate is given by the formula:
Timer 2 is selected as the baud rate generator by setting the TCLK
and/or RCLK in T2CON. The baud rates for transmit and receive
can be simultaneously different. Setting RCLK and/or TCLK puts
Timer 2 into its baud rate generator mode as shown in Figure 34.
In this case, the baud rate is given by the formula:
Modes 1 and 3 Baud Rate =
Modes 1 and 3 Baud Rate =
2SMOD 32 × Core Clock 12 × 256 − TH1
[
]
(
)
(
)
(
)
Core Clk 32 × 65536 − RCAP2H, RCAP2L
(
)
(
)
(
[
]
)
Table XX shows some commonly used baud rates and how they
might be calculated from a core clock frequency of 11.0592 MHz
and 12 MHz. Generally speaking, a 5% error is tolerable using
asynchronous (start/stop) communications.
Table XXI shows some commonly used baud rates and how they
might be calculated from a core clock frequency of 11.0592 MHz
and 12 MHz.
Table XXI. Commonly Used Baud Rates, Timer 2
Table XX. Commonly Used Baud Rates, Timer 1
Ideal
Baud
Core
CLK
RCAP2H RCAP2L
Actual
Baud
%
Error
Ideal
Core
Baud CLK
SMOD TH1-Reload Actual
%
Error
Value
Value
Value
Value
Baud
19200 12
–1 (FFH)
–1 (FFH)
–1 (FFH)
–2 (FEH)
–1 (FFH)
–1 (FFH)
–1 (FFH)
–2 (FFH)
–20 (ECH) 19661
–41 (D7H) 9591
–164 (5CH) 2398
–72 (B8H) 1199
–18 (EEH) 19200
–36 (DCH) 9600
–144 (70H) 2400
–32 (E0H) 1200
2.4
0.1
0.1
0.1
0
0
0
0
9600 12
19200 11.0592
1
–7 (F9H)
–3 (FDH)
–3 (FDH)
–12 (F4H)
8929
19200
9600
2400
7
0
0
0
9600
2400
1200
12
12
12
1
0
0
9600
2400
11.0592
11.0592
19200 11.0592
9600
2400
1200
11.0592
11.0592
11.0592
Timer 2 Generated Baud Rates
Baud rates can also be generated using Timer 2. Using Timer 2 is
similar to using Timer 1 in that the timer must overflow 16 times
before a bit is transmitted/received. Because Timer 2 has a 16-bit
Autoreload mode, a wider range of baud rates is possible using
Timer 2.
TIMER 1
OVERFLOW
NOTE: OSCILLATOR FREQUENCY
IS DIVIDED BY 2, NOT 12.
2
0
1
SMOD
CONTROL
CORE
CLK
2
TIMER 2
C/T2 = 0
C/T2 = 1
OVERFLOW
1
1
0
0
TL2
(8 BITS)
TH2
(8 BITS)
RCLK
T2
PIN
RX
CLOCK
16
TR2
TCLK
16
RELOAD
TX
CLOCK
RCAP2L
RCAP2H
NOTE: AVAILABILITY OF ADDITIONAL
EXTERNAL INTERRUPT
EXF
2
TIMER 2
INTERRUPT
T2EX
PIN
CONTROL
EXEN2
TRANSITION
DETECTOR
Figure 34. Timer 2, UART Baud Rates
–37–
REV. E
ADuC812
INTERRUPT SYSTEM
The ADuC812 provides a total of nine interrupt sources with two priority levels. The control and configuration of the interrupt system
is carried out through three interrupt related SFRs.
IE
Interrupt Enable Register
IP
IE2
Interrupt Priority Register
Secondary Interrupt Enable Register
Interrupt Enable
Register
IE
SFR Address
Power-On Default Value
Bit Addressable
A8H
00H
Yes
EA
EADC
ET2
ES
ET1
EX1
ET0
EX0
Table XXII. IE SFR Bit Designations
Description
Bit
Name
7
6
5
4
3
2
1
0
EA
Written by user to enable “1” or disable “0” all interrupt sources.
Written by user to enable “1” or disable “0” ADC interrupt.
Written by user to enable “1” or disable “0” Timer 2 interrupt.
Written by user to enable “1” or disable “0” UART serial port interrupt.
Written by user to enable “1” or disable “0” Timer 1 interrupt.
Written by user to enable “1” or disable “0” External Interrupt 1.
Written by user to enable “1” or disable “0” Timer 0 interrupt.
Written by user to enable “1” or disable “0” External Interrupt 0.
EADC
ET2
ES
ET1
EX1
ET0
EX0
Interrupt Priority
IP
Register
B8H
SFR Address
Power-On Default Value
Bit Addressable
00H
Yes
PSI
PADC
PT2
PS
PT1
PX1
PT0
PX0
Table XXIII. IP SFR Bit Designations
Description
Written by user to select I2C/SPI priority (“1” = High; “0” = Low).
Written by user to select ADC interrupt priority (“1” = High; “0” = Low).
Written by user to select Timer 2 interrupt priority (“1” = High; “0” = Low).
Written by user to select UART serial port interrupt priority (“1” = High; “0” = Low).
Written by user to select Timer 1 interrupt priority (“1” = High; “0” = Low).
Written by user to select External Interrupt 1 priority (“1” = High; “0” = Low).
Written by user to select Timer 0 interrupt priority (“1” = High; “0” = Low).
Written by user to select External Interrupt 0 priority (“1” = High; “0” = Low).
Bit
Name
7
6
5
4
3
2
1
0
PSI
PADC
PT2
PS
PT1
PX1
PT0
PX0
–38–
REV. E
ADuC812
Secondary Interrupt
IE2
Enable Register
SFR Address
Power-On Default Value
Bit Addressable
A9H
00H
No
—
—
—
—
—
—
EPSMI
ESI
Table XXIV. IE2 SFR Bit Designations
Bit
Name
Description
7
6
5
4
3
2
1
0
—
—
—
—
—
—
EPSMI
ESI
Reserved for future use.
Reserved for future use.
Reserved for future use.
Reserved for future use.
Reserved for future use.
Reserved for future use.
Written by user to Enable “1” or Disable “0” power supply monitor interrupt.
Written by user to Enable “1” or Disable “0” I2C/SPI serial port interrupt.
Interrupt Priority
Interrupt Vectors
The Interrupt Enable registers are written by the user to enable
individual interrupt sources, while the Interrupt Priority registers
allow the user to select one of two priority levels for each interrupt.
An interrupt of high priority may interrupt the service routine of
a low priority interrupt. If two interrupts of different priorities
occur at the same time, the higher level interrupt will be served
first. An interrupt cannot be interrupted by another interrupt of
the same priority level. If two interrupts of the same priority level
occur simultaneously, a polling sequence is observed, as shown
in Table XXV.
When an interrupt occurs, the program counter is pushed onto
the stack and the corresponding interrupt vector address is
loaded into the program counter. The interrupt vector addresses
are shown in the Table XXVI.
Table XXVI. Interrupt Vector Addresses
Source
Vector Address
IE0
TF0
IE1
TF1
RI + TI
TF2 + EXF2
ADCI
I2CI + ISPI
PSMI
0003H
000BH
0013H
001BH
0023H
002BH
0033H
003BH
0043H
Table XXV. Priority within an Interrupt Level
Source
Priority
Description
PSMI
IE0
1 (Highest)
2
Power Supply Monitor Interrupt
External Interrupt 0
ADCI
3
ADC Interrupt
TF0
IE1
4
5
Timer/Counter 0 Interrupt
External Interrupt 1
TF1
6
7
8
Timer/Counter 1 Interrupt
I2CI + ISPI
RI + TI
TF2 + EXF2
I2C/SPI Interrupt
Serial Interrupt
Timer/Counter 2 Interrupt
9 (Lowest)
REV. E
–39–
ADuC812
ADuC812 HARDWARE DESIGN CONSIDERATIONS
This section outlines some of the key hardware design consider-
ations that must be addressed when integrating the ADuC812
into any hardware system.
External program memory (if used) must be connected to the
ADuC812 as illustrated in Figure 37. Note that 16 I/O lines
(Ports 0 and 2) are dedicated to bus functions during external
program memory fetches. Port 0 (P0) serves as a multiplexed
address/data bus. It emits the low byte of the program counter
(PCL) as an address, and then goes into a float state awaiting
the arrival of the code byte from the program memory. During
the time that the low byte of the program counter is valid on P0,
the signal ALE (Address Latch Enable) clocks this byte into an
address latch. Meanwhile, Port 2 (P2) emits the high byte of the
program counter (PCH), then PSEN strobes the EPROM and
the code byte is read into the ADuC812.
Clock Oscillator
The clock source for the ADuC812 can come either from an
external source or from the internal clock oscillator. To use the
internal clock oscillator, connect a parallel resonant crystal
between Pins 32 and 33, and connect a capacitor from each pin
to ground as shown below.
ADuC812
XTAL1
EPROM
ADuC812
D0–D7
(INSTRUCTION)
P0
TO INTERNAL
TIMING CIRCUITS
A0–A7
XTAL2
LATCH
ALE
Figure 35. External Parallel Resonant Crystal Connections
A8–A15
OE
P2
ADuC812
PSEN
XTAL1
EXTERNAL
CLOCK
SOURCE
Figure 37. External Program Memory Interface
TO INTERNAL
Note that program memory addresses are always 16 bits wide, even
in cases where the actual amount of program memory used is less
than 64 K bytes. External program execution sacrifices two of the
8-bit ports (P0 and P2) to the function of addressing the program
memory. While executing from external program memory, Ports 0
and 2 can be used simultaneously for read/write access to external
data memory, but not for general-purpose I/O.
TIMING CIRCUITS
XTAL2
Figure 36. Connecting an External Clock Source
Whether using the internal oscillator or an external clock source,
the ADuC812’s specified operational clock speed range is 300 kHz
to 16 MHz. The core is static, and will function all the way
down to dc. But at clock speeds slower that 400 kHz the ADC
will no longer function correctly. Therefore, to ensure specified
operation, use a clock frequency of at least 400 kHz and no
more than 16 MHz.
Though both external program memory and external data memory
are accessed by some of the same pins, the two are completely
independent of each other from a software point of view. For example,
the chip can read/write external data memory while executing
from external program memory.
External Memory Interface
Figure 38 shows a hardware configuration for accessing up to
64 K bytes of external RAM. This interface is standard to any
8051 compatible MCU.
In addition to its internal program and data memories, the
ADuC812 can access up to 64 K bytes of external program
memory (ROM, PROM, etc.) and up to 16 M bytes of exter-
nal data memory (SRAM).
SRAM
ADuC812
To select from which code space (internal or external program
memory) to begin executing instructions, tie the EA (external
access) pin high or low, respectively. When EA is high (pulled
up to VDD), user program execution will start at address 0 of the
internal 8 K bytes Flash/EE code space. When EA is low (tied
to ground) user program execution will start at address 0 of the
external code space. In either case, addresses above 1FFFH
(8K) are mapped to the external space.
D0–D7
(DATA)
P0
LATCH
A0–A7
ALE
P2
A8–A15
OE
RD
Note that a second very important function of the EA pin is
described in the Single Pin Emulation Mode section.
WE
WR
Figure 38. External Data Memory Interface
(64K Address Space)
–40–
REV. E
ADuC812
If access to more than 64K bytes of RAM is desired, a feature
unique to the ADuC812 allows addressing up to 16 MBytes
of external RAM simply by adding an additional latch as illus-
trated in Figure 39.
The best way to implement an external POR function to meet the
above requirements involves the use of a dedicated POR chip, such
as the ADM809/ADM810 SOT-23 packaged PORs from Analog
Devices. Recommended connection diagrams for both active high
ADM810 and active low ADM809 PORs are shown in Figure 41
and Figure 42, respectively.
SRAM
ADuC812
D0–D7
(DATA)
P0
ADuC812
POWER SUPPLY
20
LATCH
LATCH
A0–A7
34
48
DV
DD
ALE
P2
A8–A15
POR
(ACTIVE HIGH)
15
RESET
A16–A23
Figure 41. External Active High POR Circuit
OE
RD
Some active-low POR chips, such as the ADM809, can be used
with a manual push-button as an additional reset source as
illustrated by the dashed line connection in Figure 42.
WE
WR
Figure 39. External Data Memory Interface (16 M Bytes
Address Space)
ADuC812
POWER SUPPLY
In either implementation, Port 0 (P0) serves as a multiplexed
address/data bus. It emits the low byte of the data pointer (DPL) as
an address, which is latched by a pulse of ALE prior to data being
placed on the bus by the ADuC812 (write operation) or the
SRAM (read operation). Port 2 (P2) provides the data pointer
page byte (DPP) to be latched by ALE, followed by the data
pointer high byte (DPH). If no latch is connected to P2, DPP is
ignored by the SRAM and the 8051 standard of 64K byte external
data memory access is maintained.
20
34
48
1kꢃ
DV
DD
POR
(ACTIVE LOW)
15
RESET
OPTIONAL
MANUAL
RESET
PUSH BUTTON
Detailed timing diagrams of external program and data memory
read and write access can be found in the Timing Specifica-
tion sections.
Figure 42. External Active Low POR Circuit
Power Supplies
The ADuC812’s operational power supply voltage range is 2.7 V
to 5.25 V. Although the guaranteed data sheet specifications are
given only for power supplies within 2.7 V to 3.6 V or 10% of
the nominal 5 V level, the chip will function equally well at any
power supply level between 2.7 V and 5.5 V.
Power-On Reset Operation
External POR (power-on reset) circuitry must be implemented to
drive the RESET pin of the ADuC812. The circuit must hold
the RESET pin asserted (high) whenever the power supply
(DVDD) is below 2.5 V. Furthermore, VDD must remain above
2.5 V for at least 10 ms before the RESET signal is deasserted
(low), by which time the power supply must have reached at least
a 2.7 V level. The external POR circuit must be operational
down to 1.2 V or less. The timing diagram in Figure 40 illus-
trates this functionality under three separate events: power-up,
brownout, and power-down. Notice that when RESET is asserted
(high), it tracks the voltage on DVDD. These recommendations
must be adhered to through the manufacturing flow of your
ADuC812 based system as well as during its normal power-on
operation. Failure to adhere to these recommendations can
result in permanent damage to device functionality.
Separate analog and digital power supply pins (AVDD and DVDD,
respectively) allow AVDD to be kept relatively free of noisy digital
signals often present on the system DVDD line. However, though
you can power AVDD and DVDD from two separate supplies if
desired, you must ensure that they remain within 0.3 V of one
another at all times in order to avoid damaging the chip (as per the
Absolute Maximum Ratings section). Therefore it is recommended
that unless AVDD and DVDD are connected directly together,
you connect back-to-back Schottky diodes between them as
shown in Figure 43.
DIGITAL SUPPLY
ANALOG SUPPLY
10ꢄF
10ꢄF
+
–
+
–
2.5V MIN
DV
DD
ADuC812
10ms
MIN
10ms
MIN
1.2V MAX
1.2V MAX
20
5
AV
DD
34 DV
48
DD
0.1ꢄF
0.1ꢄF
21
RESET
6
AGND
35 DGND
47
Figure 40. External POR Timing
Figure 43. External Dual-Supply Connections
REV. E
–41–
ADuC812
As an alternative to providing two separate power supplies, the
user can help keep AVDD quiet by placing a small series resistor
and/or ferrite bead between it and DVDD, and then decoupling
AVDD separately to ground. An example of this configuration is
shown in Figure 44. With this configuration, other analog
circuitry (such as op amps, voltage reference, and so on) can be
powered from the AVDD supply line as well. The user will still
want to include back-to-back Schottky diodes between AVDD
and DVDD in order to protect from power-up and power-down
transient conditions that could separate the two supply voltages
momentarily.
Table XXVII. Typical IDD of Core and Peripherals
VDD = 5 V VDD = 3 V
CORE
(Normal Mode) (1.6 nAs × MCLK) + (0.8 nAs × MCLK) +
6 mA 3 mA
CORE
(Idle Mode)
(0.75 nAs × MCLK) + (0.25 nAs × MCLK) +
5 mA
3 mA
ADC
1.3 mA
250 µA
200 µA
1.0 mA
200 µA
150 µA
DAC (Each)
Voltage Ref
DIGITAL SUPPLY
Since operating DVDD current is primarily a function of clock
speed, the expressions for CORE supply current in Table XXVII
are given as functions of MCLK, the oscillator frequency. Plug
in a value for MCLK in hertz to determine the current consumed
by the core at that oscillator frequency. Since the ADC and DACs
can be enabled or disabled in software, add only the currents
from the peripherals you expect to use. The internal voltage refer-
ence is automatically enabled whenever either the ADC or at
least one DAC is enabled. And again, do not forget to include
current sourced by I/O pins, serial port pins, DAC outputs, and
so forth, plus the additional current drawn during Flash/EE
erase and program cycles.
10ꢄF
1.6ꢃ
10ꢄF
BEAD
+
–
ADuC812
20
5
AV
DD
DD
34 DV
0.1ꢄF
48
0.1ꢄF
21
35
DGND
6
AGND
47
Figure 44. External Single-Supply Connections
Notice that in both Figure 43 and Figure 44, a large value (10 µF)
reservoir capacitor sits on DVDD and a separate 10 µF capacitor
sits on AVDD. Also, local small value (0.1 µF) capacitors are
located at each VDD pin of the chip. As per standard design prac-
tice, be sure to include all of these capacitors, and ensure the
smaller capacitors are close to each AVDD pin with trace lengths as
short as possible. Connect the ground terminal of each of these
capacitors directly to the underlying ground plane. Finally, it
should also be noted that, at all times, the analog and digital
ground pins on the ADuC812 must be referenced to the same
system ground reference point.
A software switch allows the chip to be switched from normal
mode into idle mode, and also into full power-down mode.
Below are brief descriptions of power-down and idle modes.
In idle mode, the oscillator continues to run but is gated off to
the core only. The on-chip peripherals continue to receive the
clock, and remain functional. Port pins and DAC output pins
retain their states in this mode. The chip will recover from idle
mode upon receiving any enabled interrupt, or upon receiving a
hardware reset.
In full power-down mode, the on-chip oscillator stops, and all
on-chip peripherals are shut down. Port pins retain their logic levels
in this mode, but the DAC output goes to a high impedance
state (three-state). The chip will only recover from power-down
mode upon receiving a hardware reset or when power is cycled.
During full power-down mode, the ADuC812 consumes a total
of approximately 5 µA.
Power Consumption
The currents consumed by the various sections of the ADuC812
are shown in Table XXVII. The CORE values given represent
the current drawn by DVDD, while the rest (ADC, DAC, Volt-
age Reference) are pulled by the AVDD pin and can be disabled
in software when not in use. The other on-chip peripherals
(watchdog timer, power supply monitor, and so on) consume
negligible current and are therefore lumped in with the CORE
operating current here. Of course, the user must add any
currents sourced by the DAC or the parallel and serial I/O pins,
in order to determine the total current needed at the ADuC812’s
supply pins. Also, current drawn from the DVDD supply will
increase by approximately 10 mA during Flash/EE erase and
program cycles.
–42–
REV. E
ADuC812
Grounding and Board Layout Recommendations
As with all high resolution data converters, special attention
must be paid to grounding and PC board layout of ADuC812
based designs in order to achieve optimum performance from
the ADC and DACs.
In all of these scenarios, and in more complicated real-life appli-
cations, keep in mind the flow of current from the supplies and
back to ground. Make sure the return paths for all currents are
as close as possible to the paths the currents took to reach their
destinations. For example, do not power components on the
analog side of Figure 45b with DVDD since that would force
return currents from DVDD to flow through AGND. Also, try to
avoid digital currents flowing under analog circuitry, which could
happen if the user placed a noisy digital chip on the left half of the
board in Figure 45c. Whenever possible, avoid large discontinuities
in the ground plane(s) (formed by a long trace on the same
layer), since they force return signals to travel a longer path. And
of course, make all connections to the ground plane directly,
with little or no trace separating the pin from its via to ground.
Although the ADuC812 has separate pins for analog and digital
ground (AGND and DGND), the user must not tie these to two
separate ground planes unless the two ground planes are connected
together very close to the ADuC812, as illustrated in the simpli-
fied example of Figure 45a. In systems where digital and analog
ground planes are connected together somewhere else (for example,
at the system’s power supply), they cannot be connected again
near the ADuC812 since a ground loop would result. In these
cases, tie the ADuC812’s AGND and DGND pins all to the
analog ground plane, as illustrated in Figure 45b. In systems with
only one ground plane, ensure that the digital and analog com-
ponents are physically separated onto separate halves of the board
such that digital return currents do not flow near analog circuitry
and vice versa. The ADuC812 can then be placed between the
digital and analog sections, as illustrated in Figure 45c.
If the user plans to connect fast logic signals (rise/fall time < 5 ns)
to any of the ADuC812’s digital inputs, add a series resistor to
each relevant line to keep rise and fall times longer than 5 ns at the
ADuC812 input pins. A value of 100 or 200 is usually suffi-
cient to prevent high speed signals from coupling capacitively
into the ADuC812 and affecting the accuracy of ADC conversions.
PLACE ANALOG
a.
PLACE DIGITAL
COMPONENTS
HERE
COMPONENTS
HERE
AGND
DGND
PLACE ANALOG
PLACE DIGITAL
COMPONENTS
HERE
b.
COMPONENTS
HERE
AGND
DGND
PLACE DIGITAL
COMPONENTS
HERE
PLACE ANALOG
COMPONENTS
HERE
c.
GND
Figure 45. System Grounding Schemes
REV. E
–43–
ADuC812
DOWNLOAD/DEBUG
ENABLE JUMPER
(NORMALLY OPEN)
DV
DV
DD
DD
1kꢃ
1kꢃ
2-PIN HEADER FOR
EMULATION ACCESS
(NORMALLY OPEN)
49
52 51 50
ADC0
48 47 46 45 44
43
42 41 40
51ꢃ
39
ANALOG INPUT
38
37
36
35
34
33
32
31
30
29
28
27
AV
DV
DD
DD
AV
DD
DGND
DV
DD
AGND
ADuC812
C
REF
XTAL2
XTAL1
V
OUTPUT
11.0592MHz
REF
V
REF
DAC0
DAC1
DAC OUTPUT
DV
DD
ADM810
GND
NOT CONNECTED IN THIS EXAMPLE
V
RST
DV
DD
CC
ADM202
DV
DD
9-PIN D-SUB
FEMALE
C1+
V+
V
CC
GND
1
2
3
4
5
6
7
8
9
C1–
T1OUT
C2+
C2–
V–
R1IN
R1OUT
T1IN
T2OUT
R2IN
T2IN
R2OUT
Figure 46. Typical System Configuration
OTHER HARDWARE CONSIDERATIONS
into download mode, simply connect this jumper and power-
cycle the device (or manually reset the device, if a manual reset
button is available) and it will be ready to receive a new program
serially. With the jumper removed, the device will come up in
normal mode (and run the program) whenever power is cycled
or RESET is toggled.
To facilitate in-circuit programming, plus in-circuit debug and
emulation options, users will want to implement some simple
connection points in their hardware that will allow easy access
to download, debug, and emulation modes.
In-Circuit Serial Download Access
Nearly all ADuC812 designs will want to take advantage of the
in-circuit reprogrammability of the chip. This is accomplished by
a connection to the ADuC812’s UART, which requires an external
RS-232 chip for level translation if downloading code from a PC.
Basic configuration of an RS-232 connection is illustrated in
Figure 46 with a simple ADM202 based circuit. If users would
rather not design an RS-232 chip onto a board, refer to the Appli-
cation Note, uC006–A 4-Wire UART-to-PC Interface, (available
at www.analog.com/microconverter) for a simple (and zero-cost-
per-board) method of gaining in-circuit serial download access
to the ADuC812.
Note that PSEN is normally an output (as described in the External
Memory Interface section), and is sampled as an input only on
the falling edge of RESET (i.e., at power-up or upon an external
manual reset). Note also that if any external circuitry uninten-
tionally pulls PSEN low during power-up or reset events, it could
cause the chip to enter download mode and therefore fail to begin
user code execution as it should. To prevent this, ensure that no
external signals are capable of pulling the PSEN pin low, except
for the external PSEN jumper itself.
Embedded Serial Port Debugger
From a hardware perspective, entry to serial port debug mode is
identical to the serial download entry sequence described above.
In fact, both serial download and serial port debug modes can be
thought of as essentially one mode of operation used in two
different ways.
In addition to the basic UART connections, users will also need
a way to trigger the chip into download mode. This is accom-
plished via a 1 k pull-down resistor that can be jumpered onto
the PSEN pin, as shown in Figure 46. To get the ADuC812
–44–
REV. E
ADuC812
Note that the serial port debugger is fully contained on the
ADuC812 device, (unlike ROM monitor type debuggers) and
therefore no external memory is needed to enable in-system
debug sessions.
Single-Pin Emulation Mode
Also built into the ADuC812 is a dedicated controller for single-pin
in-circuit emulation (ICE) using standard production ADuC812
devices. In this mode, emulation access is gained by connection
to a single pin, the EA pin. Normally, this pin is hardwired either
high or low to select execution from internal or external program
memory space, as described earlier. To enable single-pin emulation
mode, however, users will need to pull the EA pin high through
a 1 k resistor, as shown in Figure 46. The emulator will then
connect to the 2-pin header also shown in Figure 46. To be com-
patible with the standard connector that comes with the single-pin
emulator available from Accutron Limited (www.accutron.com),
use a 2-pin 0.1 inch pitch “Friction Lock” header from Molex
(www.molex.com) such as their part number 22-27-2021. Be sure
to observe the polarity of this header. As represented in Figure 46,
when the Friction Lock tab is at the right, the ground pin should
be the lower of the two pins (when viewed from the top).
Figure 47. Components of the QuickStart Development
System
Enhanced-Hooks Emulation Mode
ADuC812 also supports enhanced-hooks emulation mode. An
enhanced-hooks based emulator is available from Metalink
Corporation (www.metaice.com). No special hardware support
for these emulators needs to be designed onto the board since
these are pod-style emulators where users must replace the chip
on their board with a header device that the emulator pod plugs
into. The only hardware concern is then one of determining if
adequate space is available for the emulator pod to fit into the
system enclosure.
Typical System Configuration
A typical ADuC812 configuration is shown in Figure 46. It sum-
marizes some of the hardware considerations discussed in the
previous paragraphs.
Figure 48. Typical Debug Session
Download—In-Circuit Serial Downloader
The Serial Downloader is a Windows application that allows the
user to serially download an assembled program (Intel Hex format
file) to the on-chip program FLASH memory via the serial COM1
port on a standard PC. Application Note uC004 detailing this
serial download protocol is available at www.analog.com/
microconverter.
QUICKSTART DEVELOPMENT SYSTEM
The QuickStart Development System is a full featured, low cost
development tool suite supporting the ADuC812. The system
consists of the following PC based (Windows® compatible)
hardware and software development tools.
DeBug—In-Circuit Debugger
Hardware:
ADuC812 Evaluation Board, Plug-In
Power Supply and Serial Port Cable
The Debugger is a Windows application that allows the user to
debug code execution on silicon using the MicroConverter UART
serial port. The debugger provides access to all on-chip periph-
erals during a typical debug session as well as single-step and
breakpoint code execution control.
Code Development:
Code Functionality:
8051 Assembler
Windows Based Simulator
In-Circuit Code Download: Serial Downloader
ADSIM—Windows Simulator
In-Circuit Debugger:
Miscellaneous Other:
Serial Port Debugger
The Simulator is a Windows application that fully simulates all
the MicroConverter functionality including ADC and DAC
peripherals. The simulator provides an easy-to-use, intuitive inter-
face to the MicroConverter functionality and integrates many
standard debug features including multiple breakpoints, single
stepping, and code execution trace capability. This tool can be
used both as a tutorial guide to the part as well as an efficient way
to prove code functionality before moving to a hardware platform.
CD-ROM Documentation and
Two Additional Prototype Devices
Figure 47 shows the typical components of a QuickStart
Development System. A brief description of some of the software
tools components in the QuickStart Development System is
given in the following sections.
The QuickStart development tool suite software is freely available at
the Analog Devices MicroConverter website, www.analog.com/
microconverter.
REV. E
–45–
ADuC812
TIMING SPECIFICATIONS1, 2, 3
(AVDD = DVDD = 3.0 V or 5.0 V ꢂ 10%. All specifications TA = TMIN to TMAX, unless otherwise noted.)
12 MHz
Typ
Variable Clock
Parameter
Min
Max
Min
Typ
Max
Unit
CLOCK INPUT (External Clock Driven XTAL1)
tCK
XTAL1 Period
83.33
62.5
20
20
1000
ns
ns
ns
ns
ns
µs
tCKL
tCKH
tCKR
tCKF
XTAL1 Width Low
XTAL1 Width High
XTAL1 Rise Time
XTAL1 Fall Time
ADuC812 Machine Cycle Time
20
20
20
20
20
20
4
tCYC
1
12tCK
NOTES
1AC inputs during testing are driven at DVDD – 0.5 V for a Logic 1 and 0.45 V for a Logic 0. Timing measurements are made at VIH min for a Logic 1 and VIL max for
a Logic 0.
2For timing purposes, a port pin is no longer floating when a 100 mV change from load voltage occurs. A port pin begins to float when a 100 mV change from the
loaded VOH/VOL level occurs.
3CLOAD for Port 0, ALE, PSEN outputs = 100 pF; CLOAD for all other outputs = 80 pF, unless otherwise noted.
4ADuC812 Machine Cycle Time is nominally defined as MCLKIN/12.
tCKR
tCKH
tCKL
tCKF
tCK
Figure 49. XTAL 1 Input
DV – 0.5V
DD
V
– 0.1V
+ 0.1V
V
V
– 0.1V
– 0.1V
LOAD
LOAD
0.2V + 0.9V
TEST POINTS
TIMING
REFERENCE
POINTS
CC
V
V
LOAD
LOAD
0.2V – 0.1V
CC
V
LOAD
LOAD
0.45V
Figure 50. Timing Waveform Characteristics
–46–
REV. E
ADuC812
12 MHz
Max
Variable Clock
Min Max
Parameter
Min
Unit
EXTERNAL PROGRAM MEMORY READ CYCLE
tLHLL
tAVLL
tLLAX
tLLIV
tLLPL
tPLPH
tPLIV
tPXIX
tPXIZ
tAVIV
tPLAZ
tPHAX
ALE Pulsewidth
127
43
53
2tCK – 40
tCK – 40
tCK – 30
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Address Valid to ALE Low
Address Hold after ALE Low
ALE Low to Valid Instruction In
ALE Low to PSEN Low
234
145
4tCK – 100
3tCK – 105
53
205
tCK – 30
3tCK – 45
PSEN Pulsewidth
PSEN Low to Valid Instruction In
Input Instruction Hold after PSEN
Input Instruction Float after PSEN
Address to Valid Instruction In
PSEN Low to Address Float
Address Hold after PSEN High
0
0
0
0
59
312
25
tCK – 25
5tCK – 105
25
MCLK
tLHLL
ALE (O)
tAVLL
tLLPL
tPLPH
tLLIV
tPLIV
PSEN (O)
tPXIZ
tPLAZ
tLLAX
tPXIX
INSTRUCTION
(IN)
PORT 0 (I/O)
PORT 2 (O)
PCL (OUT)
tAVIV
tPHAX
PCH
Figure 51. External Program Memory Read Cycle
–47–
REV. E
ADuC812
12 MHz
Min
Variable Clock
Max
Parameter
Max
Min
Unit
EXTERNAL DATA MEMORY READ CYCLE
tRLRH
tAVLL
tLLAX
tRLDV
tRHDX
tRHDZ
tLLDV
tAVDV
tLLWL
tAVWL
tRLAZ
tWHLH
RD Pulsewidth
400
43
48
6tCK – 100
tCK – 40
tCK – 35
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Address Valid after ALE Low
Address Hold after ALE Low
RD Low to Valid Data In
Data and Address Hold after RD
Data Float after RD
ALE Low to Valid Data In
Address to Valid Data In
ALE Low to RD or WR Low
Address Valid to RD or WR Low
RD Low to Address Float
RD or WR High to ALE High
252
5tCK – 165
0
0
97
2tCK – 70
8tCK – 150
9tCK – 165
3tCK + 50
517
585
300
200
203
3tCK – 50
4tCK – 130
0
123
0
43
tCK – 40
6tCK – 100
MCLK
ALE (O)
tWHLH
PSEN (O)
tLLDV
tLLWL
tRLRH
RD (O)
tAVWL
tRLDV
tRHDZ
tLLAX
tRHDX
tAVLL
tRLAZ
A0–A7 (OUT)
tAVDV
DATA (IN)
PORT 0 (I/O)
PORT 2 (O)
A16–A23
A8–A15
Figure 52. External Data Memory Read Cycle
–48–
REV. E
ADuC812
12 MHz
Min
Variable Clock
Min Max
Parameter
Max
Unit
EXTERNAL DATA MEMORY WRITE CYCLE
tWLWH
tAVLL
tLLAX
tLLWL
tAVWL
tQVWX
tQVWH
tWHQX
tWHLH
WR Pulsewidth
400
43
48
200
203
33
433
33
6tCK – 100
tCK – 40
tCK – 35
3tCK – 50
4tCK – 130
tCK – 50
7tCK – 150
tCK – 50
ns
ns
ns
ns
ns
ns
ns
ns
ns
Address Valid after ALE Low
Address Hold after ALE Low
ALE Low to RD or WR Low
Address Valid to RD or WR Low
Data Valid to WR Transition
Data Setup before WR
300
123
3tCK + 50
6tCK – 100
Data and Address Hold after WR
RD or WR High to ALE High
43
tCK – 40
MCLK
ALE (O)
tWHLH
PSEN (O)
WR (O)
tLLWL
tWLWH
tAVWL
tLLAX
tQVWX
tWHQX
tAVLL
tQVWH
DATA
A0–A7
A16–A23
A8–A15
PORT 2 (O)
Figure 53. External Data Memory Write Cycle
–49–
REV. E
ADuC812
12 MHz
Min Typ Max
Variable Clock
Typ
Parameter
Min
Max
Unit
UART TIMING (Shift Register Mode)
tXLXL
tQVXH
tDVXH
tXHDX
tXHQX
Serial Port Clock Cycle Time
1.0
12tCK
µs
ns
ns
ns
ns
Output Data Setup to Clock
Input Data Setup to Clock
Input Data Hold after Clock
Output Data Hold after Clock
700
300
0
10tCK – 133
2tCK + 133
0
50
2tCK – 117
ALE (O)
tXLXL
TxD
6
7
0
1
(OUTPUT CLOCK)
SET RI
OR
SET TI
tQVXH
tXHQX
RxD
(OUTPUT DATA)
LSB
MSB
BIT6
BIT1
tDVXH
tXHDX
RxD
(INPUT DATA)
MSB
BIT6
BIT1
LSB
Figure 54. UART Timing in Shift Register Mode
–50–
REV. E
ADuC812
Parameter
Min
Max
Unit
I2C COMPATIBLE INTERFACE TIMING
tLOW
SCLOCK Low Pulsewidth
1.3
0.6
0.6
100
0
µs
µs
µs
µs
µs
µs
µs
tHIGH
SCLOCK High Pulsewidth
Start Condition Hold Time
Data Setup Time
tHD; STA
tSU; DAT
tHD; DAT
tSU; STA
tSU; STO
tBUF
Data Hold time
0.9
Setup time for Repeated Start
Stop Condition Setup Time
Bus Free Time between a STOP
Condition and a START Condition
Rise Time for Both SCLOCK and SDATA
Fall Time for Both SCLOCK and SDATA
Pulsewidth of Spike Suppressed
0.6
0.6
1.3
µs
ns
ns
ns
tR
tF
tSUP
300
300
50
1
tBUF
tSUP
tR
SDATA (I/O)
MSB
LSB
ACK
MSB
tHD; STA
tHD; DAT
tSU; DAT
tHD; DAT
tHD; STA
tR
tHIGH
tSU;
STO
tSU; STA
SCLK (I)
1
2–7
8
9
1
PS
S(R)
tF
tSUP
tLOW
STOP
START
REPEATED
START
CONDITION CONDITION
Figure 55. I2C Compatible Interface Timing
–51–
REV. E
ADuC812
Parameter
Min
Typ
Max
Unit
SPI MASTER MODE TIMING (CPHA = 1)
tLOW
tSH
tDAV
tDSU
tDHD
tDF
SCLOCK Low Pulsewidth
SCLOCK High Pulsewidth
Data Output Valid after SCLOCK Edge
Data Input Setup Time before SCLOCK Edge
Data Input Hold Time after SCLOCK Edge
Data Output Fall Time
330
330
ns
ns
ns
ns
ns
ns
ns
ns
ns
50
100
100
10
10
10
10
25
25
25
25
tDR
Data Output Rise Time
tSR
tSF
SCLOCK Rise Time
SCLOCK Fall Time
SCLOCK
(CPOL = 0)
tSL
tSH
tSR
tSF
SCLOCK
(CPOL = 1)
tDAV
tDF
tDR
LSB
MSB
BIT 6–1
BIT 6–1
MOSI
MISO
LSB IN
MSB IN
tDHD
tDSU
Figure 56. SPI Master Mode Timing (CPHA = 1)
–52–
REV. E
ADuC812
Parameter
Min
Typ
Max
Unit
SPI MASTER MODE TIMING (CPHA = 0)
tSL
SCLOCK Low Pulsewidth
330
330
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
tSH
SCLOCK High Pulsewidth
tDAV
tDOSU
tDSU
tDHD
tDF
Data Output Valid after SCLOCK Edge
Data Output Setup before SCLOCK Edge
Data Input Setup Time before SCLOCK Edge
Data Input Hold Time after SCLOCK Edge
Data Output Fall Time
50
150
100
100
10
10
10
10
25
25
25
25
tDR
tSR
Data Output Rise Time
SCLOCK Rise Time
tSF
SCLOCK Fall Time
SCLOCK
(CPOL = 0)
tSL
tSH
tSF
tSR
SCLOCK
(CPOL = 1)
tDAV
tDF
tDOSU
tDR
MSB
BIT 6–1
BIT 6–1
LSB
MOSI
MISO
MSB IN
LSB IN
tDSU tDHD
Figure 57. SPI Master Mode Timing (CPHA = 0)
–53–
REV. E
ADuC812
Parameter
Min
Typ
Max
Unit
SPI SLAVE MODE TIMING (CPHA = 1)
tSS
SS to SCLOCK Edge
0
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
tSL
tSH
SCLOCK Low Pulsewidth
330
330
SCLOCK High Pulsewidth
Data Output Valid after SCLOCK Edge
Data Input Setup Time before SCLOCK Edge
Data Input Hold Time after SCLOCK Edge
Data Output Fall Time
tDAV
tDSU
tDHD
tDF
tDR
tSR
50
100
100
10
10
10
10
25
25
25
25
Data Output Rise Time
SCLOCK Rise Time
tSF
SCLOCK Fall Time
tSFS
SS High after SCLOCK Edge
0
SS
tSFS
tSS
SCLOCK
(CPOL = 0)
tSL
tSH
tSF
tSR
SCLOCK
(CPOL = 1)
tDAV
tDR
tDF
MISO
MOSI
LSB
MSB
BIT 6–1
BIT 6–1
LSB IN
MSB IN
tDSU
tDHD
Figure 58. SPI Slave Mode Timing (CPHA = 1)
–54–
REV. E
ADuC812
Parameter
Min
Typ
Max
Unit
SPI SLAVE MODE TIMING (CPHA = 0)
tSS
SS to SCLOCK Edge
0
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
tSL
tSH
tDAV
tDSU
tDHD
tDF
SCLOCK Low Pulsewidth
330
330
SCLOCK High Pulsewidth
Data Output Valid after SCLOCK Edge
Data Input Setup Time before SCLOCK Edge
Data Input Hold Time after SCLOCK Edge
Data Output Fall Time
50
100
100
10
10
10
10
25
25
25
25
20
tDR
tSR
Data Output Rise Time
SCLOCK Rise Time
tSF
SCLOCK Fall Time
tDOSS
tSFS
Data Output Valid after SS Edge
SS High After SCLOCK Edge
0
SS
tSFS
tSS
SCLOCK
(CPOL = 0)
tSH
tSL
tSR
tSF
SCLOCK
(CPOL = 1)
tDAV
tDOSS
tDF
tDR
MSB
BIT 6–1
BIT 6–1
LSB
MISO
MOSI
MSB IN
LSB IN
tDSU tDHD
Figure 59. SPI Slave Mode Timing (CPHA = 0)
–55–
REV. E
ADuC812
OUTLINE DIMENSIONS
52-Lead Metric Quad Flat Package [MQFP]
(S-52)
Dimensions shown in millimeters
14.15
1.03
0.88
0.73
13.90 SQ
13.65
2.45
MAX
39
27
40
26
SEATING
PLANE
10.20
10.00 SQ
9.80
7.80
REF
TOP VIEW
(PINS DOWN)
VIEW A
PIN 1
52
14
1
13
0.23
0.11
0.65 BSC
0.38
0.22
2.10
2.00
1.95
7ꢁ
0ꢁ
0.10 MIN
COPLANARITY
VIEW A
ROTATED 90ꢁ CCW
COMPLIANT TO JEDEC STANDARDS MO-022-AC-1
56-Lead Lead Frame Chip Scale Package [LFCSP]
8 x 8 mm Body
(CP-56)
Dimensions shown in millimeters
0.30
8.00
BSC SQ
0.23
0.18
0.60 MAX
PIN 1
INDICATOR
0.60 MAX
43
56
1
42
PIN 1
INDICATOR
6.25
6.10 SQ
5.95
7.75
BSC SQ
BOTTOM
VIEW
TOP
VIEW
0.50
0.40
0.30
29
28
14
15
6.50
REF
0.70 MAX
0.65 NOM
1.00
0.90
0.80
12ꢁ MAX
0.05 MAX
0.02 NOM
0.20
REF
COPLANARITY
0.08
0.50 BSC
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MO-220-VLLD-2
–56–
REV. E
ADuC812
Revision History
Location
Page
4/03—Data Sheet changed from REV. D to REV. E.
Updated OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
2/03—Data Sheet changed from REV. C to REV. D.
Added CP-56 Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Global
Edits to GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Added 56-Lead LFCSP PIN CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Updated ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Added I2C COMPATIBLE INTERFACE TIMING Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Added new Figure 55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Updated OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
03/02—Data Sheet changed from REV. B to REV. C.
Edits to FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Edits to GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Edits to FUNCTIONAL BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Edits to SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Edits to PIN CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Edits to PIN FUNCTION DESCRIPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Edits to Figure 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Edits to SERIAL PERIPHERAL INTERFACE Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Edits to TABLE XI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Edits to TABLE XXIII . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Edits to TABLES XXIV, XXV, and XXVI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
10/01—Data Sheet changed from REV. A to REV. B.
Entire Data Sheet Revised . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . All
REV. E
–57–
–58–
–59–
–60–
相关型号:
ADUC812BCPZ-REEL
IC 8-BIT, FLASH, 11.0592 MHz, MICROCONTROLLER, PQCC56, LEAD FRAME, CSP-56, Microcontroller
ADI
ADUC814ARU
8-BIT, FLASH, 16.78 MHz, MICROCONTROLLER, PDSO28, 4.40 X 9.70 MM, MO-153AE, TSSOP-28
ROCHESTER
ADUC814ARU-REEL7
8-BIT, FLASH, 16.78 MHz, MICROCONTROLLER, PDSO28, 4.40 X 9.70 MM, MO-153AE, TSSOP-28
ROCHESTER
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