TRF7964A [TI]
MULTI-PROTOCOL FULLY INTEGRATED 13.56-MHz RFID READER/WRITER IC; 多协议完全集成的13.56MHz RFID读/写器IC型号: | TRF7964A |
厂家: | TEXAS INSTRUMENTS |
描述: | MULTI-PROTOCOL FULLY INTEGRATED 13.56-MHz RFID READER/WRITER IC |
文件: | 总76页 (文件大小:3009K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
TRF7964A
www.ti.com
SLOS787A –MAY 2012–REVISED JUNE 2012
MULTI-PROTOCOL FULLY INTEGRATED 13.56-MHz RFID
READER/WRITER IC
Check for Samples: TRF7964A
1 Introduction
1.1 Features
1
• Completely Integrated Protocol Handling for
ISO15693, ISO18000-3, ISO14443A/B, and
FeliCa
• Integrated Voltage Regulator Output for Other
System Components (MCU, Peripherals,
Indicators), 20 mA (Max)
• Integrated State Machine for ISO14443A
Anticollision (Broken Bytes) Operation
• Input Voltage Range: 2.7 VDC to 5.5 VDC
• Programmable Output Power: +20 dBm
(100 mW), +23 dBm (200 mW)
• Programmable Modulation Depth
• Dual Receiver Architecture With RSSI for
Elimination of "Read Holes" and Adjacent
Reader System or Ambient In-Band Noise
Detection
• Programmable Power Modes for Ultra Low-
Power System Design (Power Down <1 µA)
• Programmable I/O Voltage Levels From
1.8 VDC to 5.5 VDC
• Parallel or SPI Interface (With 128-Byte FIFO)
• Temperature Range: -40°C to 110°C
• 32-Pin QFN Package (5 mm x 5 mm)
• Programmable System Clock Frequency
Output (RF, RF/2, RF/4) from 13.56-MHz or
27.12-MHz Crystal or Oscillator
1.2 Applications
•
•
•
•
•
Public Transport or Event Ticketing
Passport or Payment (POS) Reader Systems
Product Identification or Authentication
Medical Equipment or Consumables
Access Control, Digital Door Locks
1.3 Description
The TRF7964A is an integrated analog front end and data-framing device for a 13.56-MHz RFID system.
Built-in programming options make it suitable for a wide range of applications for proximity and vicinity
identification systems.
Built-in user-configurable programming options make it suitable for a wide range of applications. The
TRF7964A is configured by selecting the desired protocol in the control registers. Direct access to all
control registers allows fine tuning of various reader parameters as needed.
Documentation, reference designs, EVM, and TI MCU (MSP430, ARM) source code are available.
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date. Products conform to
specifications per the terms of the Texas Instruments standard warranty. Production
processing does not necessarily include testing of all parameters.
Copyright © 2012, Texas Instruments Incorporated
TRF7964A
SLOS787A –MAY 2012–REVISED JUNE 2012
www.ti.com
VDD_I/O
MUX
PHASE&
AMPLITUDE
DETECTOR
I/O_0
RSSI
(AUX)
LOGIC
GAIN
RX_IN1
RX_IN2
I/O_1
STATE
CONTROL
LOGIC
RF Level
Detector
I/O_2
RSSI
(EXTERNAL)
I/O_3
[CONTROL
REGISTERS&
COMMAND
LOGIC]
I/O_4
RSSI
(MAIN)
PHASE&
AMPLITUDE
DETECTOR
I/O_5
GAIN
FILTER
& AGC
I/O_6
DIGITIZER
DECODER
MCU
INTERFACE
VDD_PA
TX_OUT
VSS_PA
I/O_7
ISO
PROTOCOL
HANDLING
IRQ
SYS_CLK
DATA_CLK
VIN
TRANSMITTER ANALOG
FRONT END
128 BYTE
FIFO
BIT
FRAMING
FRAMING
SERIAL
CONVERSION
CRC & PARITY
VDD_A
BAND_GAP
VSS_A
VDD_RF
VSS_RF
EN
EN2
DIGITAL CONTROL
STATE MACHINE
ASK/OOK
MOD
VOLTAGE SUPPLY REGULATOR SYSTEMS
[SUPPLY REGULATORS , REFERENCE VOLTAGES ]
VDD_X
VSS
OSC_IN
CRYSTAL / OSCILLATOR
TIMING SYSTEM
VSS_D
OSC_OUT
Figure 1-1. Block Diagram
1.3.1 Detailed Description
RFID – Reader/Writer
The TRF7964A is a high performance 13.56-MHz HF RFID Transceiver IC composed of an integrated
analog front end (AFE) and a built-in data framing engine for ISO15693, ISO14443A, ISO14443B, and
FeliCa. This includes data rates up to 848 kbps for ISO14443 with all framing and synchronization tasks
on board (in default mode). This architecture enables the customer to build a complete cost-effective yet
high-performance multi-protocol 13.56-MHz RFID system together with a low-cost microcontroller (for
example, MSP430).
Other standards and even custom protocols can be implemented by using two of the Direct Modes that
the device offers. These Direct Modes (0 and 1) allow the user to fully control the analog front end (AFE)
and also gain access to the raw subcarrier data or the unframed but already ISO formatted data and the
associated (extracted) clock signal.
The receiver system has a dual input receiver architecture. The receivers also include various automatic
and manual gain control options. The received input bandwidth can be selected to cover a broad range of
input subcarrier signal options.
The received signal strength from transponders, ambient sources, or internal levels is available through
the RSSI register. The receiver output is selectable among a digitized subcarrier signal and any of the
integrated subcarrier decoders. The selected subcarrier decoder delivers the data bit stream and the data
clock as outputs.
The TRF7964A also includes a receiver framing engine. This receiver framing engine performs the CRC
or parity check, removes the EOF and SOF settings, and organizes the data in bytes for ISO14443-A/B,
ISO15693, and FeliCa protocols. Framed data is then accessible to the microcontroller (MCU) through a
128-byte FIFO register.
2
Introduction
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VDD
VDD
VDD_X
VDD_I/O
TX_OUT
Matching
MCU
(MSP430 or ARM)
Parallel
or SPI
TRF7964A
RX_IN 1
RX_IN2
VSS
VIN
XIN
Supply: 2.7 V – 5.5 V
Crystal
13.56 MHz
Figure 1-2. Application Block Diagram
A parallel or serial interface (SPI) can be used for the communication between the MCU and the
TRF7964A reader. When the built-in hardware encoders and decoders are used, transmit and receive
functions use a 128-byte FIFO register. For direct transmit or receive functions, the encoders and
decoders can be bypassed so that the MCU can process the data in real time. The TRF7964A supports
data communication levels from 1.8 V to 5.5 V for the MCU I/O interface. The transmitter has selectable
output-power levels of 100 mW (+20 dBm) or 200 mW (+23 dBm) equivalent into a 50-Ω load when using
a 5-V supply.
The transmitter supports OOK and ASK modulation with selectable modulation depth. The TRF7964A also
includes a data transmission engine that comprises low-level encoding for ISO15693, ISO14443A/B and
FeliCa. Included with the transmit data coding is the automatic generation of Start Of Frame (SOF), End
Of Frame (EOF), Cyclic Redundancy Check (CRC), or parity bits.
Several integrated voltage regulators ensure a proper power-supply noise rejection for the complete
reader system. The built-in programmable auxiliary voltage regulator VDD_X (pin 32), is able to deliver up to
20 mA to supply a microcontroller and additional external circuits within the reader system.
Table 1-1. Supported Protocols
Supported Protocols
ISO-14443A/B
FeliCa
ISO-15693,
ISO-18000-3
(Mode 1)
Device
212 kbps,
424 kbps
106 kbps
212 kbps
424 kbps
848 kbps
TRF7964A
√
√
√
√
√
√
1.4 Ordering Information
Packaged Devices(1)
Package Type(2)
Transport Media
Quantity
TRF7964ARHBT
250
RHB-32
Tape and Reel
TRF7964ARHBR
3000
(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
Web site at www.ti.com.
(2) Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are available at
www.ti.com/sc/package.
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Introduction
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1
Introduction .............................................. 1
1.1 Features ............................................. 1
1.2 Applications .......................................... 1
1.3 Description ........................................... 1
1.4 Ordering Information ................................. 3
Physical Characteristics ............................... 5
2.1 Terminal Functions .................................. 5
Electrical Specifications ............................... 8
3.1 Absolute Maximum Ratings .......................... 8
3.2 Recommended Operating Conditions ............... 8
3.3 Dissipation Ratings .................................. 8
3.4 Electrical Characteristics ............................ 9
5.3 Receiver – Analog Section ......................... 16
5.4 Receiver – Digital Section .......................... 18
5.5 Oscillator Section ................................... 23
5.6 Transmitter – Analog Section ...................... 24
5.7 Transmitter – Digital Section ....................... 25
5.8
Transmitter – External Power Amplifier and
2
3
Subcarrier Detector ................................. 26
5.9
TRF7964A IC Communication Interface ........... 26
5.10 Special Direct Mode for Improved MIFARE
Compatibility ........................................ 47
5.11 Direct Commands from MCU to Reader ........... 47
Register Description .................................. 51
6.1 Register Preset ..................................... 51
6.2 Register Overview .................................. 51
6.3 Detailed Register Description ...................... 52
System Design ......................................... 68
7.1 Layout Considerations .............................. 68
6
7
8
4
5
Application Schematic and Layout
Considerations ......................................... 10
4.1
TRF7964A Reader System Using Parallel
Microcontroller Interface ............................ 10
TRF7964A Reader System Using SPI With SS
4.2
Mode ................................................ 11
7.2
Impedance Matching TX_Out (Pin 5) to 50 Ω ...... 68
Detailed System Description ........................ 12
5.1 System Block Diagram ............................. 12
5.2 Power Supplies ..................................... 12
7.3 Reader Antenna Design Guidelines ................ 70
Revision History ....................................... 71
4
Contents
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2 Physical Characteristics
2.1 Terminal Functions
RHB PACKAGE
(TOP VIEW)
32
31
30
29
28
27
26
25
VDD_A
VIN
1
I/0_7
I/0_6
I/0_5
I/0_4
I/0_3
I/0_2
I/0_1
I/0_0
24
23
22
21
20
19
18
17
2
3
4
5
6
7
8
VDD_RF
VDD_PA
TX_OUT
VSS_PA
VSS_RX
RX_IN1
Pad
9
10
11
12
13
14
15
16
Figure 2-1. Pin Assignments
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Physical Characteristics
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Table 2-1. Terminal Functions
TERMINAL
(1)
TYPE
DESCRIPTION
NAME
NO.
1
VDD_A
VIN
OUT
SUP
OUT
INP
Internal regulated supply (2.7 V to 3.4 V) for analog circuitry
External supply input to chip (2.7 V to 5.5 V)
2
VDD_RF
VDD_PA
3
Internal regulated supply (2.7 V to 5 V), normally connected to VDD_PA (pin 4)
Supply for PA; normally connected externally to VDD_RF (pin 3)
RF output (selectable output power, 100 mW or 200 mW, with VDD = 5 V)
Negative supply for PA; normally connected to circuit ground
Negative supply for RX inputs; normally connected to circuit ground
Main RX input
4
TX_OUT
VSS_PA
5
OUT
SUP
SUP
INP
6
VSS_RX
7
RX_IN1
RX_IN2
VSS
8
9
INP
Auxiliary RX input
10
11
SUP
OUT
Chip substrate ground
BAND_GAP
Bandgap voltage (VBG = 1.6 V); internal analog voltage reference
Selection between ASK and OOK modulation (0 = ASK, 1 = OOK) for Direct Mode 0 or 1.
Can be configured as an output to provide the received analog signal output.
Interrupt request
ASK/OOK
IRQ
12
13
14
BID
OUT
INP
External data modulation input for Direct Mode 0 or 1
Subcarrier digital data output (see registers 0x1A and 0x1B)
Negative supply for internal analog circuits; connected to GND
Supply for I/O communications (1.8 V to VIN) level shifter. VIN should be never exceeded.
I/O pin for parallel communication
MOD
OUT
SUP
INP
VSS_A
VDD_I/O
I/O_0
I/O_1
15
16
17
18
BID
BID
I/O pin for parallel communication
I/O pin for parallel communication
I/O_2
I/O_3
I/O_4
I/O_5
19
20
21
22
BID
BID
BID
BID
TX_Enable (in Special Direct Mode)
I/O pin for parallel communication
TX_Data (in Special Direct Mode)
I/O pin for parallel communication
Slave Select signal in SPI mode
I/O pin for parallel communication
Data clock output in Direct Mode 1 and Special Direct Mode
I/O pin for parallel communication
I/O_6
I/O_7
23
24
BID
BID
MISO for serial communication (SPI)
Serial bit data output in Direct Mode 1 or subcarrier signal in Direct Mode 0
I/O pin for parallel communication.
MOSI for serial communication (SPI)
Selection of power down mode. If EN2 is connected to VIN, then VDD_X is active during power
down mode 2 (for example, to supply the MCU).
EN2
25
26
INP
INP
DATA_CLK
Data Clock input for MCU communication (parallel and serial)
If EN = 1 (EN2 = don't care) the system clock for MCU is configured. Depending on the crystal
that is used, options are as follows (see register 0x09):
SYS_CLK
27
OUT
13.56-MHz crystal: Off, 3.39 MHz, 6.78 MHz, or 13.56 MHz
27.12-MHz crystal: Off, 6.78 MHz, 13.56 MHz, or 27.12 MHz
If EN = 0 and EN2 = 1, then system clock is set to 60 kHz
Chip enable input (If EN = 0, then chip is in sleep or power-down mode).
Negative supply for internal digital circuits
Crystal or oscillator output
EN
28
29
30
INP
SUP
OUT
INP
VSS_D
OSC_OUT
Crystal or oscillator input
OSC_IN
31
OUT
Crystal oscillator output
(1) SUP = Supply, INP = Input, BID = Bidirectional, OUT = Output
Physical Characteristics
6
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Table 2-1. Terminal Functions (continued)
TERMINAL
NAME
(1)
TYPE
DESCRIPTION
NO.
32
Internally regulated supply (2.7 V to 3.4 V) for digital circuit and external devices (for example,
MCU)
VDD_X
OUT
SUP
Thermal Pad
PAD
Chip substrate ground
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3 Electrical Specifications
(1) (2)
3.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)
VIN
IIN
Input voltage range
Maximum current VIN
-0.3 V to 6 V
150 mA
2 kV
HBM (Human-Body Model)
CDM (Charged-Device Model)
MM (Machine Model)
ESD
Electrostatic discharge rating
500 V
200 V
Any condition
140°C
TJ
Maximum operating virtual junction temperature
Storage temperature range
(3)
Continuous operation, long-term reliability
125°C
TSTG
-55°C to 150°C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only and functional operation of the device at these or any other conditions beyond those indicated under Operating Conditions are not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) All voltage values are with respect to substrate ground terminal VSS
.
(3) The maximum junction temperature for continuous operation is limited by package constraints. Operation above this temperature may
result in reduced reliability or lifetime of the device.
3.2 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
2.7
-40
-40
TYP
5
MAX UNIT
VIN
TA
TJ
Operating input voltage
5.5
110
125
V
Operating ambient temperature
Operating virtual junction temperature
25
25
°C
°C
3.3 Dissipation Ratings
POWER RATING(2)
A ≤ 25°C
2.7 W
(1)
PACKAGE
θJC
θJC
T
T
A ≤ 85°C
RHB (32 pin)
31°C/W
36.4°C/W
1.1 W
(1) This data was taken using the JEDEC standard high-K test PCB.
(2) Power rating is determined with a junction temperature of 125°C. This is the point where distortion starts to increase substantially.
Thermal management of the final PCB should strive to keep the junction temperature at or below 125°C for best performance and long-
term reliability.
8
Electrical Specifications
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3.4 Electrical Characteristics
Typical operating conditions are TA = 25°C, VIN = 5 V, Full-Power mode (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
All building blocks disabled, including supply-
voltage regulators; measured after 500-ms settling
time (EN = 0, EN2 = 0)
IPD1
Supply current in Power Down Mode 1
0.5
5
µA
The SYS_CLK generator and VDD_X remain active
to support external circuitry; measured after 100-ms
settling time (EN = 0, EN2 = 1)
Supply current in Power Down Mode 2 (Sleep
Mode)
IPD2
120
200
µA
Oscillator running, supply-voltage regulators in low-
consumption mode (EN = 1, EN2 = x)
ISTBY
ION1
ION2
Supply current in stand-by mode
1.9
10.5
70
3.5
14
78
mA
mA
mA
Supply current without antenna driver current
Supply current – TX (half power)
Oscillator, regulators, RX and AGC active, TX is off
Oscillator, regulators, RX and AGC and TX active,
POUT = 100 mW
Oscillator, regulators, RX and AGC and TX active,
POUT = 200 mW
ION3
Supply current – TX (full power)
130
150
mA
VPOR
VBG
Power-on reset voltage
Bandgap voltage (pin 11)
Input voltage at VIN
1.4
1.5
2
2.6
1.7
V
V
Internal analog reference voltage
1.6
Regulated output voltage for analog circuitry (pin
1)
VDD_A
VIN = 5 V
3.1
3.1
3.5
3.4
3.8
V
VDD_X
Regulated supply for external circuitry
Maximum output current of VDD_X
Output voltage pin 32, VIN = 5 V
Output current pin 32, VIN = 5 V
Half-power mode, VIN = 2.7 V to 5.5 V
Full-power mode, VIN = 2.7 V to 5.5 V
3.8
20
12
6
V
IVDD_Xmax
mA
8
4
(1)
RRFOUT
Antenna driver output resistance
Ω
RRFIN
RX_IN1 and RX_IN2 input resistance
4
10
20
kΩ
Maximum RF input voltage at RX_IN1 and
RX_IN2
VRF_INmax
VRF_INmax should not exceed VIN
3.5
Vpp
fSUBCARRIER= 424 kHz
1.4
2.1
2.5
3
Minimum RF input voltage at RX_IN1 and
RX_IN2 (input sensitivity)(2)
VRF_INmin
mVpp
fSUBCARRIER = 848 kHz
fSYS_CLK
fC
SYS_CLK frequency
Carrier frequency
In power mode 2, EN = 0, EN2 = 1
Defined by external crystal
25
2
60
120
kHz
13.56
MHz
Time until oscillator stable bit is set (register
0x0F)(3)
tCRYSTAL
fD_CLKmax
VIL
Crystal run-in time
3
8
ms
MHz
V
Depends on capacitive load on the I/O lines,
recommendation is 2 MHz(4)
Maximum DATA_CLK frequency(4)
Input voltage - logic low
10
0.2 x
VDD_I/O
I/O lines, IRQ, SYS_CLK, DATA_CLK, EN, EN2
I/O lines, IRQ, SYS_CLK, DATA_CLK, EN, EN2
0.8 x
VDD_I/O
VIH
Input voltage threshold, logic high
V
ROUT
Output resistance I/O_0 to I/O_7
Output resistance RSYS_CLK
500
200
800
400
Ω
Ω
RSYS_CLK
DATA_CLK time high or low, one half of
DATA_CLK at 50% duty cycle
tLO/HI
Depends on capacitive load on the I/O lines(4)
250
62.5
200
200
50
ns
ns
ns
tSTE,LEAD
tSTE,LAG
Slave select lead time, slave select low to clock
Slave select lag time, last clock to slave Select
high
tSU,SI
MOSI input data setup time
MOSI input data hold time
MISO input data setup time
MISO input data hold time
MISO output data valid time
15
15
15
15
30
ns
ns
ns
ns
ns
tHD,SI
tSU,SO
tHD,SO
tVALID,SO
DATA_CLK edge to MISO valid, CL ≤ 30 pF
50
75
(1) Antenna driver output resistance
(2) Measured with subcarrier signal at RX_IN1 or RX_IN2 and measured the digital output at MOD pin with register 0x1A bit 6 = 1.
(3) Depends on the crystal parameters and components
(4) Recommended DATA_CLK speed is 2 MHz; higher data clock depends on the capacitive load. Maximum SPI clock speed should not
exceed 10 MHz. This clock speed is acceptable only when external capacitive load is less than 30 pF. MISO driver has a typical output
resistance of 400 Ω (12-ns time constant when 30-pF load used).
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4 Application Schematic and Layout Considerations
4.1 TRF7964A Reader System Using Parallel Microcontroller Interface
4.1.1 General Application Considerations
Figure 4-1 shows the most flexible TRF7964A application schematic. Both ISO15693, ISO14443 and
FeliCa systems can be addressed. Due to the low clock frequency on the DATA_CLK line, the parallel
interface is the most robust way to connect the TRF7964A with the MCU.
Figure 4-1 shows matching to a 50-Ω port, which allows connecting to a properly matched 50-Ω antenna
circuit or RF measurement equipment (for example, a spectrum analyzer or power meter).
4.1.2 Schematic
Figure 4-1 shows a sample application schematic for a parallel MCU interface.
OSC_OUT
3
JTAG
057-014-2
2
1
GND1OUT
IN GND2
C24 27pF
TDO/TDI
TDI
TMS
VCC
C23
27pF
OSC_IN
4
X4-1 -2
X4-3 -4
X4-5 -6
X4-7 -8
X4-9 -10
X4
X4
X4
X4
X4
X
TCK
GND
RST_NMI
GND
GND
R4 100R
X4-11 4-12
X4-13 4-14
VCC
X
SMA-142-0701-801/806
X3
(+2.7VDC - 5.5VDC)
VIN
C26
C25
2.2uF
0.01uF
TP
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
1
VCC
SYS_CLK
C19
0.01uF
C20
GND
VCC
2
GND
C16
C15
0.01uF
C18
2.2uF
GND
C17
R5
47k
2.2uF
3
X2
RST_NMI
TCK
TMS
TDI
TDO/TDI
2.2uF
4
EN
0.01uF
TCK
5
TMS
RST_NMI
C1
GND
6
R6
10k
MC-921
GND
GND
7
8
1
2
3
4
5
6
7
8
24
23
22
21
20
19
18
17
0.1uF
P4.7/TBCLK
P4.6/TBOUTH/ACLK
P4.5/TB2
VDD_A
VIN
I/O_7
I/O_6
I/O_5
I/O_4
GND
C6 10pF
9
C2
1500pF
C13
12pF
GND
10
11
12
13
14
15
16
17
18
19
20
TRF7964A
33
VDD_RF
VDD_PA
TX_OUT
VSS_PA
VSS_RX
RX_IN1
L3
1.5uH
P4.4/TB1
R3
0
L2
L1
P4.3/TB0
MOD
IRQ
ASK/OOK
GND(PAD) I/O_3
P4.2/TB2
R2
0
330nH
150nH
I/O_2
I/O_1
I/0_0
P4.1/TB1
C11 C10
8
C
C7 C4
R1
6.8k
C14
68pF
C12
12pF
1500pF
C3
GND
P4.0/TB0
1200pF
27pF 100pF 220pF
680pF
GND
GND
GND
C5
C9
GND GND
TXD
RXD
DATA_CLK
680pF
1200pF
GND
GND
GND
GND
C21
0.01uF
GND
C22
2.2uF
GND
Figure 4-1. Application Schematic – Parallel MCU Interface
An MSP430F2370 (32kB Flash, 2kB RAM) is shown in Figure 4-1. Minimum MCU requirements depend
on application requirements and coding style. If only one ISO protocol or a limited command set of a
protocol needs to be supported, MCU Flash and RAM requirements can be significantly reduced. Be
aware that recursive inventory and anticollision commands require more RAM than single slotted
operations. For example, current reference firmware for ISO15693 (with host interface) is approximately
8kB, using 512B RAM; for all supported protocols (also with same host interface) the reference firmware is
approximately 12kB and uses a minimum of 1kB RAM. An MCU capable of running its GPIOs at
13.56 MHz is required for Direct Mode 0 operations.
10
Application Schematic and Layout Considerations
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4.2 TRF7964A Reader System Using SPI With SS Mode
4.2.1 General Application Considerations
Figure 4-2 shows the TRF7964A application schematic optimized for both ISO15693 and ISO14443
systems using the Serial Port Interface (SPI). Short SPI lines, proper isolation of radio frequency lines,
and a proper ground area are essential to avoid interference. The recommended clock frequency on the
DATA_CLK line is 2 MHz.
Figure 4-2 shows matching to a 50-Ω port, which allows connecting to a properly matched 50-Ω antenna
circuit or RF measurement equipment (for example, a spectrum analyzer or power meter).
4.2.2 Schematic
Figure 4-2 shows a sample application schematic for SPI with an SS mode MCU interface.
OSC_OUT
3
JTAG
2
1
GND1OUT
IN GND2
057-014-2
X4-1 -2
X4-3 -4
X4-5 -6
X4-7 -8
X4-9 -10
C24 27pF
TDO/TDI
TDI
TMS
TCK
GND
VCC
C23
27pF
OSC_IN
4
X4
X4
X4
X4
X4
X
GND
GND
RST_NMI
X4-11 4-12
X4-13 4-14
R4 100R
VCC
(+2.7VDC - 5.5VDC)
VIN
X
SMA-142-0701-801/806
X3
C26
C25
2.2uF
0.01uF
TP
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
1
VCC
SYS_CLK
C19
C20
2.2uF
VCC
2
GND
GND
X2
GND
C16
C15
C18
2.2uF
C17
R5
47k
3
0.01uF
RST_NMI
TCK
2.2uF
4
EN
0.01uF
GND
0.01uF
TCK
TMS
5
RST_NMI
C1
GND
TMS
6
R6
10k
MC-921
GND
TDI
7
8
TDO/TDI
1
24
23
22
21
20
19
18
17
0.1uF
P3.1
P4.7/TBCLK
P4.6/TBOUTH/ACLK
P4.5/TB2
VDD_A
VIN
I/O_7
I/O_6
I/O_5
I/O_4
GND
C6 10pF
2
3
4
5
6
7
8
9
P3.2
C2
1500pF
C13
12pF
TRF7964A
33
GND
10
11
12
13
14
15
16
17
18
19
20
P3.7
VDD_RF
VDD_PA
TX_OUT
VSS_PA
VSS_RX
RX_IN1
L3
1.5uH
P3.0
P4.4/TB1
R3
0
L2
L1
P3.6
P4.3/TB0
MOD
IRQ
ASK/OOK
VCC
GND(PAD) I/O_3
P4.2
P4.2
P4.2/TB2
R2
0
330nH
150nH
I/O_2
I/O_1
I/0_0
C7
VDD_X
P4.1/TB1
C11 C10
8
C
C4
R1
6.8k
C14
68pF
C12
12pF
1500pF
C3
GND
P4.0/TB0
680pF
1200pF
27pF 100pF 220pF
GND
GND
C5
GND
P3.0
P3.1
P3.2
C9
GND GND
TXD
RXD
DATA_CLK
680pF
1200pF
GND
GND
GND
GND
C21
0.01uF
GND
C22
2.2uF
GND
Figure 4-2. Application Schematic – SPI With SS Mode MCU Interface
An MSP430F2370 (32kB Flash, 2kB RAM) is shown in Figure 4-2. Minimum MCU requirements depend
on application requirements and coding style. If only one ISO protocol or a limited command set of a
protocol needs to be supported, MCU Flash and RAM requirements can be significantly reduced and user
should be aware that recursive inventory and anticollision commands require more RAM than single
slotted operations. For example, current reference firmware for ISO15693 (with host interface) is
approximately 8kB, using 512B RAM and for all supported protocols (also with same host interface) the
reference firmware is approximately 12kB and uses a minimum of 1kB RAM. An MCU capable of running
its GPIOs at 13.56 MHz is required for Direct Mode 0 operations.
Copyright © 2012, Texas Instruments Incorporated
Application Schematic and Layout Considerations
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5 Detailed System Description
5.1 System Block Diagram
Figure 5-1shows a block diagram of the TRF7964A.
VDD_I/O
MUX
PHASE&
AMPLITUDE
DETECTOR
I/O_0
RSSI
(AUX)
LOGIC
GAIN
RX_IN1
RX_IN2
I/O_1
STATE
CONTROL
LOGIC
RF Level
Detector
I/O_2
RSSI
(EXTERNAL)
I/O_3
[CONTROL
REGISTERS&
COMMAND
LOGIC]
I/O_4
RSSI
(MAIN)
PHASE&
AMPLITUDE
DETECTOR
I/O_5
GAIN
FILTER
& AGC
I/O_6
DIGITIZER
DECODER
MCU
INTERFACE
VDD_PA
TX_OUT
VSS_PA
I/O_7
ISO
PROTOCOL
HANDLING
IRQ
SYS_CLK
DATA_CLK
VIN
TRANSMITTER ANALOG
FRONT END
128 BYTE
FIFO
BIT
FRAMING
FRAMING
SERIAL
CONVERSION
CRC & PARITY
VDD_A
BAND_GAP
VSS_A
VDD_RF
VSS_RF
EN
EN2
DIGITAL CONTROL
STATE MACHINE
ASK/OOK
MOD
VOLTAGE SUPPLY REGULATOR SYSTEMS
[SUPPLY REGULATORS , REFERENCE VOLTAGES ]
VDD_X
VSS
OSC_IN
CRYSTAL / OSCILLATOR
TIMING SYSTEM
VSS_D
OSC_OUT
Figure 5-1. System Block Diagram
5.2 Power Supplies
The TRF7964A positive supply input VIN (pin 2) sources three internal regulators with output voltages
VDD_RF, VDD_A and VDD_X. All regulators use external bypass capacitors for supply noise filtering and must
be connected as indicated in reference schematics. These regulators provide a high power supply reject
ratio (PSRR) as required for RFID reader systems. All regulators are supplied by VIN (pin 2).
The regulators are not independent and have common control bits in register 0x0B for output voltage
setting. The regulators can be configured to operate in either automatic or manual mode (register 0x0B,
bit 7). The automatic regulator setting mode ensures an optimal compromise between PSRR and the
highest possible supply voltage for RF output (to ensure maximum RF power output). The manual mode
allows the user to manually configure the regulator settings.
5.2.1 Supply Arrangements
Regulator Supply Input: VIN
The positive supply at VIN (pin 2) has an input voltage range of 2.7 V to 5.5 V. VIN provides the supply
input sources for three internal regulators with the output voltages VDD_RF, VDD_A, and VDD_X. External
bypass capacitors for supply noise filtering must be used (per reference schematics).
NOTE
VIN must be the highest voltage supplied to the TRF7964A.
12
Detailed System Description
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RF Power Amplifier Regulator: VDD_RF
The VDD_RF (pin 3) regulator is supplying the RF power amplifier. The voltage regulator can be set for
either 5-V or 3-V operation. External bypass capacitors for supply noise filtering must be used (per
reference schematics). When configured for 5-V manual-operation, the VDD_RF output voltage can be set
from 4.3 V to 5 V in 100-mV steps. In 3-V manual-operation, the output can be programmed from 2.7 V to
3.4 V in 100-mV steps. The maximum output current capability for 5-V operation is 150 mA and for 3-V
operation is 100 mA.
Analog Supply Regulator: VDD_A
Regulator VDD_A (pin 1) supplies the analog circuits of the device. The output voltage setting depends on
the input voltage and can be set for 5-V and 3-V operation. When configured for 5-V manual-operation,
the output voltage is fixed at 3.4 V. External bypass capacitors for supply noise filtering must be used (per
reference schematics). When configured for 3-V manual-operation, the VDD_A output can be set from 2.7 V
to 3.4 V in 100-mV steps (see Table 5-2).
Note: the configuration of VDD_A and VDD_X regulators are not independent from each other. The VDD_A
output current should not exceed 20 mA.
Digital Supply Regulator: VDD_X
The digital supply regulator VDD_X (pin 32) provides the power for the internal digital building blocks and
can also be used to supply external electronics within the reader system. When configured for 3-V
operation, the output voltage can be set from 2.7 to 3.4 V in 100-mV steps. External bypass capacitors for
supply noise filtering must be used (per reference schematics).
Note: the configuration of the VDD_A and VDD_X regulators are not independent from each other. The VDD_X
output current should not exceed 20 mA.
The RF power amplifier regulator (VDD_RF), analog supply regulator (VDD_A) and digital supply regulator
(VDD_X) can be configured to operate in either automatic or manual mode described in Section 5.2.2. The
automatic regulator setting mode ensures an optimal compromise between PSRR and the highest
possible supply voltage to ensure maximum RF power output.
By default, the regulators are set in automatic regulator setting mode. In this mode, the regulators are
automatically set every time the system is activated by setting EN input High or each time the automatic
regulator setting bit, B7 in register 0x0B is set to a 1. The action is started on the 0 to 1 transition. This
means that, if the user wants to re-run the automatic setting from a state in which the automatic setting bit
is already high, the automatic setting bit (B7 in register 0x0B) should be changed: 1-0-1.
By default, the regulator setting algorithm sets the regulator outputs to a "Delta Voltage" of 250 mV below
VIN, but not higher than 5 V for VDD_RF and 3.4 V for VDD_A and VDD_A. The "Delta Voltage" in automatic
regulator mode can be increased up to 400 mV (for details, see bits B0 to B2 in register 0x0B).
Power Amplifier Supply: VDD_PA
The power amplifier of the TRF7964A is supplied through VDD_PA(pin 4). The positive supply pin for the RF
power amplifier is externally connected to the regulator output VDD_RF (pin 3).
I/O Level Shifter Supply: VDD_I/O
The TRF7964A has a separate supply input VDD_I/O (pin 16) for the built-in I/O level shifter. The supported
input voltage ranges from 1.8 V to VIN, not exceeding 5.5 V. Pin 16 is used to supply the I/O interface pins
(I/O_0 to I/O_7), IRQ, SYS_CLK, and DATA_CLK pins of the reader. In typical applications, VDD_I/O is
directly connected to VDD_X, while VDD_X also supplies the MCU. This ensures that the I/O signal levels of
the MCU match the logic levels of the TRF7964A.
Negative Supply Connections: VSS, VSS_TX, VSS_RX, VSS_A, VSS_PA
The negative supply connections VSS_X of each functional block are all externally connected to GND.
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Detailed System Description
13
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The substrate connection is VSS (pin 10), the analog negative supply is VSS_A (pin 15), the logic negative
supply is VSS_D (pin 29), the RF output stage negative supply is VSS_PA (pin 6), and the negative supply for
the RF receiver VSS_RX (pin 7).
5.2.2 Supply Regulator Settings
The input supply voltage mode of the reader needs to be selected. This is done in the Chip Status Control
register (0x00). Bit 0 in register 0x00 selects between 5-V or 3-V input supply voltage. The default
configuration is 5 V, which reflects an operating supply voltage range of 4.3 V to 5.5 V. If the supply
voltage is below 4.3 V, the 3-V configuration should be used.
The various regulators can be configured to operate in automatic or manual mode. This is done in the
Regulator and I/O Control register (0x0B) as shown in Table 5-1 and Table 5-2.
Table 5-1. Supply Regulator Setting: 5-V System
(1)
Register
Address
(hex)
Option Bits Setting in Regulator Control Register
Comments
B7
B6
B5
B4
B3
B2
B1
B0
Automatic Mode (default)
0B
1
1
1
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
1
1
0
1
0
0
Automatic regulator setting 250-mV difference
Automatic regulator setting 350-mV difference
Automatic regulator setting 400-mV difference
0B
0B
Manual Mode
0B
0B
0B
0B
0B
0B
0B
0B
0
0
0
0
0
0
0
0
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
VDD_RF = 5 V, VDD_A = 3.4 V, VDD_X = 3.4 V
VDD_RF = 4.9 V, VDD_A = 3.4 V, VDD_X = 3.4 V
VDD_RF = 4.8 V, VDD_A = 3.4 V, VDD_X = 3.4 V
VDD_RF = 4.7 V, VDD_A = 3.4 V, VDD_X = 3.4 V
VDD_RF = 4.6 V, VDD_A = 3.4 V, VDD_X = 3.4 V
VDD_RF = 4.5 V, VDD_A = 3.4 V, VDD_X = 3.4 V
VDD_RF = 4.4 V, VDD_A = 3.4 V, VDD_X = 3.4 V
VDD_RF = 4.3 V, VDD_A = 3.4 V, VDD_X = 3.4 V
(1) x = Don't care
Table 5-2. Supply Regulator Setting: 3-V System
(1)
Register
Address
(hex)
Option Bits Setting in Regulator Control Register
Comments
B7
B6
B5
B4
B3
B2
B1
B0
Automatic Mode (default)
0B
1
1
1
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
1
1
0
1
0
0
Automatic regulator setting 250-mV difference
Automatic regulator setting 350-mV difference
Automatic regulator setting 400-mV difference
0B
0B
Manual Mode
0B
0B
0B
0B
0B
0B
0B
0B
0
0
0
0
0
0
0
0
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
VDD_RF = 3.4 V, VDD_A = 3.4 V, VDD_X = 3.4 V
VDD_RF = 3.3 V, VDD_A = 3.3 V, VDD_X = 3.3 V
VDD_RF = 3.2 V, VDD_A = 3.2 V, VDD_X = 3.2 V
VDD_RF = 3.1 V, VDD_A = 3.1 V, VDD_X = 3.1 V
VDD_RF = 3.0 V, VDD_A = 3.0 V, VDD_X = 3.0 V
VDD_RF = 2.9 V, VDD_A = 2.9 V, VDD_X = 2.9 V
VDD_RF = 2.8 V, VDD_A = 2.8 V, VDD_X = 2.8 V
VDD_RF = 2.7 V, VDD_A = 2.7 V, VDD_X = 2.7 V
(1) x = Don't care
14
Detailed System Description
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The regulator configuration function adjusts the regulator outputs by default to 250 mV below VIN level, but
not higher than 5 V for VDD_RF , 3.4 V for VDD_A and VDD_X. This ensures the highest possible supply
voltage for the RF output stage while maintaining an adequate PSRR (power supply rejection ratio).
To further improve the PSRR, it is possible to increase the target voltage difference across VDD_X and
VDD_A from its default to 350 mV or even 400 mV (for details see Regulator and I/O Control register (0x0B)
definition in Table 5-1 and Table 5-2.)
5.2.3 Power Modes
The chip has several power states, which are controlled by two input pins (EN and EN2) and several bits
in the chip status control register (0x00) (see Table 5-3).
(1)
Table 5-3. Power Modes
Chip
Regulator
Control
Register
(0x0B)
Typical
Power
Out
Time
(From
Previous
State)
Status
Control
Register
(0x00)
SYS_CLK
(13.56
MHz)
Typical
Current
(mA)
Trans-
mitter
SYS_CLK
(60 kHz)
Mode
EN2
EN
Receiver
VDD_X
(dBm)
Mode 4 (Full Power)
at 5 VDC
approx. 20-
25 µs
X
X
X
X
1
1
1
1
21
20
31
30
07
07
07
07
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
X
X
X
X
ON
ON
ON
ON
105
68
23
17
20
14
Mode 4 (Full Power)
at 3.3 VDC
Mode 3 (Half Power)
at 5 VDC
approx. 20-
25 µs
82
Mode 3 (Half Power)
at 3.3 VDC
53
approx. 20-
25 µs
Mode 2 at 5 VDC
Mode 2 at 3.3 VDC
Mode 1 at 5 VDC
Mode 1 at 3.3 VDC
X
X
X
X
X
1
1
1
1
1
03
02
01
00
81
07
00
07
00
07
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
X
X
X
X
X
ON
ON
ON
ON
ON
13
10
5
—
—
—
approx. 20-
25 µs
OFF
OFF
OFF
3
Standby Mode at 5
VDC
3
—
—
—
—
4.8 ms
Standby Mode at 3.3
VDC
X
1
0
1
0
0
80
X
00
X
OFF
OFF
OFF
OFF
OFF
OFF
ON
OFF
OFF
X
ON
ON
2
Power Down Mode
2 (Sleep)
ON
OFF
0.120
<0.001
1.5 ms
Start
Power Down Mode
1 (Total PD)
X
X
OFF
(1) X = Don't care
Table 5-3 shows the configuration for the different power modes when using a 5-V or 3-V system supply.
The main reader enable signal is pin EN. When EN is set high, all of the reader regulators are enabled,
the 13.56-MHz oscillator is running and the SYS_CLK (output clock for external micro controller) is also
available.
The input pin EN2 has two functions:
•
A direct connection from EN2 to VIN to ensure the availability of the regulated supply VDD_X and an
auxiliary clock signal (60 kHz, SYS_CLK) for an external MCU. This mode (EN = 0, EN2 = 1) is
intended for systems in which the MCU is also being supplied by the reader supply regulator (VDD_X
)
and the MCU clock is supplied by the SYS_CLK output of the reader. This allows the MCU supply and
clock to be available during sleep mode.
•
EN2 enables the start-up of the reader system from complete power down (EN = 0, EN2 = 0). In this
case the EN input is being controlled by the MCU (or other system device) that is without supply
voltage during complete power down (thus unable to control the EN input). A rising edge applied to the
EN2 input (which has an approximately 1-V threshold level) starts the reader supply system and 13.56-
MHz oscillator (identical to condition EN = 1).
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When user MCU is controlling EN and EN2, a delay of 5 ms between EN and EN2 must be used. If the
MCU controls only EN, EN2 is recommended to be connected to either VIN or GND, depending on the
application MCU requirements for VDD_X and SYS_CLK.
NOTE
Using EN = 1 and EN2 = 1 in parallel at start up should not be done as it can cause incorrect
operation.
This start-up mode lasts until all of the regulators have settled and the 13.56-MHz oscillator has stabilized.
If the EN input is set high (EN = 1) by the MCU (or other system device), the reader stays active. If the EN
input is not set high (EN = 0) within 100 µs after the SYS_CLK output is switched from auxiliary clock (60
kHz) to high-frequency clock (derived from the crystal oscillator), the reader system returns to complete
Power-Down Mode1. This option can be used to wake-up the reader system from complete Power Down
(PD Mode 1) by using a pushbutton switch or by sending a single pulse.
After the reader EN line is high, the other power modes are selected by control bits within the chip status
control register (0x00). The power mode options and states are listed in Table 5-3.
When EN is set high (or on rising edge of EN2 and then confirmed by EN = 1) the supply regulators are
activated and the 13.56-MHz oscillator started. When the supplies are settled and the oscillator frequency
is stable, the SYS_CLK output is switched from the auxiliary frequency of 60 kHz to the 13.56-MHz
frequency derived from the crystal oscillator. At this point, the reader is ready to communicate and perform
the required tasks. The MCU can then program the chip status control register 0x00 and select the
operation mode by programming the additional registers.
•
•
•
Stand-by Mode (bit 7 = 1 of register 0x00), the reader is capable of recovering to full operation in
100 µs.
Mode 1 (active mode with RF output disabled, bit 5 = 0 and bit 1 = 0 of register 0x00) is a low power
mode which allows the reader to recover to full operation within 25 µs.
Mode 2 (active mode with only the RF receiver active, bit 1 = 1 of register 0x00) can be used to
measure the external RF field (as described in RSSI measurements paragraph) if reader-to-reader
anticollision is implemented.
•
Modes 3 and 4 (active modes with the entire RF section active, bit 5 = 1 of register 0x00) are the
normal modes used for normal transmit and receive operations.
5.3 Receiver – Analog Section
5.3.1 Main and Auxiliary Receivers
The TRF7964A has two receiver inputs: RX_IN1 (pin 8) and RX_IN2 (pin 9). Each of the input is
connected to an external capacitive voltage divider to ensure that the modulated signal from the tag is
available on at least one of the two inputs. This architecture eliminates any possible communication holes
that may occur from the tag to the reader.
The two RX inputs (RX_IN1 and RX_IN2) are multiplexed into two receivers - the main receiver and the
auxiliary receiver. Only the main receiver is used for reception, the auxiliary receiver is used for signal
quality monitoring. Receiver input multiplexing is controlled by bit B3 in the Chip Status Control register
(address 0x00).
After startup, RX_IN1 is multiplexed to the main receiver which is composed of an RF envelope detection,
first gain and band-pass filtering stage, second gain and filtering stage with AGC. Only the main receiver
is connected to the digitizing stage which output is connected to the digital processing block. The main
receiver also has an RSSI measuring stage, which measures the strength of the demodulated signal
(subcarrier signal).
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The primary function of the auxiliary receiver is to monitor the RX signal quality by measuring the RSSI of
the demodulated subcarrier signal (internal RSSI). After startup, RX_IN2 is multiplexed to the auxiliary
receiver. The auxiliary receiver has an RF envelope detection stage, first gain and filtering with AGC stage
and finally the auxiliary RSSI block.
The default MUX setting is RX_IN1 connected to the main receiver and RX_IN2 connected to the auxiliary
receiver. To determine the signal quality, the response from the tag is detected by the "main" (pin RX_IN1)
and "auxiliary" (pin RX_IN2) RSSI. Both values measured and stored in the RSSI level register (address
0x0F). The MCU can read the RSSI values from the TRF7964A RSSI register and make the decision if
swapping the input- signals is preferable or not. Setting B3 in Chip Status Control register (address 0x00)
to 1 connects RX_IN1 (pin 8) to the auxiliary received and RX_IN2 (pin 9) to the main receiver. This
mechanism needs to be used to avoid reading holes.
The main and auxiliary receiver input stages are RF envelope detectors. The RF amplitude at RX_IN1 and
RX_IN2 should be approximately 3 VPP for a VINsupply level greater than 3.3 V. If the VIN level is lower,
the RF input peak-to-peak voltage level should not exceed the VINlevel.
5.3.2 Receiver Gain and Filter Stages
The first gain and filtering stage has a nominal gain of 15 dB with an adjustable band-pass filter. The
band-pass filter has programmable 3d-B corner frequencies between 110 kHz to 450 kHz for the high-
pass filter and 570 kHz to 1500 kHz for the low-pass filter. After the band-pass filter, there is another gain-
and-filtering stage with a nominal gain of 8 dB and with frequency characteristics identical to the first band-
pass stage.
The internal filters are configured automatically depending on the selected ISO communication standard in
the ISO Control register (address 0x01). If required, additional fine tuning can be done by writing directly
to the RX special setting registers (address 0x0A).
The main receiver also has a second receiver gain and digitizer stage which is included in the AGC loop.
The AGC loop is activated by setting the bit B2 = 1 in the Chip Status Control register (0x00). When
activated, the AGC continuously monitors the input signal level. If the signal level is significantly higher
than an internal threshold level, gain reduction is activated.
By default, the AGC is frozen after the first 4 pulses of the subcarrier signal. This prevents the AGC from
interfering with the reception of the remaining data packet. In certain situations, this AGC freeze is not
optimal, so it can be removed by setting B0 = 1 in the RX special setting register (address 0x0A).
Table 5-4. RX Special Setting Register (0x0A)
Bit
Function
Comments
B7
Bandpass from 110 kHz to 570 kHz
Appropriate for any 212-kHz subcarrier systems (for example, FeliCa)
Appropriate for 424-kHz subcarrier systems (for example, used in
ISO15693)
B6
B5
Bandpass from 200 kHz to 900 kHz
Bandpass from 450 kHz to 1.5 MHz
Bandpass from 100 kHz to 1.5 MHz
Appropriate for Manchester-coded 106-kbps 848-kHz subcarrier systems
(for example, used in ISO14443A)
Appropriate for highest bit rate (848 kbps) used in high-bit-rate ISO14443B.
Gain is reduced by 7 dB.
B4
B3
00 = no gain reduction
01 = gain reduction for 5 dB
10 = gain reduction for 10 dB
11 = gain reduction for 15 dB
Sets the RX digital gain reduction (changing the window of the digitizing
comparator)
B2
B1
AGC activation level change. From 5 times the minimum RX digitizing level
to 3 times the minimum digitizing level. The minimum RX digitizing level can
be adjusted by B2 and B3 (gain reduction)
0 = 5 times minimum digitizing level
1 = 3 times minimum digitizing level
AGC action is not limited in time or to the start of receive. AGC action can
be done any time during receive process. The AGC can only increase and,
therefore, clips on the peak RX level during the enable period. AGC level is
reset automatically at the beginning of each receive start frame.
0 = AGC freeze after 16 subcarrier edges
1 = AGC always on during receive
B0
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Table 5-4 shows the various settings for the receiver analog section. It is important to note that setting B4,
B5, B6, and B7 to 0 results to a band-pass characteristic of 240 kHz to 1.4 MHz, which is appropriate for
ISO14443B 106 kbps, ISO14443A/B data-rates of 212 kbps and 424 kbps and FeliCa 424 kbps.
5.4 Receiver – Digital Section
The output of the TRF7964A analog receiver block is a digitized subcarrier signal and is the input to the
digital receiver block. This block includes a Protocol Bit Decoder section and the Framing Logic section.
The protocol bit decoders convert the subcarrier coded signal into a serial bit stream and a data clock.
The decoder logic is designed for maximum error tolerance. This enables the decoder section to
successfully decode even partly corrupted subcarrier signals that otherwise would be lost due to noise or
interference.
In the framing logic section, the serial bit stream data is formatted in bytes. Special signals such as the
start of frame (SOF), end of frame (EOF), start of communication, and end of communication are
automatically removed. The parity bits and CRC bytes are also checked and removed. This "clean" data is
then sent to the 128 byte FIFO register where it can be read by the external microcontroller system.
Providing the data this way, in conjunction with the timing register settings of the TRF7964A means the
firmware developer has to know about much less of the finer details of the ISO protocols to create a very
robust application, especially in low cost platforms where code space is at a premium and high
performance is still required.
The start of the receive operation (successfully received SOF) sets the IRQ-flags in the IRQ and Status
Register (0x0C). The end of the receive operation is signaled to the external system MCU by setting pin
13 (IRQ) to high. When data is received in the FIFO, an interrupt is sent to the MCU to signal that there is
data to be read from the FIFO. The FIFO status register (0x1C) should be used to provide the number of
bytes that should be clocked out during the actual FIFO read.
Any error in the data format, parity, or CRC is detected and notified to the external system by an interrupt-
request pulse. The source condition of the interrupt request pulse is available in the IRQ status register
(0x0C). The main register controlling the digital part of the receiver is the ISO Control register (0x01). By
writing to this register, the user selects the protocol to be used. With each new write in this register, the
default presets are reloaded in all related registers, so no further adjustments in other registers are
needed for proper operation.
NOTE
If register setting changes are needed for fine tuning the system, they must be done after
setting the ISO Control register (0x01).
The framing section also supports the bit-collision detection as specified in ISO14443A. When a bit
collision is detected, an interrupt request is sent and a flag is set in the IRQ and Status Register (0x0C).
The position of the bit collision is written in two registers: Collision Position Register (0x0E) and partly in
Collision Position and Interrupt Mask Register (0x0D) (bits B6 and B7).
The collision position is presented as sequential bit number, where the count starts immediately after the
start bit. This means a collision in the first bit of a UID would give the value 00 0001 0000 in these
registers when their contents are combined after being read. (the count starts with 0 and the first 16 bits
are the command code and the Number of Valid Bits (NVB) byte)
The receive section also contains two timers. The RX wait time timer is controlled by the value in the RX
Wait Time Register (0x08). This timer defines the time interval after the end of the transmit operation in
which the receive decoders are not active (held in reset state). This prevents false detections resulting
from transients following the transmit operation. The value of the RX Wait Time Register (0x08) defines
the time in increments of 9.44 µs. This register is preset at every write to ISO Control Register (0x01)
according to the minimum tag response time defined by each standard.
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The RX no response timer is controlled by the RX No Response Wait Time Register (0x07). This timer
measures the time from the start of slot in the anticollision sequence until the start of tag response. If there
is no tag response in the defined time, an interrupt request is sent and a flag is set in the IRQ Status
Register (0x0C). This enables the external controller to be relieved of the task of detecting empty slots.
The wait time is stored in the register in increments of 37.76 µs. This register is also preset, automatically
for every new protocol selection.
The digitized output of the analog receiver is at the input of the digital portion of the receiver. This input
signal is the subcarrier coded signal, which is a digital representation of modulation signal on the RF
envelope.
The digital part of the receiver consists of two sections which partly overlap. The first section contains the
bit decoders for the various protocols. The bit decoders convert the subcarrier coded signal to a bit stream
and also the data clock. Thus the subcarrier coded signal is transformed to serial data and the data clock
is extracted. The decoder logic is designed for maximum error tolerance. This enables the decoders to
successfully decode even partly corrupted (due to noise or interference) subcarrier signals.
The second section contains the framing logic for the protocols supported by the bit decoder section. In
the framing section, the serial bit stream data is formatted in bytes. In this process, special signals like the
SOF (start of frame), EOF (end of frame), start of communication, end of communication are automatically
removed. The parity bits and CRC bytes are checked and also removed. The end result is "clean or raw"
data which is sent to the 128-byte FIFO register where it can be read out by the external microcontroller
system.
The start of the receive operation (successfully received SOF) sets the flags in the IRQ and Status
register. The end of the receive operation is signaled to the external system (MCU) by sending an interrupt
request (pin 13 IRQ). If the receive data packet is longer than 96 bytes, an interrupt is sent to the MCU
when the received data occupies 75% of the FIFO capacity to signal that the data should be removed
from the FIFO.
Any error in data format, parity or CRC is detected and the external system is made aware of the error by
an interrupt request pulse. The nature of the interrupt request pulse is available in the IRQ and Status
register (address 0x0C). The bit coding description of this register is shown in Section 6.3.3.1.
The main register controlling the digital part of the receiver is the ISO Control register (address 0x01). By
writing to this register, the user selects the protocol to be used. At the same time (with each new write in
this register) the default preset in all related registers is done, so no further adjustments in other registers
are needed for proper operation. Table 5-5 shows the coding of the ISO Control register (0x01).
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Table 5-5. Coding of the ISO Control Register
Bit
Signal Name
Function
Comments
1 = No RX CRC
0 = RX CRC
B7
rx_crc_n
Receiving without CRC
0 = output is subcarrier data
B6
B5
dir_mode
rfid
Direct mode type
RFID mode
1 = output is bit stream and clock from decoder selected by ISO bits
0 = RFID reader mode
1 = Reserved (should be set to 0)
B4
B3
B2
B1
B0
iso_4
iso_3
iso_2
iso_1
iso_0
RFID
RFID
RFID
RFID
RFID
See Table 5-6 for B0:B4 settings based on ISO protocol used by application.
See Table 5-6 for B0:B4 settings based on ISO protocol used by application.
See Table 5-6 for B0:B4 settings based on ISO protocol used by application.
See Table 5-6 for B0:B4 settings based on ISO protocol used by application.
See Table 5-6 for B0:B4 settings based on ISO protocol used by application.
Table 5-6. Coding of the ISO Control Register For RFID Mode (B5 = 0)
Iso_4
Iso_3
Iso_2
Iso_1
Iso_0
Protocol
Remarks
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
1
1
1
1
0
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
ISO15693 low bit rate, one subcarrier, 1 out of 4
ISO15693 low bit rate, one subcarrier, 1 out of 256
ISO15693 high bit rate, one subcarrier, 1 out of 4
ISO15693 high bit rate, one subcarrier, 1 out of 256
ISO15693 low bit rate, double subcarrier, 1 out of 4
ISO15693 low bit rate, double subcarrier, 1 out of 256
ISO15693 high bit rate, double subcarrier, 1 out of 4
ISO15693 high bit rate, double subcarrier, 1 out of 256
ISO14443A, bit rate 106 kbps
Default for RFID IC
RX bit rate when TX rate
different than RX rate (see
register 0x03)
0
1
0
0
1
ISO14443 A high bit rate 212 kbps
0
0
0
1
1
1
0
0
1
1
1
0
0
1
0
ISO14443 A high bit rate 424 kbps
ISO14443 A high bit rate 848 kbps
ISO14443B, bit rate 106 kbps
RX bit rate when TX rate
different than RX rate (see
register 0x03)
0
1
1
0
1
ISO14443 B high bit rate 212 kbps
0
0
1
1
1
1
1
1
0
0
1
1
1
1
0
1
0
0
1
1
1
0
1
1
0
1
1
0
0
1
ISO14443 B high bit rate 424 kbps
ISO14443 B high bit rate 848 kbps
Reserved
Reserved
FeliCa 212 kbps
FeliCa 424 kbps
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The framing section also supports the bit collision detection as specified in ISO14443A. In the event of a
detected bit collision, an interrupt request is sent and flag set in the IRQ and Status registers. The position
of the bit collision is written in two registers: the Collision Position register (0x0E) and partly in the
Collision Position and Interrupt Mask register (0x0D), in which only the bits B7 and B6 are used for
collision position. The collision position is presented as sequential bit number, where the counting starts
immediately after the start bit. This means, the collision in the first bit of the UID would give value 00 0001
0000 in the collision position registers (the counting starts with 0 and the first 16 bits are the command
code and the NVB byte).
The receive part also contains two timers. The RX wait time timer setting is controlled by the value in the
RX Wait Time register (0x08). This timer defines the time after the end of transmit operation in which the
receive decoders are not active (held in reset state). This prevents any incorrect detections from occurring
as a result of transients following the transmit operation. The value of the RX Wait Time register defines
this time with increments of 9.44 µs. This register is preset at every write to the ISO Control register (0x01)
according to the minimum tag response time defined by each standard.
The RX no response timer setting is controlled by the RX No Response Wait Time register (0x07). This
timer measures the time from the start of slot in the anticollision sequence until the start of tag response. If
there is no tag response in the defined time, an interrupt request is sent and a flag is set in IRQ Status
Control register. This enables the external controller to be relieved of the task of detecting empty slots.
The wait time is stored in the register with increments of 37.76 µs. This register is also preset,
automatically, for every new protocol selection.
5.4.1 Received Signal Strength Indicator (RSSI)
The TRF7964A incorporates in total three independent RSSI building blocks: Internal Main RSSI, Internal
Auxiliary RSSI, and External RSSI. The internal RSSI blocks are measuring the amplitude of the
subcarrier signal; the External RSSI block measures the amplitude of the RF carrier signal at the receiver
input.
5.4.1.1 Internal RSSI – Main and Auxiliary Receivers
Each receiver path has its own RSSI block to measure the envelope of the demodulated RF signal
(subcarrier). Internal Main RSSI and Internal Auxiliary RSSI are identical however connected to different
RF input pins. The Internal RSSI is intended for diagnostic purposes to set the correct RX path conditions.
The Internal RSSI values can be used to adjust the RX gain settings or decide which RX path (Main or
Auxiliary) provides the greater amplitude and hence to decide if the MUX may need to be reprogrammed
to swap the RX input signal. The measuring system latches the peak value, so the RSSI level can be read
after the end of each receive packet. The RSSI register values are reset with every transmission (TX) by
the reader. This guarantees an updated RSSI measurement for each new tag response.
The Internal RSSI has 7 steps (3 bit) with a typical increment of approximately 4 dB. The operating range
is between 600 mVPP and 4.2 VPP with a typical step size of approximately 600 mV. Both Internal Main
and Internal Auxiliary RSSI values are stored in the RSSI Levels and Oscillator Status register (0x0F). The
nominal relationship between the input RF peak level and the RSSI value is shown in Figure 5-2.
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7
6
5
4
3
2
1
0
0
0.25 0.5 0.75
1
1.25 1.5 1.75
2
2.25 2.5 2.75
3
3.25 3.5 3.75
4
4.25
Input RF Carrier Level in VPP [V]
Figure 5-2. Digital Internal RSSI (Main and Auxiliary) Value vs RF Input Level in VPP (V)
This RSSI measurement is done during the communication to the Tag; this means the TX must be on.
Bit1 in the Chip Status Control Register (0x00) defines if Internal RSSI or the External RSSI value is
stored in the RSSI Levels and Oscillator Status Register 0x0F. Direct command 0x18 is used to trigger an
Internal RSSI measurement.
5.4.1.2 External RSSI
The External RSSI is mainly used for test and diagnostic to sense the amplitude of any 13.56-MHz signal
at the receivers RX_IN1 input. The External RSSI measurement is typically done in active mode when the
receiver is on but transmitter output is off. The level of the RF signal received at the antenna is measured
and stored in the RSSI Levels and Oscillator Status register 0x0F. The relationship between the voltage at
the RX_IN1 input and the 3-bit code is shown in Figure 5-3.
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7
6
5
4
3
2
1
0
0
25
50
75
100
125
150
175
200
225
250
275
300
325
RF Input Voltage Level at RF_IN1 in mVPP
Figure 5-3. Digital External RSSI Value vs RF Input Level in VPP (mV)
The relation between the 3-bit code and the external RF field strength (A/m) sensed by the antenna must
be determined by calculation or by experiments for each antenna design. The antenna Q-factor and
connection to the RF input influence the result. Direct command 0x19 is used to trigger an Internal RSSI
measurement.
For clarity, to check the internal or external RSSI value independent of any other operation, the user must:
•
•
•
Set transmitter to desired state (on or off) using Bit 5 of Chip Status Control Register (0x00)
Set the receiver using direct command 0x17.
Check internal or external RSSI using direct commands 0x18 or 0x19, respectively. This action places
the RSSI value in the RSSI register
•
•
Read the RSSI register using direct command 0x0F; values range from 0x40 to 0x7F.
Repeat steps 1-4 as desired, as register is reset after it is read.
5.5 Oscillator Section
The 13.56-MHz or 27.12-MHz crystal (or oscillator) is controlled by the Chip Status Control Register
(0x00) and the EN and EN2 terminals. The oscillator generates the RF frequency for the RF output stage
as well as the clock source for the digital section. The buffered clock signal is available at pin 27
(SYS_CLK) for any other external circuits. B4 and B5 inside the Modulation and SYS_CLK Register
(0x09) can be used to divide the external SYS_CLK signal at pin 27 by 1, 2 or 4.
Typical start-up time from complete power down is in the range of 3.5 ms.
During Power Down Mode 2 (EN = 0, EN2 = 1) the frequency of SYS_CLK is switched to 60 kHz (typical).
The crystal needs to be connected between pin 31 and pin 32. The external shunt capacitors values for C1
and C2 must be calculated based on the specified load capacitance of the crystal being used. The external
shunt capacitors are calculated as two identical capacitors in series plus the stray capacitance of the
TRF7964A and parasitic PCB capacitance in parallel to the crystal.
The parasitic capacitance (CS, stray and parasitic PCB capacitance) can be estimated at 4 to 5 pF
(typical).
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As an example, using a crystal with a required load capacitance (CL) of 18 pF, the calculation is shown in
Equation 1.
C1 = C2 = 2 × (CL– CS) = 2 × (18 pF – 4.5 pF) = 27 pF
(1)
A 27-pF capacitor must be placed on pins 30 and 31 to ensure proper crystal oscillator operation.
CS
TRF7964A
C1 = C2 = 2 × (CL – CS) = 2 × (18 pF – 4.5 pF) = 27 pF
Pin 31
Pin 32
A 27-pF capacitor needs to be placed on pins 30 and 31
to ensure proper crystal oscillator operation.
Crystal
C1
C2
Figure 5-4. Crystal Block Diagram
Any crystal used with TRF7964A should have minimum characteristics shown in Table 5-7.
Table 5-7. Minimum Crystal Requirements
Parameter
Frequency
Specification
13.56 MHz or 27.12 MHz
Fundamental
Parallel
Mode of Operation
Type of Resonance
Frequency Tolerance
Aging
±20 ppm
< 5 ppm/year
-40°C to 85°C
50 Ω
Operation Temperature Range
Equivalent Series Resistance
As an alternative, an external clock oscillator source can be connected to Pin 31 to provide the system
clock; pin 32 can be left open.
5.6 Transmitter – Analog Section
The 13.56-MHz oscillator generates the RF signal for the PA stage. The power amplifier consists of a
driver with selectable output resistance of nominal 4 Ω or 8 Ω. The transmit power level is set by bit B4 in
the Chip Status Control Register (0x00). The transmit power levels are selectable between 100 mW (half
power) or 200 mW (full power) when configured for 5-V automatic operation. The transmit power levels
are selectable between 33 mW (half power) or 70 mW (full power) when configured for 3-V automatic
operation.
The ASK modulation depth is controlled by bits B0, B1, and B2 in the Modulator and SYS_CLK Control
Register (0x09). The ASK modulation depth range can be adjusted between 7% to 30% or 100% (OOK).
External control of the transmit modulation depth is possible by setting the ISO Control Register (0x01) to
direct mode. While operating the TRF7964A in direct mode, the transmit modulation is made possible by
selecting the modulation type ASK or OOK at pin 12. External control of the modulation type is made
possible only if enabled by setting B6 in the Modulator and SYS_CLK Control Register (0x09) to 1.
In normal operation mode, the length of the modulation pulse is defined by the protocol selected in the
ISO Control Register (0x01). With a high-Q antenna, the modulation pulse is typically prolonged, and the
tag detects a longer pulse than intended. For such cases, the modulation pulse length needs to be
corrected by using the TX Pulse Length Register (0x05).
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If the register contains all zeros, then the pulse length is governed by the protocol selection. If the register
contains a value other than 0x00, the pulse length is equal to the value of the register multiplied by
73.7 ns; therefore, the pulse length can be adjusted between 73.7 ns and 18.8 s in 73.7-ns increments.
5.7 Transmitter – Digital Section
The digital part of the transmitter is a mirror of the receiver. The settings controlled the ISO Control
Register (0x01) are applied to the transmitter just like the receiver. In the TRF7964A default mode the
TRF7964A automatically adds these special signals: start of communication, end of communication, SOF,
EOF, parity bits, and CRC bytes.
The data is then coded to modulation pulse levels and sent to the RF output stage modulation control unit.
Similar to working with the receiver, this means that the external system MCU only has to load the FIFO
with data and all the microcoding is done automatically, again saving the firmware developer code space
and time. Additionally, all of the registers used for transmit parameter control are automatically preset to
optimum values when a new selection is entered into the ISO Control register (0x01).
Note: FIFO must be reset before starting any transmission with Direct Command 0x0F.
There are two ways to start the transmit operation:
•
•
Load the number of bytes to be sent into registers 0x1D and 0x1E and load the data to be sent into the
FIFO (address 0x1F), followed by sending a transmit command (see Direct Commands section). The
transmission then starts when the transmit command is received.
Send the transmit command and the number of bytes to be transmitted first, and then start to send the
data to the FIFO. The transmission starts when first data byte is written into the FIFO.
NOTE
If the data length is longer than the FIFO, the TRF7964A notifies the external system MCU
when most of the data from the FIFO has been transmitted by sending an interrupt request
with a flag in the IRQ register to indicate a FIFO low or high status. The external system
should respond by loading the next data packet into the FIFO.
At the end of a transmit operation, the external system MCU is notified by interrupt request (IRQ) with a
flag in IRQ Register (0x0C) indicating TX is complete (example value = 0x80).
The TX Length registers also support incomplete byte transmission. The high two nibbles in register 0x1D
and the nibble composed of bits B4 through B7 in register 0x1E store the number of complete bytes to be
transmitted. Bit B0 in register 0x1E is a flag indicating that there are also additional bits to be transmitted
that do not form a complete byte. The number of bits is stored in bits B1 through B3 of the same register
(0x1E).
Some protocols have options, and there are two sublevel configuration registers to select the TX protocol
options.
•
ISO14443B TX Options register (0x02). This register controls the SOF and EOF selection and EGT
selection for the ISO14443B protocol.
•
ISO14443A High Bit Rate Options and Parity register (0x03). This register enables the use of different
bit rates for RX and TX operations in the ISO14443 high bit rate protocol and also selects the parity
method in the ISO14443A high bit rate protocol.
The digital section also has a timer. The timer can be used to start the transmit operation at a specified
time in accordance with a selected event.
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5.8 Transmitter – External Power Amplifier and Subcarrier Detector
The TRF7964A can be used in conjunction with an external TX power amplifier or external subcarrier
detector for the receiver path. In this case, certain registers must be programmed as shown here:
•
Bit B6 of the Regulator and I/O Control Register (0x0B) must be set to 1. This setting has two
functions: first, to provide a modulated signal for the transmitter if needed, and second, to configure the
TRF7964A receiver inputs for an external demodulated subcarrier input.
•
Bit B3 of the Modulation and SYS_CLK Control Register (0x09) must be set to 1 (see Section 6.3.2.8).
This function configures the ASK/OOK pin for either a digital or analog output (B3 = 0 enables a digital
output, B3 = 1 enables an analog output). The design of an external power amplifier requires detailed
RF knowledge. There are also readily designed and certified high-power HF reader modules on the
market.
5.9 TRF7964A IC Communication Interface
5.9.1 General Introduction
The communication interface to the reader can be configured in two ways: with a eight line parallel
interface (D0:D7) plus DATA_CLK, or with a three or four wire Serial Peripheral Interface (SPI). The SPI
interface uses traditional Master Out/Slave In (MOSI), Master In/Slave Out (MISO), IRQ, and DATA_CLK
lines. The SPI can be operated with or without using the Slave Select line.
These communication modes are mutually exclusive; that is, only one mode can be used at a time in the
application.
When the SPI interface is selected, the unused I/O_2, I/O_1, and I/O_0 pins must be hard-wired as shown
in Table 5-8. At power up, the TRF7964A samples the status of these three pins and then enters one of
the possible SPI modes.
The TRF7964A always behaves as the slave device, and the microcontroller (MCU) behaves as the
master device. The MCU initiates all communications with the TRF7964A, and the TRF7964A makes use
of the Interrupt Request (IRQ) pin in both parallel and SPI modes to prompt the MCU for servicing
attention.
Table 5-8. Pin Assignment in Parallel and Serial Interface Connection or Direct Mode
Pin
DATA_ CLK
I/O_7
Parallel
DATA_CLK
A/D[7]
Parallel (Direct Mode)
DATA_CLK
SPI With SS
DATA_CLK from master
MOSI(1) = data in (reader in)
SPI Without SS
DATA_CLK from master
MOSI(1) = data in (reader in)
(not used)
Direct mode, data out (subcarrier
or bit stream)
I/O_6
A/D[6]
A/D[5]
MISO(2) = data out (MCU out)
MISO(2) = data out (MCU out)
Direct mode, strobe – bit clock
out
I/O_5(3)
See
See
(3)
(3)
I/O_4
I/O_3
I/O_2
I/O_1
I/O_0
IRQ
A/D[4]
A/D[3]
(not used)
(not used)
(not used)
(not used)
(not used)
IRQ interrupt
SS – slave select(4)
(not used)
At VDD
(not used)
(not used)
At VDD
A/D[2]
A/D[1]
At VDD
At VSS
A/D[0]
At VSS
At VSS
IRQ interrupt
IRQ interrupt
IRQ interrupt
(1) MOSI = Master Out, Slave In
(2) MISO = Master In, Slave Out
(3) I/O_5 pin is used only for information when data is put out of the chip (for example, reading 1 byte from the chip). It is necessary first to
write in the address of the register (8 clocks) and then to generate another 8 clocks for reading out the data. The I/O_5 pin goes high
during the second 8 clocks. But for normal SPI operations, I/O_5 pin is not used.
(4) Slave_Select pin is active low
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Communication is initialized by
a
start condition, which is expected to be followed by an
Address/Command word (Adr/Cmd). The Adr/Cmd word is 8 bits long, and its format is shown in Table 5-
9.
Table 5-9. Address/Command Word Bit Distribution
Bit
Description
Bit Function
Address
Command
0 = address
1 = command
B7
Command control bit
0
1
0 = write
1 = read
B6
Read/Write
R/W
0
B5
B4
B3
B2
B1
B0
Continuous address mode
Address/Command bit 4
Address/Command bit 3
Address/Command bit 2
Address/Command bit 1
Address/Command bit 0
1 = Continuous mode
R/W
Adr 4
Adr 3
Adr 2
Adr 1
Adr 0
0
Cmd 4
Cmd 3
Cmd 2
Cmd 1
Cmd 0
The MSB (bit 7) determines if the word is to be used as a command or as an address. The last two
columns of Table 5-9 show the function of the separate bits if either address or command is written. Data
is expected once the address word is sent. In continuous-address mode (Cont. mode = 1), the first data
that follows the address is written (or read) to (from) the given address. For each additional data, the
address is incremented by one. Continuous mode can be used to write to a block of control registers in a
single stream without changing the address; for example, setup of the predefined standard control
registers from the MCU non-volatile memory to the reader. In non-continuous address mode (simple
addressed mode), only one data word is expected after the address.
Address Mode is used to write or read the configuration registers or the FIFO. When writing more than 12
bytes to the FIFO, the Continuous Address Mode should be set to 1.
The Command Mode is used to enter a command resulting in reader action (for example, initialize
transmission, enable reader, and turn reader on or off).
Examples of expected communications between an MCU and the TRF7964A are shown in the following
sections.
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5.9.1.1 Continuous Address Mode
Table 5-10. Continuous Address Mode
Start
Adr x
Data(x)
Data(x+1)
Data(x+2)
Data(x+3)
Data(x+4)
...
Data(x+n)
StopCont
Figure 5-5. Continuous Address Register Write Example Starting with Register 0x00 Using SPI With SS
Figure 5-6. Continuous Address Register Read Example Starting with Register 0x00 Using SPI With SS
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5.9.1.2 Noncontinuous Address Mode (Single Address Mode)
Table 5-11. Noncontinuous Address Mode (Single Address Mode)
Start
Adr x
Data(x)
Adr y
Data(y)
...
Adr z
Data(z)
StopSgl
Figure 5-7. Single Address Register Write Example of Register 0x00 Using SPI With SS
Figure 5-8. Single Address Register Read Example of Register 0x00 Using SPI With SS
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5.9.1.3 Direct Command Mode
Table 5-12. Direct Command Mode
Start
Cmd x
(Optional data or command)
Stop
Figure 5-9. Direct Command Example of Sending 0x0F (Reset) Using SPI With SS
The other Direct Command Codes from MCU to TRF7964A IC are described in Section 5.11.
5.9.1.4 FIFO Operation
The FIFO is a 128-byte register at address 0x1F with byte storage locations 0 to 127. FIFO data is loaded
in a cyclical manner and can be cleared by a reset command (0x0F) (see Figure 5-9 showing this Direct
Command).
Associated with the FIFO are two counters and three FIFO status flags. The first counter is a 7-bit FIFO
byte counter (bits B0 to B6 in register 0x1C) that tracks the number of bytes loaded into the FIFO. If the
number of bytes in the FIFO is n, the register value is n (number of bytes in FIFO register). For example, if
8 bytes are in the FIFO, the FIFO counter (Register 0x1C) has the hexadecimal value of 0x08 (binary
value of 00001000).
A second counter (12 bits wide) indicates the number of bytes being transmitted (registers 0x1D and
0x1E) in a data frame. An extension to the transmission-byte counter is a 4-bit broken-byte counter also
provided in register 0x1E (bits B0 to B3). Together these counters make up the TX length value that
determines when the reader generates the EOF byte.
FIFO status flags are as follows:
•
FIFO overflow (bit B7 of register 0x1C) – indicates that the FIFO has more than 128 bytes loaded
During transmission, the FIFO is checked for an almost-empty condition, and during reception for an
almost-full condition. The maximum number of bytes that can be loaded into the FIFO in a single
sequence is 128 bytes.
NOTE
The number of bytes in a frame, transmitted or received, can be greater than 128 bytes.
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During transmission, the MCU loads the TRF7964A IC's FIFO (or during reception the MCU removes data
from the FIFO), and the FIFO counter counts the number of bytes being loaded into the FIFO. Meanwhile,
the byte counter keeps track of the number of bytes being transmitted. An interrupt request is generated if
the number of bytes in the FIFO is less than 32 or greater than 96, so that MCU can send new data or
remove the data as necessary. The MCU also checks the number of data bytes to be sent, so as to not
surpass the value defined in TX length bytes. The MCU also signals the transmit logic when the last byte
of data is sent or was removed from the FIFO during reception. Transmission starts automatically after the
first byte is written into FIFO.
Figure 5-10. Example of Checking the FIFO Status Register Using SPI With SS
5.9.2 Parallel Interface Mode
In parallel mode, the start condition is generated on the rising edge of the I/O_7 pin while the CLK is high.
This is used to reset the interface logic. Figure 5-11 shows the sequence of the data, with an 8-bit address
word first, followed by data.
Communication is ended by:
•
•
The StopSmpl condition, where a falling edge on the I/O_7 pin is expected while CLK is high.
The StopCont condition, where the I/O_7 pin must have a successive rising and falling edge while CLK
is low to reset the parallel interface and be ready for the new communication sequence.
•
The StopSmpl condition is also used to terminate the direct mode.
Figure 5-11. Parallel Interface Communication With Simple Stop Condition (StopSmpl)
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Figure 5-12. Parallel Interface Communication with Continuous Stop Condition (StopCont)
Figure 5-13. Example of Parallel Interface Communication with Continuous Stop Condition
5.9.3 Reception of Air Interface Data
At the start of a receive operation (when SOF is successfully detected), B6 is set in the IRQ Status
register. An interrupt request is sent to the MCU at the end of the receive operation if the receive data
string was shorter than or equal to 8 bytes. The MCU receives the interrupt request, then checks to
determine the reason for the interrupt by reading the IRQ Status register (0x0C), after which the MCU
reads the data from the FIFO.
If the received packet is longer than 96 bytes, the interrupt is sent before the end of the receive operation
when the 96th byte is loaded into the FIFO (75% full). The MCU should again read the content of the IRQ
Status register to determine the cause of the interrupt request. If the FIFO is 75% full (as marked with flag
B5 in IRQ Status register and by reading the FIFO Status register), the MCU should respond by reading
the data from FIFO to make room for new incoming receive data. When the receive operation is finished,
the interrupt is sent and the MCU must check how many words are still present in the FIFO before it
finishes reading.
If the reader detects a receive error, the corresponding error flag is set (framing error, CRC error) in the
IRQ Status register, indicating to the MCU that reception was not completed correctly.
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5.9.4 Data Transmission to MCU
Before beginning data transmission, the FIFO should always be cleared with a reset command (0x0F).
Data transmission is initiated with a selected command (see Section 5.11). The MCU then commands the
reader to do a continuous write command (0x3D) starting from register 0x1D. Data written into register
0x1D is the TX Length Byte1 (upper and middle nibbles), while the following byte in register 0x1E is the
TX Length Byte2 (lower nibble and broken byte length) (see Table 6-29 and Table 6-30) . Note that the TX
byte length determines when the reader sends the end of frame (EOF) byte. After the TX length bytes are
written, FIFO data is loaded in register 0x1F with byte storage locations 0 to 127. Data transmission
begins automatically after the first byte is written into the FIFO. The loading of TX length bytes and the
FIFO can be done with a continuous-write command, as the addresses are sequential.
At the start of transmission, the flag B7 (IRQ_TX) is set in the IRQ Status register, and at the end of the
transmit operation, an interrupt is sent to inform the MCU that the task is complete.
5.9.5 Serial Interface Communication (SPI)
When an SPI interface is used, I/O pins I/O_2, I/O_1, and I/O_0 must be hard wired according to Table 5-
8. On power up, the TRF7964A looks for the status of these pins and then enters into one of two possible
SPI modes:
•
•
SPI with Slave Select
SPI without Slave Select
The choice of one of these modes over another should be predicated by the available GPIOs and the
desired control of the system.
The serial communications work in the same manner as the parallel communications with respect to the
FIFO, except for the following condition. On receiving an IRQ from the reader, the MCU reads the
TRF7964A IRQ Status register to determine how to service the reader. After this, the MCU must to do a
dummy read to clear the reader's IRQ status register. The dummy read is required in SPI mode because
the reader's IRQ status register needs an additional clock cycle to clear the register. This is not required in
parallel mode because the additional clock cycle is included in the Stop condition. When first establishing
communications with the TRF7964A, the SOFT_INIT (0x03) command should be sent first from the MCU
(see Table 5-13).
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The procedure for a dummy read is as follows:
1. Start the dummy read:
(a) When using slave select (SS): set SS bit low.
(b) When not using SS: start condition is when Data Clock is high (see Table 5-8).
2. Send address word to IRQ status register (0x0C) with read and continuous address mode bits set to 1
(see Table 5-8).
3. Read 1 byte (8 bits) from IRQ status register (0x0C).
4. Dummy-read 1 byte from register 0x0D (collision position and interrupt mask).
5. Stop the dummy read:
(a) When using slave select (SS): set SS bit high.
(b) When not using SS: stop condition when Data Clock is high.
Write Address
Byte (0x6C)
Read Data in
IRQ Status Register
Dummy Read
DATA
CLK
0
1
1
0
1
1
0
0
MOSI
MISO
No Data Transitions (All High/Low) No Data Transitions (All High/Low)
Ignore
Don't Care
B7 B6 B5 B4 B3 B2 B1 B0
SLAVE
SELECT
Figure 5-14. Procedure for Dummy Read
Figure 5-15. Example of Dummy Read Using SPI With SS
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5.9.5.1 Serial Interface Mode Without Slave Select (SS)
The serial interface without the slave select pin must use delimiters for the start and stop conditions.
Between these delimiters, the address, data, and command words can be transferred. All words must be 8
bits long with MSB transmitted first.
Start
Condition
Stop
Condition
Data_Clock
50 ns
b7
Data In
b6
b5
b4
b3
b2
b1
b0
Data Out
Figure 5-16. SPI Without Slave Select Timing Diagram
In this mode, a rising edge on data-in (I/O_7, pin 24) while SCLK is high resets the serial interface and
prepares it to receive data. Data-in can change only when SCLK is low and is taken by the reader on the
SCLK rising edge. Communication is terminated by the stop condition when the data-in falling edge occurs
during a high SCLK period.
5.9.5.2 Serial Interface Mode With Slave Select (SS)
The serial interface is in reset while the Slave Select signal is high. Serial data in (MOSI) changes on the
falling edge, and is validated in the reader on the rising edge, as shown in Figure 5-17. Communication is
terminated when the Slave Select signal goes high.
All words must be 8 bits long with the MSB transmitted first.
WRITE MODE
CKPH = 0, CKPL=0
Data Transition is on
READ MODE
CKPH = 0, CKPL=0
Data Transition is on
tSTE,LA
G
tSTE,LA
G
tSTE,LEAD
Data Clock rising edge
MOSI Valid on Data Clock Falling Edge
Data Clock rising edge
MISO Valid on Data Clock Falling Edge
1/fUCxCLK
DATA
CLK
tHD,SI
tSU,SO
tLO/HI
tLO/HI
tSU,SI
NO DATA TRANSITIONS
(ALL HIGH/LOW)
MOSI
MISO
b7
b6...b1
b0
tHD,SO
tVALID,SO
tSTE,DIS
DON’T CARE
b7
b6...
...b1
b0
Figure 5-17. SPI With Slave Select Timing Diagram
The read command is sent out on the MOSI pin, MSB first, in the first eight clock cycles. MOSI data
changes on the falling edge, and is validated in the reader on the rising edge, as shown in Figure 5-17.
During the write cycle, the serial data out (MISO) is not valid. After the last read command bit (B0) is
validated at the eighth rising edge of SCLK, after half a clock cycle, valid data can be read on the MISO
pin at the falling edge of SCLK. It takes eight clock edges to read out the full byte (MSB first). See
Section 3.4 for electrical specifications related to Figure 5-17.
The continuous read operation is shown in Figure 5-18.
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Write
Address Byte
Read
Data Byte 1
Read
Data Byte n
DATA_CLK
MOSI
No Data Transitions
(All High/Low)
No Data Transitions
(All High/Low)
B7 B6 B5 B4 B3 B2 B1 B0
B7 B6 B5 B4 B3 B2 B1 B0
MISO
Don't Care
B7 B6 B5 B4 B3 B2 B1 B0
SLAVE
SELECT
Figure 5-18. Continuous Read Operation Using SPI With Slave Select
Figure 5-19. Continuous Read of Registers 0x00 Through 0x05 Using SPI With SS
Performing Single Slot Inventory Command as an example is shown in Figure 5-20. Reader registers (in
this example) are configured for 5 VDC in and default operation. For full sequences for other settings and
protocols can be found here: http://www.ti.com/lit/zip/sloc240
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Figure 5-20. Inventory Command Sent From MCU to TRF7964A
The TRF7964A takes these bytes from the MCU and then send out Request Flags, Inventory Command
,and Mask over the air to the ISO15693 transponder. After these three bytes have been transmitted, an
interrupt occurs to indicate back to the reader that the transmission has been completed. In the example in
Figure 5-21, this IRQ occurs approximately 1.6 ms after the SS line goes high after the Inventory
command is sent out.
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Figure 5-21. IRQ After Inventory Command
The IRQ status register read (0x6C) yields 0x80, which indicates that TX is indeed complete. This is
followed by dummy clock and reset of FIFO with dummy clock. Then, if a tag is in the field and no error is
detected by the reader, a second interrupt is expected and occurs (in this example) approximately 4 ms
after first IRQ is read and cleared.
In the continuation of the example (see Figure 5-22), the IRQ Status Register is read using method
previously recommended, followed by a single read of the FIFO status register, which indicates that there
are at least 9 bytes to be read out.
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Figure 5-22. Read IRQ Status Register After Inventory Command
This is then followed by a continuous read of the FIFO. The first byte is (and should be) 0x00 for no error.
The next byte is the DSFID (usually shipped by manufacturer as 0x00), then the UID, shown here up to
the next most significant byte, the MFG code (shown as 0x07 (TI silicon)).
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Figure 5-23. Continuous Read of FIFO After Inventory Command
This is followed by another IRQ approximately 160 µs later, as there is still one byte in FIFO, the MSB of
the UID, which must be retrieved. IRQ register read shows RX is complete and FIFO register status shows
one byte available, as expected and it is the E0, indicating ISO15693 transponder.
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Figure 5-24. Second IRQ After Inventory Command
At this point it is good form to reset the FIFO and then read out the RSSI value of the tag. In this case the
transponder is very close to the antenna, so value of 0x7E is recovered.
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Figure 5-25. Reset FIFO and Read RSSI
5.9.6 Direct Mode
Direct mode allows the user to configure the reader in one of two ways. Direct Mode 0 (bit 6 = 0, as
defined in ISO Control register) allows the user to use only the front-end functions of the reader,
bypassing the protocol implementation in the reader. For transmit functions, the user has direct access to
the transmit modulator through the MOD pin (pin 14). On the receive side, the user has direct access to
the subcarrier signal (digitized RF envelope signal) on I/O_6 (pin 23).
Direct Mode 1 (bit 6 = 1, as defined in ISO Control register) uses the subcarrier signal decoder of the
selected protocol (as defined in ISO Control register). This means that the receive output is not the
subcarrier signal but the decoded serial bit stream and bit clock signals. The serial data is available on
I/O_6 (pin 23) and the bit clock is available on I/O_5 (pin 22). The transmit side is identical; the user has
direct control over the RF modulation through the MOD input. This mode is provided so that the user can
implement a protocol that has the same bit coding as one of the protocols implemented in the reader, but
needs a different framing format.
To select direct mode, the user must first choose which direct mode to enter by writing B6 in the ISO
Control register. This bit determines if the receive output is the direct subcarrier signal (B6 = 0) or the
serial data of the selected decoder. If B6 = 1, then the user must also define which protocol should be
used for bit decoding by writing the appropriate setting in the ISO Control register.
The reader actually enters the direct mode when B6 (direct) is set to 1 in the chip status control register.
Direct mode starts immediately. The write command should not be terminated with a stop condition (see
communication protocol), because the stop condition terminates the direct mode and clears B6. This is
necessary as the direct mode uses one or two I/O pins (I/O_6, I/O_5). Normal parallel communication is
not possible in direct mode. Sending a stop condition terminates direct mode.
Figure 5-26 shows the different configurations available in direct mode.
•
•
In mode 0, the reader is used as an AFE only, and protocol handling is bypassed.
In mode 1, framing is not done, but SOF and EOF are present. This allows for a user-selectable
framing level based on an existing ISO standard.
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•
In mode 2, data is ISO-standard formatted. SOF, EOF, and error checking are removed, so the
microprocessor receives only bytes of raw data through a 128-byte FIFO.
Analog Front End (AFE)
Direct Mode 0:
Raw RF Sub-Carrier
Data Stream
ISO Encoders/Decoders
14443A
14443B
15693
FeliCa
Direct Mode 1:
Raw Digital ISO Coded
Data Without
Protocol Frame
Packetization/Framing
Microcontroller
ISO Mode:
Full ISO Framing
and Error Checking
(Typical Mode)
Figure 5-26. User-Configurable Modes
The steps to enter Direct Mode are listed below, using SPI with SS communication method only as one
example, as Direct Modes are also possible with parallel and SPI without SS. The must enter Direct Mode
0 to accommodate non-ISO standard compliant card type communications. Direct Mode can be entered at
any time, so in the event a card type started with ISO standard communications, then deviated from the
standard after being identified and selected, the ability to go into Direct Mode 0 becomes very useful.
Step 1: Configure Pins I/O_0 to I/O_2 for SPI with SS
Step 2: Set Pin 12 of the TRF7964A (ASK/OOK pin) to 0 for ASK or 1 for OOK
Step 3: Program the TRF7964A registers
The following registers need to be explicitly set before going into the Direct Mode.
1. ISO Control register (0x01) to the appropriate standard
–
–
–
–
0x02 for ISO 15693 High Data Rate (26.48 kbps)
0x08 for ISO14443A (106 kbps)
0x1A for FeliCa 212 kbps
0x1B for FeliCa 424 kbps
2. Modulator and SYS_CLK Register (0x09) to the appropriate clock speed and modulation
–
–
–
–
–
–
0x21 for 6.78 MHz Clock and OOK (100%) modulation
0x20 for 6.78 MHz Clock and ASK 10% modulation
0x22 for 6.78 MHz Clock and ASK 7% modulation
0x23 for 6.78 MHz Clock and ASK 8.5% modulation
0x24 for 6.78 MHz Clock and ASK 13% modulation
0x25 for 6.78 MHz Clock and ASK 16% modulation
(See register 0x09 definition for all other possible values)
Example register setting for ISO14443A at 106 kbps:
•
•
•
•
•
ISO Control register (0x01) to 0x08
RX No Response Wait Time register (0x07) to 0x0E
RX Wait Time register (0x08) to 0x07
Modulator control register (0x09) to 0x21 (or any custom modulation)
RX Special Settings register (0x0A) to 0x20
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Step 4: Entering Direct Mode 0
The following registers need to be programmed to enter Direct Mode 0
1. Set bit B6 of the Modulator and SYS_CLK Control register (0x09) to 1.
2. Set bit B6 of the ISO Control (Register 01) to 0 for Direct Mode 0 (default its 0)
3. Set bit B6 of the Chip Status Control register (0x00) to 1 to enter Direct Mode
4. Send extra eight clock cycles (see Figure 5-27, this step is TRF7964A specific)
NOTE
–
–
It is important that the last write is not terminated with a stop condition. For SPI, this
means that Slave Select (I/O_4) stays low.
Sending a Stop condition terminates the Direct Mode and clears bit B6 in the Chip Status
Control register (0x00).
NOTE
Access to Registers, FIFO, and IRQ is not available during Direct Mode 0.
The reader enters the Direct Mode 0 when bit 6 of the Chip Status Control register (0x00) is set to a 1 and
stays in Direct Mode 0 until a stop condition is sent from the microcontroller.
NOTE
The write command should not be terminated with a stop condition (for example, in SPI
mode this is done by bringing the Slave Select line high after the register write), because the
stop condition terminates the direct mode and clears bit 6 of the Chip Status Control Register
(0x00), making it a 0.
Figure 5-27. Entering Direct Mode 0
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Step 5: Transmit Data Using Direct Mode
The application now has direct control over the RF modulation through the MOD input (see Figure 5-28).
TRF7964A
Microcontroller
Drive the MOD pin
according to the data coding
specified by the standard
MOD
(Pin 14)
Decode the subcarrier
information according
to the standard
I/O_6
(Pin 23)
Figure 5-28. Direct Control Signals
The microcontroller is responsible for generating data according to the coding specified by the particular
standard. The microcontroller must generate SOF, EOF, Data, and CRC. In direct mode, the FIFO is not
used and no IRQs are generated. See the applicable ISO standard to understand bit and frame
definitions. As an example of what the developer sees when using DM0 in an actual application, Figure 5-
29 is presented to clearly show the relationship between the MOD pin being controlled by the MCU and
the resulting modulated 13.56-MHz carrier signal.
Figure 5-29. TX Sequence Out in DM0
Step 6: Receive Data Using Direct Mode
After the TX operation is complete, the tag responds to the request and the subcarrier data is available on
pin I/O_6. The microcontroller needs to decode the subcarrier signal according to the standard. This
includes decoding the SOF, data bits, CRC, and EOF. The CRC then needs to be checked to verify data
integrity. The receive data bytes must be buffered locally.
As an example of the receive data bits and framing level according to the ISO14443A standard is shown
in Figure 5-30 (taken from ISO14443 specification and TRF7964A air interface).
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?
?
?
128/fc = 9.435 µs = tb (106-kbps data rate)
64/fc = 4.719 µs = tx time
32/fc = 2.359 µs = t1 time
tb = 9.44 µs
tx = 4.72 µs
t1 = 2.48 µs
Sequence Y = Carrier for 9.44 µs
Sequence Z = Pause for 2 to 3 µs,
Carrier for Remainder of 9.44 µs
Figure 5-30. Receive Data Bits and Framing Level
Figure 5-31 is presented to clearly show an example of what the developer should expect on the I/O_6
line during the RX process while in Direct Mode 0.
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Figure 5-31. RX Sequence on I/O_6 in DM0 (Analog Capture)
Step 7: Terminating Direct Mode 0
After the EOF is received, data transmission is over, and Direct Mode 0 can be terminated by sending a
Stop Condition (in the case of SPI, make the Slave Select go high). The TRF7964A is returned to default
state.
5.10 Special Direct Mode for Improved MIFARE Compatibility
See the application report TRF7964A Firmware Design Hints (SLOA159).
5.11 Direct Commands from MCU to Reader
5.11.1 Command Codes
Table 5-13. Address/Command Word Bit Distribution
Command Code
0x00
Command
Comments
Idle
0x03
Software Initialization
Reset
Same as Power on Reset
0x0F
0x10
Transmission without CRC
Transmission with CRC
0x11
0x12
Delayed Transmission without CRC
Delayed Transmission with CRC
End of Frame/Transmit Next Time Slot
Block Receiver
0x13
0x14
ISO15693
0x16
0x17
Enable Receiver
0x18
Test external RF (RSSI at RX input with TX on)
Test internal RF (RSSI at RX input with TX off)
Receiver Gain Adjust
0x19
0x1A
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The command code values from Table 5-13 are substituted in Table 5-14, Bits 0 through 4. Also, the
most-significant bit (MSB) in Table 5-14 must be set to 1. ( Table 5-14 is same as Table 5-9, shown
here again for user clarity).
Table 5-14. Address/Command Word Bit Distribution
Bit
Description
Bit Function
Address
Command
0 = address
1 = command
B7
Command control bit
0
1
0 = write
1 = read
B6
Read/Write
R/W
0
B5
B4
B3
B2
B1
B0
Continuous address mode
Address/Command bit 4
Address/Command bit 3
Address/Command bit 2
Address/Command bit 1
Address/Command bit 0
1 = Continuous mode
R/W
Adr 4
Adr 3
Adr 2
Adr 1
Adr 0
0
Cmd 4
Cmd 3
Cmd 2
Cmd 1
Cmd 0
The MSB determines if the word is to be used as a command or address. The last two columns of
Table 5-14 show the function of each bit, depending on whether address or command is written.
Command mode is used to enter a command resulting in reader action (initialize transmission, enable
reader, and turn reader on or off).
5.11.1.1 Software Initialization (0x03)
This command starts a Power on Reset.
5.11.1.2 Reset (0x0F)
The reset command clears the FIFO contents and FIFO status register (0x1C). It also clears the register
storing the collision error location (0x0E).
5.11.1.3 Transmission With CRC (0x11)
The transmission command must be sent first, followed by transmission length bytes, and FIFO data. The
reader starts transmitting after the first byte is loaded into the FIFO. The CRC byte is included in the
transmitted sequence.
5.11.1.4 Transmission Without CRC (0x10)
Same as Section 5.11.1.3 with CRC excluded.
5.11.1.5 Delayed Transmission With CRC (0x13)
The transmission command must be sent first, followed by the transmission length bytes, and FIFO data.
The reader transmission is triggered by the TX timer.
5.11.1.6 Delayed Transmission Without CRC (0x12)
Same as Section 5.11.1.5 with CRC excluded.
5.11.1.7 Transmit Next Time Slot (0x14)
When this command is received, the reader transmits the next slot command. The next slot sign is defined
by the protocol selection.
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5.11.1.8 Block Receiver (0x16)
The block receiver command puts the digital part of receiver (bit decoder and framer) in reset mode. This
is useful in an extremely noisy environment, where the noise level could otherwise cause a constant
switching of the subcarrier input of the digital part of the receiver. The receiver (if not in reset) would try to
catch a SOF signal, and if the noise pattern matched the SOF pattern, an interrupt would be generated,
falsely signaling the start of an RX operation. A constant flow of interrupt requests can be a problem for
the external system (MCU), so the external system can stop this by putting the receive decoders in reset
mode. The reset mode can be terminated in two ways. The external system can send the enable receiver
command. The reset mode is also automatically terminated at the end of a TX operation. The receiver can
stay in reset after end of TX if the RX wait time register (0x08) is set. In this case, the receiver is enabled
at the end of the wait time following the transmit operation.
5.11.1.9 Enable Receiver (0x17)
This command clears the reset mode in the digital part of the receiver if the reset mode was entered by
the block receiver command.
5.11.1.10 Test Internal RF (RSSI at RX Input With TX ON) (0x18)
The level of the RF carrier at RF_IN1 and RF_IN2 inputs is measured. Operating range between 300 mVP
and 2.1 VP (step size is 300 mV). The two values are displayed in the RSSI levels register (0x0F). The
command is intended for diagnostic purposes to set correct RF_IN levels. Optimum RFIN input level is
approximately 1.6 VP or code 5 to 6. The nominal relationship between the RF peak level and RSSI code
is shown in Table 5-15 and in Section 5.4.1.1.
NOTE
If the command is executed immediately after power-up and before any communication with
a tag is performed, the command must be preceded by Enable RX command. The Check RF
commands require full operation, so the receiver must be activated by Enable RX or by a
normal Tag communication for the Check RF command to work properly.
Table 5-15. Test Internal RF Peak Level to RSSI Codes
RF_IN1 [mVPP
Decimal Code
Binary Code
]
300
1
600
2
900
3
1200
4
1500
5
1800
6
2100
7
001
010
011
001
101
011
111
5.11.1.11 Test External RF (RSSI at RX Input with TX OFF) (0x19)
This command can be used in active mode when the RF receiver is switched on but RF output is switched
off. This means bit B1 = 1 in Chip Status Control Register. The level of RF signal received on the antenna
is measured and displayed in the RSSI Levels register (0x0F). The relation between the 3 bit code and the
external RF field strength [A/m] must be determinate by calculation or by experiments for each antenna
type as the antenna Q and connection to the RF input influence the result. The nominal relation between
the RF peak to peak voltage in the RF_IN1 input and RSSI code is shown in Table 5-16 and in
Section 5.4.1.2.
NOTE
If the command is executed immediately after power-up and before any communication with
a tag is performed, the command must be preceded by an Enable RX command. The Check
RF commands require full operation, so the receiver must be activated by Enable RX or by a
normal Tag communication for the Check RF command to work properly.
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Table 5-16. Test External RF Peak Level to RSSI Codes
RF_IN1 [mVPP
Decimal Code
Binary Code
]
40
1
60
2
80
3
100
4
140
5
180
6
300
7
001
010
011
001
101
011
111
5.11.1.12 Receiver Gain Adjust (0x1A)
This command should be executed when the MCU determines that no TAG response is coming and when
the RF and receivers are switched ON. When this command is received, the reader observes the digitized
receiver output. If more than two edges are observed in 100 ms, the window comparator voltage is
increased. The procedure is repeated until the number of edges (changes of logical state) of the digitized
reception signal is less than 2 (in 100 ms). The command can reduce the input sensitivity in 5-dB
increments up to 15 dB. This command ensures better operation in a noisy environment. The gain setting
is reset to maximum gain at EN = 0 and POR = 1.
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6 Register Description
6.1 Register Preset
After power-up and the EN pin low-to-high transition, the reader is in the default mode. The default
configuration is ISO15693, single subcarrier, high data rate, 1-out-of-4 operation. The low-level option
registers (0x02 to 0x0B) are automatically set to adapt the circuitry optimally to the appropriate protocol
parameters. When entering another protocol (by writing to the ISO Control register 0x01), the low-level
option registers (0x02 to 0x0B) are automatically configured to the new protocol parameters. After
selecting the protocol, it is possible to change some low-level register contents if needed. However,
changing to another protocol and then back, reloads the default settings, and so then the custom settings
must be reloaded.
The Clo0 and Clo1 register (0x09) bits, which define the microcontroller frequency available on the
SYS_CLK pin, are the only two bits in the configuration registers that are not cleared during protocol
selection.
6.2 Register Overview
Table 6-1. Register Definitions
Address
Register
Read/Write
Main Control Registers
0x00
Chip Status Control
ISO Control
R/W
R/W
0x01
Protocol Sub-Setting Registers
0x02
0x03
ISO14443B TX options
ISO14443A high bit rate options
TX timer setting, H-byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0x04
0x05
TX timer setting, L-byte
0x06
TX pulse-length control
0x07
RX no response wait
0x08
RX wait time
0x09
Modulator and SYS_CLK control
RX Special Setting
0x0A
0x0B
Regulator and I/O control
Special Function Register, Preset 0x00
Special Function Register, Preset 0x00
Adjustable FIFO IRQ Levels Register
0x10
0x11
0x14
Status Registers
0x0C
IRQ status
R
R/W
R
0x0D
0x0E
Collision position and interrupt mask register
Collision position
Test Registers
0x1A
Test Register. Preset 0x00
Test Register. Preset 0x00
R/W
R/W
0x1B
FIFO Registers
0x1C
FIFO status
TX length byte1
TX length byte2
FIFO I/O register
R
0x1D
R/W
R/W
R/W
0x1E
0x1F
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6.3 Detailed Register Description
6.3.1 Main Configuration Registers
6.3.1.1 Chip Status Control Register (0x00)
Table 6-2. Chip Status Control Register (0x00)
Function: Control of Power mode, RF on/off, AGC, AM/PM, Direct Mode
Default: 0x01, preset at EN = L or POR = H
Bit
Name
Function
1 = Standby Mode
0 = Active Mode
Description
Standby mode keeps all supply regulators, 13.56-MHz SYS_CLK oscillator
running. (typical start-up time to full operation 100 µs)
B7
stby
Active Mode (default)
Provides user direct access to AFE (Direct Mode 0) or allows user to add their
own framing (Direct Mode 1). Bit 6 of ISO Control register must be set by user
before entering Direct Mode 0 or 1.
1 = Direct Mode 0 or 1
B6
B5
B4
direct
rf_on
0 = Direct Mode 2 (default) Uses SPI or parallel communication with automatic framing and ISO decoders
1 = RF output active
Transmitter on, receivers on
Transmitter off
0 = RF output not active
TX_OUT (pin 5) = 8-Ω output impedance P = 100 mW (20 dBm) at 5 V,
P = 33 mW (+15 dBm) at 3.3 V
1 = half output power
0 = full output power
rf_pwr
TX_OUT (pin 5) = 4-Ω output impedance P = 200 mW (+23 dBm) at 5 V,
P = 70 mW (+18 dBm) at 3.3 V
1 = selects Aux RX input
0 = selects Main RX input
1 = AGC on
RX_IN2 input is used
B3
B2
pm_on
agc_on
RX_IN1 input is used
Enables AGC (AGC gain can be set in register 0x0A)
AGC block is disabled
0 = AGC off
1 = Receiver activated for
Forced enabling of receiver and TX oscillator. Used for external field
external field measurement measurement.
B1
B0
rec_on
vrs5_3
0 = Automatic Enable
Allows enable of the receiver by Bit 5 of this register (0x00)
1 = 5 V operation
0 = 3 V operation
Selects the VIN voltage range
6.3.1.2 ISO Control Register (0x01)
Table 6-3. ISO Control Register (0x01)
Function: Controls the selection of ISO Standard protocol, Direct Mode and Receive CRC
Default: 0x02 (ISO15693 high bit rate, one subcarrier, 1 out of 4); it is preset at EN = L or POR = H
Bit
Name
Function
Description
0 = RX CRC (CRC is present in the response)
1 = no RX CRC (CRC is not present in the response)
B7
rx_crc_n
CRC Receive selection
0 = Direct Mode 0
1 = Direct Mode 1
B6
B5
dir_mode
rfid
Direct mode type selection
RFID / Reserved
0 = RFID Mode
1 = Reserved (should be set to 0)
RFID: See Table 6-4 for B0:B4 settings based on ISO protocol desired by
application
B4
B3
B2
B1
iso_4
iso_3
RFID
RFID
RFID
RFID
RFID: See Table 6-4 for B0:B4 settings based on ISO protocol desired by
application
RFID: See Table 6-4 for B0:B4 settings based on ISO protocol desired by
application
iso_2
RFID: See Table 6-4 for B0:B4 settings based on ISO protocol desired by
application
iso_1
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Table 6-3. ISO Control Register (0x01) (continued)
RFID: See Table 6-4 for B0:B4 settings based on ISO protocol desired by
application
B0
iso_0
RFID
Table 6-4. ISO Control Register ISO_x Settings, RFID Mode
ISO_4
ISO_3
ISO_2
ISO_1
ISO_0
Protocol
Remarks
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
ISO15693 low bit rate, 6.62 kbps, one subcarrier, 1 out of 4
ISO15693 low bit rate, 6.62 kbps, one subcarrier, 1 out of 256
ISO15693 high bit rate, 26.48 kbps, one subcarrier, 1 out of 4
ISO15693 high bit rate, 26.48 kbps, one subcarrier, 1 out of 256
ISO15693 low bit rate, 6.67 kbps, double subcarrier, 1 out of 4
ISO15693 low bit rate, 6.67 kbps, double subcarrier, 1 out of 256
ISO15693 high bit rate, 26.69 kbps, double subcarrier, 1 out of 4
Default for reader
ISO15693 high bit rate, 26.69 kbps, double subcarrier,
1 out of 256
0
0
1
1
1
(1)
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
0
0
1
1
0
0
0
0
1
1
1
1
0
1
0
0
0
0
1
1
0
0
1
1
1
0
1
1
0
1
0
1
0
1
0
1
1
0
0
1
ISO14443A RX bit rate, 106 kbps
ISO14443A RX high bit rate, 212 kbps
ISO14443A RX high bit rate, 424 kbps
ISO14443A RX high bit rate, 848 kbps
ISO14443B RX bit rate, 106 kbps
ISO14443B RX high bit rate, 212 kbps
ISO14443B RX high bit rate, 424 kbps
ISO14443B RX high bit rate, 848 kbps
Reserved
RX bit rate
(1)
RX bit rate
Reserved
FeliCa 212 kbps
FeliCa 424 kbps
(1) For ISO14443A/B, when bit rate of TX is different than RX, settings can be done in register 0x02 or 0x03.
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6.3.2 Control Registers – Sub Level Configuration Registers
6.3.2.1 ISO14443B TX Options Register (0x02)
Table 6-5. ISO14443B TX Options Register (0x02)
Function: Selects the ISO subsets for ISO14443B – TX
Default: 0x00 at POR = H or EN = L
Bit
B7
B6
B5
Name
egt2
egt1
egt0
Function
Description
TX EGT time select MSB
TX EGT time select
Three bit code defines the number of etu (0-7) which separate two characters.
ISO14443B TX only
TX EGT time select LSB
1 = EOF→ 0 length 11 etu
0 = EOF→ 0 length 10 etu
B4
B3
B2
eof_l0
sof_l1
sof _l0
1 = SOF→ 1 length 03 etu
0 = SOF→ 1 length 02 etu
ISO14443B TX only
1 = SOF→ 0 length 11 etu
0 = SOF→ 0 length 10 etu
1 = EGT after each byte
0 = EGT after last byte is
omitted
B1
B0
l_egt
Reserved
6.3.2.2 ISO14443A High-Bit-Rate and Parity Options Register (0x03)
Table 6-6. ISO14443A High-Bit-Rate and Parity Options Register (0x03)
Function: Selects the ISO subsets for ISO14443A – TX
Default: 0x00 at POR = H or EN = L, and at each write to ISO Control register
Bit
B7
B6
Name
dif_tx_br
tx_br1
Function
Description
TX bit rate different than RX
bit rate enable
Valid for ISO14443A/B high bit rate
tx_br1 = 0, tx_br = 0 → 106 kbps
tx_br1 = 0, tx_br = 1 → 212 kbps
tx_br1 = 1, tx_br = 0 → 424 kbps
tx_br1 = 1, tx_br = 1 → 848 kbps
TX bit rate
B5
tx_br0
1 = parity odd except last
byte which is even for TX
B4
B3
parity-2tx
parity-2rx
For 14443A high bit rate, coding and decoding
1 = parity odd except last
byte which is even for RX
B2
B1
B0
Unused
Unused
Unused
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6.3.2.3 TX Timer High Byte Control Register (0x04)
Table 6-7. TX Timer High Byte Control Register (0x04)
Function: For Timings
Default: 0xC2 at POR = H or EN = L, and at each write to ISO Control register
Bit
Name
Function
Description
B7
tm_st1
Timer Start Condition
tm_st1 = 0, tm_st0 = 0 → beginning of TX SOF
tm_st1 = 0, tm_st0 = 1 → end of TX SOF
tm_st1 = 1, tm_st0 = 0 → beginning of RX SOF
tm_st1 = 1, tm_st0 = 1 → end of RX SOF
B6
tm_st0
Timer Start Condition
B5
B4
B3
B2
B1
B0
tm_lengthD
tm_lengthC
tm_lengthB
tm_lengthA
tm_length9
tm_length8
Timer Length MSB
Timer Length
Timer Length
Timer Length
Timer Length
Timer Length LSB
6.3.2.4 TX Timer Low Byte Control Register (0x05)
Table 6-8. TX Timer Low Byte Control Register (0x05)
Function: For Timings
Default: 0x00 at POR = H or EN = L, and at each write to ISO Control register
Bit
B7
B6
B5
B4
B3
B2
B1
B0
Name
Function
Timer Length MSB
Timer Length
Description
tm_length7
tm_length6
tm_length5
tm_length4
tm_length3
tm_length2
tm_length1
tm_length0
Defines the time when delayed transmission is started.
RX wait range is 590 ns to 9.76 ms (1 to 16383)
Step size is 590 ns
Timer Length
Timer Length
Timer Length
All bits low = timer disabled (0x00)
Timer Length
Timer Length
Preset 0x00 for all other protocols
Timer Length LSB
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6.3.2.5 TX Pulse Length Control Register (0x06)
The length of the modulation pulse is defined by the protocol selected in the ISO Control register 0x01.
With a high Q antenna, the modulation pulse is typically prolonged, and the tag detects a longer pulse
than intended. For such cases, the modulation pulse length can be corrected by using the TX pulse length
register 0x06. If the register contains all zeros, then the pulse length is governed by the protocol selection.
If the register contains a value other than 0x00, the pulse length is equal to the value of the register in
73.7-ns increments. This means the range of adjustment can be 73.7 ns to 18.8 µs.
Table 6-9. TX Pulse Length Control Register (0x06)
Function: Controls the length of TX pulse
Default: 0x00 at POR = H or EN = L and at each write to ISO Control register.
Bit
B7
B6
B5
B4
B3
B2
B1
Name
Pul_p2
Pul_p1
Pul_p0
Pul_c4
Pul_c3
Pul_c2
Pul_c1
Function
Description
Pulse length MSB
The pulse range is 73.7 ns to 18.8 µs (1….255), step size 73.7 ns.
All bits low (00): pulse length control is disabled.
The following default timings are preset by the ISO Control register (0x01):
9.44 µs → ISO15693 (TI Tag-It HF-I)
11 µs → Reserved
2.36 µs → ISO14443A at 106 kbps
1.4 µs → ISO14443A at 212 kbps
B0
Pul_c0
Pulse length LSB
737 ns → ISO14443A at 424 kbps
442 ns → ISO14443A at 848 kbps; pulse length control disabled
6.3.2.6 RX No Response Wait Time Register (0x07)
The RX No Response timer is controlled by the RX NO Response Wait Time Register 0x07. This timer
measures the time from the start of slot in the anticollision sequence until the start of tag response. If there
is no tag response in the defined time, an interrupt request is sent and a flag is set in IRQ status control
register 0x0C. This enables the external controller to be relieved of the task of detecting empty slots. The
wait time is stored in the register in increments of 37.76 µs. This register is also preset, automatically, for
every new protocol selection.
Table 6-10. RX No Response Wait Time Register (0x07)
Function: Defines the time when "no response" interrupt is sent; only for ISO15693
Default: 0x0E at POR = H or EN = L and at each write to ISO Control register
Bit
B7
B6
B5
B4
B3
B2
B1
Name
Function
Description
NoResp7
NoResp6
NoResp5
NoResp4
NoResp3
NoResp2
NoResp1
No response MSB
Defines the time when "no response" interrupt is sent. It starts from the end of
TX EOF. RX no response wait range is 37.76 µs to 9628 µs (1 to 255), step
size is: 37.76 µs.
The following default timings are preset by the ISO Control register (0x01):
390 µs → Reserved
529 µs → for all protocols supported, but not listed here
604 µs → Reserved
755 µs → ISO15693 high data rate (TI Tag-It HF-I)
1812 µs → ISO15693 low data rate (TI Tag-It HF-I)
B0
NoResp0
No response LSB
56
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6.3.2.7 RX Wait Time Register (0x08)
The RX-wait-time timer is controlled by the value in the RX wait time register 0x08. This timer defines the
time after the end of the transmit operation in which the receive decoders are not active (held in reset
state). This prevents incorrect detections resulting from transients following the transmit operation. The
value of the RX wait time register defines this time in increments of 9.44 µs. This register is preset at
every write to ISO Control register 0x01 according to the minimum tag response time defined by each
standard.
Table 6-11. RX Wait Time Register (0x08)
Function: Defines the time after TX EOF when the RX input is disregarded for example, to block out electromagnetic disturbance
generated by the responding card.
Default: 0x1F at POR = H or EN = L and at each write toISO control register.
Bit
B7
B6
B5
B4
B3
B2
B1
Name
Rxw7
Rxw6
Rxw5
Rxw4
Rxw3
Rxw2
Rxw1
Function
Description
Defines the time after the TX EOF during which the RX input is ignored. Time
starts from the end of TX EOF.
RX wait range is 9.44 µs to 2407 µs (1 to 255), Step size 9.44 µs.
The following default timings are preset by the ISO Control register (0x01):
9.44 µs → FeliCa
RX wait time
66 µs → ISO14443A and B
180 µs → Reserved
B1
Rxw0
293 µs → ISO15693 (TI Tag-It HF-I)
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6.3.2.8 Modulator and SYS_CLK Control Register (0x09)
The frequency of SYS_CLK (pin 27) is programmable by the bits B4 and B5 of this register. The frequency
of the TRF7964A system clock oscillator is divided by 1, 2 or 4 resulting in available SYS_CLK
frequencies of 13.56 MHz or 6.78 MHz or 3.39 MHz.
The ASK modulation depth is controlled by bits B0, B1 and B2. The range of ASK modulation is 7% to
30% or 100% (OOK). The selection between ASK and OOK (100%) modulation can also be done using
direct input OOK (pin 12). The direct control of OOK/ASK using OOK pin is only possible if the function is
enabled by setting B6 = 1 (en_ook_p) in this register (0x09) and the ISO Control Register (0x01, B6 = 1).
When configured this way, the MOD (pin 14) is used as input for the modulation signal.
Table 6-12. Modulator and SYS_CLK Control Register (0x09)
Function: Controls the modulation input and depth, ASK / OOK control and clock output to external system (MCU)
Default: 0x91 at POR = H or EN = L, and at each write to ISO control register, except Clo1 and Clo0.
Bit
Name
Function
Description
B7
27MHz
Enables 27.12-MHz crystal
Default = 1 (enabled)
Enable ASK/OOK pin (pin 12) for "on the fly change" between any preselected
ASK modulation as defined by B0 to B2 and OOK modulation:
1 = Enables external
selection of ASK or OOK
modulation
0 = Default operation as
defined in B0 to B2 (0x09)
B6
B5
en_ook_p
If B6 is 1, pin 12 is configured as follows:
1 = OOK modulation
0 = Modulation as defined in B0 to B2 (0x09)
SYS_CLK Output SYS_CLK Output
Clo1
Clo0
(if 13.56-MHz
(if 27.12-MHz
crystal is used)
SYS_CLK output frequency
MSB
crystal is used)
Clo1
0
0
1
1
0
1
0
1
Disabled
3.39 MHz
6.78 MHz
13.56 MHz
Disabled
6.78 MHz
13.56 MHz
27.12 MHz
SYS_CLK output frequency
LSB
B4
B3
Clo0
1 = Sets pin 12 (ASK/OOK)
as an analog output
0 = Default
For test and measurement purpose. ASK/OOK pin 12 can be used to monitor
the analog subcarrier signal before the digitizing with DC level equal to AGND.
en_ana
Pm2
Pm1
Pm0
Mod Type and %
ASK 10%
B2
B1
B0
Pm2
Pm1
Pm0
Modulation depth MSB
Modulation depth
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
OOK (100%)
ASK 7%
ASK 8.5%
ASK 13%
ASK 16%
Modulation depth LSB
ASK 22%
ASK 30%
58
Register Description
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6.3.2.9 RX Special Setting Register (Address 0x0A)
Table 6-13. RX Special Setting Register (Address 0x0A)
Function: Sets the gains and filters directly
Default: 0x40 at POR = H or EN = L, and at each write to the ISO Control register 0x01. When bits B7, B6, B5 and B4 are all zero, the
filters are set for ISO14443B (240 kHz to 1.4 MHz).
Bit
B7
B6
Name
C212
C424
Function
Description
Bandpass 110 kHz to 570 kHz
Bandpass 200 kHz to 900 kHz
Appropriate for 212-kHz subcarrier system (FeliCa)
Appropriate for 424-kHz subcarrier used in ISO15693
Appropriate for Manchester-coded 848-kHz subcarrier used in ISO14443A
and B
B5
M848
Bandpass 450 kHz to 1.5 MHz
Bandpass 100 kHz to 1.5 MHz
Gain reduced for 18 dB
B4
B3
hbt
Appropriate for highest bit rate (848 kbps) used in high-bit-rate ISO14443
gd1
00 = Gain reduction 0 dB
01 = Gain reduction for 5 dB
10 = Gain reduction for 10 dB
11 = Gain reduction for 15 dB
Sets the RX gain reduction, and reduces sensitivity
B2
gd2
AGC activation level changed from five times the digitizing level to three
times the digitizing level.
1 = 3x
0 = 5x
B1
agcr
AGC activation level change
AGC action can be done any time during receive process. It is not limited
to the start of receive ("max hold").
1 = continuously – no time limit
B0
no-lim
AGC action is not limited in time
0 = 8 subcarrier pulses
The first four steps of the AGC control are comparator adjustment. The second three steps are real gain
reduction done automatically by AGC control. The AGC is turned on after TX.
The first gain and filtering stage following the RF envelope detector has a nominal gain of 15 and the 3-dB
band-pass frequencies are adjustable in the range from 100 kHz to 400 kHz for high pass and 600 kHz to
1.5 MHz for low pass. The next gain and filtering stage has a nominal gain of 8 and the frequency
characteristic identical to first stage. The filter setting is done automatically with internal preset for each
new selection of communication standard in ISO Control register (0x01). Additional corrections can be
done by directly writing into the RX Special Setting register 0x0A.
The second receiver gain stage and digitizer stage are included in the AGC loop. The AGC loop can be
activated by setting the bit B2 = 1 (agc-on) in Chip Status Control register 0x00. If activated the AGC
monitors the signal level at the input of digitizing stage. If the signal level is significantly higher than the
digitizing threshold level, the gain reduction is activated. The signal level, at which the action is started, is
by default five times the digitizing threshold level. It can be reduced to three times the digitizing level by
setting bit B1 = 1 (agcr) in RX Special Setting register (0x0A).
The AGC action is fast and it typically finishes after four subcarrier pulses. By default the AGC action is
blocked after first few pulses of subcarrier signal so AGC cannot interfere with signal reception during rest
of data packet. In certain cases, this is not optimal, so this blocking can be removed by setting B0 = 1
(no_lim) in RX Special Setting register (0x0A).
NOTE
The setting of bits B4, B5, B6 and B7 to zero selects bandpass characteristic of 240 kHz to
1.4 MHz. This is appropriate for ISO14443B, FeliCa protocol, and ISO14443A higher bit
rates 212 kbps and 424 kbps.
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6.3.2.10 Regulator and I/O Control Register (0x0B)
Table 6-14. Regulator and I/O Control Register (0x0B)
Function: Control the three voltage regulators
Default: 0x87 at POR = H or EN = L
Bit
Name
Function
Description
0 = Manual settings; see B0
to B2 in Table 6-15 and
Table 6-16
1 = Automatic setting; see
Table 6-17 and Table 6-18
Auto system sets VDD_RF = VIN – 250 mV and VDD_A = VIN – 250 mV and
VDD_X= VIN – 250 mV, but not higher than 3.4 V.
B7
auto_reg
Internal peak detectors are disabled, receiver inputs (RX_IN1 and RX_IN2)
accept externally demodulated subcarrier. At the same time ASK/OOK pin 12
becomes modulation output for external TX amplifier.
Support for external power
amplifier
B6
B5
en_ext_pa
io_low
When B5 = 1, maintains the output driving capabilities of the I/O pins connected
to the level shifter under low voltage operation. Should be set 1 when VDD_I/O
voltage is between 1.8 V to 2.7 V.
1 = enable low peripheral
communication voltage
B4
B3
B2
B1
B0
Unused
Unused
vrs2
No function
No function
Default is 0.
Default is 0.
Voltage set MSB voltage
set LSB
Vrs3_5 = L: VDD_RF, VDD_A, VDD_X range 2.7 V to 3.4 V; see Table 6-15 through
Table 6-18
vrs1
vrs0
Table 6-15. Supply-Regulator Setting – Manual 5-V System
Option Bits Setting in Control Register
Register
Action
B7
B6
B5
B4
B3
B2
B1
B0
00
0B
0B
0B
0B
0B
0B
0B
0B
0B
1
5-V system
0
0
0
0
0
0
0
0
0
Manual regulator setting
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
VDD_RF = 5 V, VDD_A = 3.5 V, VDD_X = 3.4 V
VDD_RF = 4.9 V, VDD_A = 3.5 V, VDD_X = 3.4 V
VDD_RF = 4.8 V, VDD_A = 3.5 V, VDD_X = 3.4 V
VDD_RF = 4.7 V, VDD_A = 3.5 V, VDD_X = 3.4 V
VDD_RF = 4.6 V, VDD_A = 3.5 V, VDD_X = 3.4 V
VDD_RF = 4.5 V, VDD_A = 3.5 V, VDD_X = 3.4 V
VDD_RF = 4.4 V, VDD_A = 3.5 V, VDD_X = 3.4 V
VDD_RF = 4.3 V, VDD_A = 3.5 V, VDD_X = 3.4 V
Table 6-16. Supply-Regulator Setting – Manual 3-V System
Option Bits Setting in Control Register
Register
Action
B7
B6
B5
B4
B3
B2
B1
B0
00
0B
0B
0B
0B
0B
0B
0B
0B
0B
0
3-V system
0
0
0
0
0
0
0
0
0
Manual regulator setting
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
VDD_RF = 3.4 V, VDD_A and VDD_X = 3.4 V
VDD_RF = 3.3 V, VDD_A and VDD_X = 3.3 V
VDD_RF = 3.2 V, VDD_A and VDD_X = 3.2 V
VDD_RF = 3.1 V, VDD_A and VDD_X = 3.1 V
VDD_RF = 3.0 V, VDD_A and VDD_X = 3.0 V
VDD_RF = 2.9 V, VDD_A and VDD_X = 2.9 V
VDD_RF = 2.8 V, VDD_A and VDD_X = 2.8 V
VDD_RF = 2.7 V, VDD_A and VDD_X = 2.7 V
60
Register Description
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Table 6-17. Supply-Regulator Setting – Automatic 5-V System
Option Bits Setting in Control Register
Action
B7
B6
B5
B4
B3
B2
B1
B0
1
00
0B
0B
0B
5-V system
(1)
1
1
1
x
1
1
0
1
Automatic regulator setting 250-mV difference
Automatic regulator setting 350-mV difference
Automatic regulator setting 400-mV difference
x
x
0
0
(1) x = don't care
Table 6-18. Supply-Regulator Setting – Automatic 3-V System
Option Bits Setting in Control Register
Register
B7
Action
B6
B5
B4
B3
B2
B1
B0
0
00
3-V system
(1)
0B
0B
0B
1
1
1
x
1
1
0
1
Automatic regulator setting 250-mV difference
Automatic regulator setting 350-mV difference
Automatic regulator setting 400-mV difference
x
x
0
0
(1) x = don't care
6.3.3 Status Registers
6.3.3.1 IRQ Status Register (0x0C)
Table 6-19. IRQ Status Register (0x0C)
Function: Information available about TRF7964A IRQ and TX/RX status
Default: 0x00 at POR = H or EN = L, and at each write to the ISO Control Register 0x01. It is also automatically reset at the end of a read
phase. The reset also removes the IRQ flag.
Bit
Name
Function
Description
Signals that TX is in progress. The flag is set at the start of TX but the interrupt
request (IRQ = 1) is sent when TX is finished.
B7
Irq_tx
IRQ set due to end of TX
Signals that RX SOF was received and RX is in progress. The flag is set at the
start of RX but the interrupt request (IRQ = 1) is sent when RX is finished.
B6
B5
B4
Irg_srx
Irq_fifo
Irq_err1
IRQ set due to RX start
Signals the FIFO is 1/3 >
FIFO > 2/3
Signals FIFO high or low
Indicates receive CRC error only if B7 (no RX CRC) of ISO Control register is
set to 0.
CRC error
B3
B2
Irq_err2
Irq_err3
Parity error
Indicates parity error for ISO14443A
Indicates framing error
Byte framing or EOF error
Collision error for ISO14443A and ISO15693 single subcarrier. Bit is set if more
then 6 or 7 (as defined in register 0x01) are detected inside one bit period of
ISO14443A 106 kbps. Collision error bit can also be triggered by external
noise.
B1
B0
Irq_col
Collision error
No response within the "No-response time" defined in RX No-response Wait
Time register (0x07). Signals the MCU that next slot command can be sent.
Only for ISO15693.
Irq_noresp
No-response timeinterrupt
To reset (clear) the register 0x0C and the IRQ line, the register must be read. During Transmit the
decoder is disabled, only bits B5 and B7 can be changed. During Receive only bit B6 can be changed, but
does not trigger the IRQ line immediately. The IRQ signal is set at the end of Transmit and Receive
phase.
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6.3.3.2 Collision Position Register (0x0D) and Interrupt Mask Register (0x0E)
Table 6-20. Collision Position Register (0x0D) and Interrupt Mask Register (0x0E)
Default: 0x3E at POR = H and EN = L. Collision bits reset automatically after read operation.
Bit
B7
B6
B5
B4
B3
Name
Col9
Function
Description
Bit position of collision MSB Supports ISO14443A
Bit position of collision
Col8
En_irq_fifo
En_irq_err1
En_irq_err2
Interrupt enable for FIFO
Interrupt enable for CRC
Interrupt enable for Parity
Default = 1
Default = 1
Default = 1
Interrupt enable for Framing
error or EOF
B2
B1
B0
En_irq_err3
En_irq_col
Default = 1
Default = 1
Default = 0
Interrupt enable for collision
error
Enables no-response
interrupt
En_irq_noresp
Table 6-21. Collision Position Register (0x0E)
Function: Displays the bit position of collision or error
Default: 0x00 at POR = H and EN = L. Automatically reset after read operation.
Bit
B7
B6
B5
B4
B3
B2
B1
B0
Name
Col7
Col6
Col5
Col4
Col3
Col2
Col1
Col0
Function
Description
Bit position of collision MSB
ISO14443A mainly supported, in the other protocols this register shows the bit
position of error. Either frame, SOF/EOF, parity or CRC error.
Bit position of collision LSB
62
Register Description
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6.3.3.3 RSSI Levels and Oscillator Status Register (0x0F)
Table 6-22. RSSI Levels and Oscillator Status Register (0x0F)
Function: Displays the signal strength on both reception channels and RF amplitude during RF-off state. The RSSI values are valid from
reception start till start of next transmission.
Bit
Name
Function
Description
B7
Unused
Crystal oscillator stable
indicator
B6
osc_ok
13.56-MHz frequency stable (≈200 µs)
MSB RSSI value of auxiliary
RX (RX_IN2)
B5
B4
B3
rssi_x2
rssi_x1
rssi_x0
Auxiliary channel is by default RX_IN2. The input can be swapped by B3 = 1
(Chip State Control register 0x00). If "swapped", the Auxiliary channel is
connected to RX_IN1 and, hence, the Auxiliary RSSI represents the signal level
at RX_IN2.
Auxiliary channel RSSI
MSB RSSI value of auxiliary
RX (RX_IN2)
MSB RSSI value of main
RX (RX_IN1)
B2
B1
B0
rssi_2
rssi_1
rssi_0
Active channel is default and can be set with option bit B3 = 0 of chip state
control register 0x00.
Main channel RSSI
LSB RSSI value of main RX
(RX_IN1)
RSSI measurement block is measuring the demodulated envelope signal (except in case of direct
command for RF amplitude measurement described later in direct commands section). The measuring
system is latching the peak value, so the RSSI level can be read after the end of receive packet. The
RSSI value is reset during next transmit action of the reader, so the new tag response level can be
measured. The RSSI levels calculated to the RF_IN1 and RF_IN2 are presented in Section 5.4.1.1 and
Section 5.4.1.2. The RSSI has 7 steps (3 bits) with 4-dB increment. The input level is the peak to peak
modulation level of RF signal measured on one side envelope (positive or negative).
6.3.3.4 Special Functions Register (0x10)
Table 6-23. Special Functions Register (0x10)
Function: User configurable options for ISO14443A specific operations
Bit
B7
B6
Name
Function
Description
Reserved
Reserved
Reserved
Reserved
Disables parity checking for
ISO14443A
B5
B4
B3
B2
par43
0 = 18.88 µs
1 = 37.77 µs
next_slot_37us
Sp_dir_mode
4_bit_RX
Sets the time grid for next slot command in ISO15693
Bit stream transmit for
MIFARE at 106 kbps
Enables direct mode for transmitting ISO14443A data, bypassing the FIFO and
feeding the data bit stream directly onto the encoder.
0 = normal receive
1 = 4-bit receive
Enable 4-bit replay for example, ACK, NACK used by some cards; for example,
MIFARE Ultralight
0 = anticollision framing
(0x93, 0x95, 0x97)
1 = normal framing (no
broken bytes)
Disable anticollision frames for 14443A (this bit should be set to 1 after
anticollision is finished)
B1
B0
14_anticoll
col_7_6
0 = 7 subcarrier pulses
1 = 6 subcarrier pulses
Selects the number of subcarrier pulses that trigger collision error in the
14443A - 106 kbps
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6.3.3.5 Special Functions Register (0x11)
Table 6-24. Special Functions Register (0x11)
Function: Indicate IRQ status for RX operations.
Bit
B7
B6
B5
B4
B3
B2
B1
Name
Function
Description
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Copy of the RX start signal
(Bit 6) of the IRQ Status
Register (0x0C)
Signals the RX SOF was received and the RX is in progress. IRQ when RX is
completed.
B0
irg_srx
6.3.3.6 Adjustable FIFO IRQ Levels Register (0x14)
Table 6-25. Adjustable FIFO IRQ Levels Register (0x14)
Function: Adjusts level at which FIFO indicates status by IRQ
Default: 0x00 at POR = H and EN = L
Bit
B7
B6
B5
B4
B3
Name
Function
Description
Reserved
Reserved
Reserved
Reserved
Wlh_1
Reserved
Reserved
Reserved
Reserved
Wlh_1
Wlh_0
IRQ Level
124
0
0
1
1
0
1
0
1
FIFO high IRQ level (during
RX)
120
112
96
B2
B1
B0
Wlh_0
Wll_1
Wll_0
Wll_1
Wll_0
IRQ Level
0
0
1
1
0
1
0
1
4
8
16
32
FIFO low IRQ level (during
TX)
64
Register Description
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6.3.4 Test Registers
6.3.4.1 Test Register (0x1A)
Table 6-26. Test Register (0x1A) (for Test or Direct Use)
Default: 0x00 at POR = H and EN = L.
Bit
B7
B6
Name
Function
Subcarrier Input
Description
OOK Pin becomes decoder digital input
OOK_Subc_In
MOD_Subc_Out Subcarrier Output
MOD Pin becomes receiver subcarrier output
Direct TX modulation and
RX reset
B5
B4
B3
MOD_Direct
o_sel
MOD pin becomes input for TX modulation control by the MCU
o_sel = L: Second Stage output used for analog out and digitizing
o_sel = H: Second Stage output used for analog out and digitizing
First stage output selection
Second stage gain -6 dB,
HP corner frequency/2
low2
First stage gain -6 dB, HP
corner frequency/2
B2
B1
B0
low1
zun
Input followers test
AGC test, AGC level is
seen on rssi_210 bits
Test_AGC
6.3.4.2 Test Register 0x1B
Table 6-27. Test Register (0x1B) (for Test or Direct Use)
Default: 0x00 at POR = H and EN = L. When a test_dec or test_io is set IC is switched to test mode. Test Mode persists until a stop
condition arrives. At stop condition the test_dec and test_io bits are cleared.
Bit
B7
B6
B5
B4
B3
B2
B1
B0
Name
Function
Description
test_rf_level
RF level test
test_io1
test_io0
test_dec
clock_su
I/O test
Not implemented
Decoder test mode
Coder clock 13.56 MHz
For faster test of coders
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6.3.5 FIFO Control Registers
6.3.5.1 FIFO Status Register (0x1C)
www.ti.com
Table 6-28. FIFO Status Register (0x1C)
Function: Number of bytes available to be read from FIFO (= N number of bytes, in hexadecimal)
Bit
B7
B6
B5
B4
B3
B2
B1
B0
Name
Foverflow
Fb6
Function
FIFO overflow error
FIFO bytes fb[6]
FIFO bytes fb[5]
FIFO bytes fb[4]
FIFO bytes fb[3]
FIFO bytes fb[2]
FIFO bytes fb[1]
FIFO bytes fb[0]
Description
Bit is set when FIFO has more than 128 bytes presented to it
Fb5
Fb4
Fb3
Fb2
Bits B0:B6 indicate how many bytes that are in the FIFO to be read out (= N
number of bytes, in hex)
Fb1
Fb0
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6.3.5.2 TX Length Byte1 Register (0x1D), TX Length Byte2 Register (0x1E)
Table 6-29. TX Length Byte1 Register (0x1D)
Function: High 2 nibbles of complete, intended bytes to be transferred through FIFO
Register default is set to 0x00 at POR and EN = 0. It is also automatically reset at TX EOF
Bit
Name
Function
Description
Number of complete byte
bn[11]
B7
Txl11
Number of complete byte
bn[10]
B6
B5
B4
B3
B2
B1
B0
Txl10
Txl9
Txl8
Txl7
Txl6
Txl5
Txl4
High nibble of complete, intended bytes to be transmitted
Number of complete byte
bn[9]
Number of complete byte
bn[8]
Number of complete byte
bn[7]
Number of complete byte
bn[6]
Middle nibble of complete, intended bytes to be transmitted
Number of complete byte
bn[5]
Number of complete byte
bn[4]
Table 6-30. TX Length Byte2 Register (0x1E)
Function: Low nibbles of complete bytes to be transferred through FIFO; Information about a broken byte and number of bits to be
transferred from it
Default: 0x00 at POR and EN = 0. It is also automatically reset at TX EOF
Bit
Name
Function
Description
Number of complete byte
bn[3]
B7
Txl3
Number of complete byte
bn[2]
B6
B5
B4
B3
B2
Txl2
Txl1
Txl0
Bb2
Bb1
Low nibble of complete, intended bytes to be transmitted
Number of complete byte
bn[1]
Number of complete byte
bn[0]
Broken byte number of bits
bb[2]
Broken byte number of bits Number of bits in the last broken byte to be transmitted.
bb[1]
It is taken into account only when broken byte flag is set.
Broken byte number of bits
bb[0]
B1
B0
Bb0
Bbf
Broken byte flag
B0 = 1, indicates that last byte is not complete 8 bits wide.
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7 System Design
7.1 Layout Considerations
Keep all decoupling capacitors as close to the IC as possible, with the high-frequency decoupling
capacitors (10 nF) closer than the low-frequency decoupling capacitors (2.2 µF).
Place ground vias as close as possible to the ground side of the capacitors and reader IC pins to minimize
possible ground loops.
It is not recommend to use any inductor sizes below 0603, as the output power can be compromised. If
smaller inductors are necessary, output performance must be confirmed in the final application.
Pay close attention to the required load capacitance of the crystal, and adjust the two external shunt
capacitors accordingly. Follow the recommendations of the crystal manufacturer for those values.
There should be a common ground plane for the digital and analog sections. The multiple ground sections
or islands should have vias that tie the different sections of the planes together.
Ensure that the exposed thermal pad at the center of the reader IC is properly laid out. It should be tied to
ground to help dissipate any heat from the package.
All trace line lengths should be made as short as possible, particularly the RF output path, crystal
connections, and control lines from the reader to the microprocessor. Proper placement of the TRF7964A,
microprocessor, crystal, and RF connection/connector help facilitate this.
Avoid crossing of digital lines under RF signal lines. Also, avoid crossing of digital lines with other digital
lines when possible. If the crossings are unavoidable, 90° crossings should be used to minimize coupling
of the lines.
Depending on the production test plan, consider possible implementations of test pads or test vias for use
during testing. The necessary pads or vias should be placed in accordance with the proposed test plan to
enable easy access to those test points.
If the system implementation is complex (for example, if the RFID reader module is a subsystem of a
greater system with other modules (Bluetooth, WiFi, microprocessors, and clocks), special considerations
should be taken to ensure that there is no noise coupling into the supply lines. If needed, special filtering
or regulator considerations should be used to minimize or eliminate noise in these systems.
For more information/details on layout considerations, see the TRF796x HF-RFID Reader Layout Design
Guide (SLOA139).
7.2 Impedance Matching TX_Out (Pin 5) to 50 Ω
The output impedance of the TRF7964A when operated at full power out setting is nominally 4 + j0 (4 Ω
real). This impedance must be matched to a resonant circuit and TI recommends matching circuit from
4 Ω to 50 Ω, as commercially available test equipment (for example, spectrum analyzers, power meters,
and network analyzers) are 50-Ω systems. An impedance-matching reference circuit can be seen in
Figure 7-1 and Figure 7-2. This section explains how the values were calculated.
Starting with the 4-Ω source, the process of going from 4 Ω to 50 Ω can be represented on a Smith Chart
simulator (available from http://www.fritz.dellsperger.net/). The elements are combined where appropriate
(see Figure 7-1).
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Figure 7-1. Impedance Matching Circuit
This yields the Smith Chart Simulation shown in Figure 7-2.
Figure 7-2. Smith Chart Simulation
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Resulting power out can be measured with a power meter or spectrum analyzer with power meter function
or other equipment capable of making a "hot" measurement. Observe maximum power input levels on test
equipment and use attenuators whenever available to avoid damage to equipment. Expected output
power levels under various operating conditions are shown in Table 6-2.
7.3 Reader Antenna Design Guidelines
For HF antenna design considerations using the TRF7964A, see these documents:
•
•
Antenna Matching for the TRF7960 RFID Reader (SLOA135)
TRF7960TB HF RFID Reader Module User's Guide (SLOU297)
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SLOS787A –MAY 2012–REVISED JUNE 2012
8 Revision History
Revision
Comments
SLOS787
Initial release
SLOS787A
Section 3.3, Corrected Power Rating for TA ≤ 25°C.
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PACKAGE OPTION ADDENDUM
www.ti.com
24-Jul-2012
PACKAGING INFORMATION
Status (1)
Eco Plan (2)
MSL Peak Temp (3)
Samples
Orderable Device
Package Type Package
Drawing
Pins
Package Qty
Lead/
Ball Finish
(Requires Login)
TRF7964ARHBR
TRF7964ARHBT
ACTIVE
ACTIVE
QFN
QFN
RHB
RHB
32
32
3000
250
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-2-260C-1 YEAR
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-2-260C-1 YEAR
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 1
IMPORTANT NOTICE
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