TMS37157
www.ti.com
SWRS083A – SEPTEMBER 2009 – REVISED NOVEMBER 2009
PASSIVE LOW FREQUENCY INTERFACE DEVICE WITH EEPROM
AND 134.2 kHz TRANSPONDER INTERFACE
Check for Samples: TMS37157
FEATURES
APPLICATIONS
•
•
•
1
•
•
•
•
Wide Supply Voltage Range 2 V to 3.6 V
Ultra Low Power Consumption
– Active Mode Max. 150 μA
– Power Down Mode 60 nA
121 Free Bytes User Memory
Low Frequency Halb Duplex (HDX) Interface
– HDX Transponder Communication
Achieving Maximum Perfomance and
Highest Noise Immunity
– Special Selective Addressing Mode Allows
Anti Collision
– Up to 8 kbit/s LF Uplink Data Rate
– 126 Byte EEPROM:
– 121 Bytes Free Available EEPROM User
Memory
– 32 Bit Unique Serial Number
– 8 Bit Selective Address
– High EEPROM Flexibility
– Pages are Irreversible Lockable and
Protectable
– Battery Check and Battery Charge Function
– Resonance Frequency: 134.2 kHz
– Integrated Resonance Frequency Trimming
– Downlink – Amplitude Shift Keying
– Uplink – Frequency Shift Keying
3 Wire SPI Interface for Accessing the
EEPROM and Exchanging Data With the
Microcontroller Through the LF Interface
0.6mm Pitch, 4mm x 4mm VQFN Package
•
•
•
•
•
Wireless Batteryless Sensor Interface using
Energy Harvesting
– Microcontroller and Sensor can be
Powered Through the LF Link
– Data is Directly Transmitted Over the LF
Link From the Base Station via the
TMS37157 to the Micrcontroller and Vice
Versa.
Batteryless Configuration Memory
– Memory can be Written Without Battery
Support
– Microcontroller can Read the Content of the
Memory When It Gets Connected to a
Battery and Use It for Configuration
– Microcontroller can Write the Memory,
Which can be Read Out Later Through the
LF Link
Ultra Low Power Data Logger Memory (Smart
Metering)
– Memory Can Be Written By a
Microcontroller
– Memory Can Be Read Through LF Interface
Without Battery Support
Multi Purpose LF Interface to a Microcontroller
– Short Range RF Interface to a
Microcontroller Where Other Frequencies
are Not an Option
– Ultra Low Power Mode can Result in an
Overall Power Consumption of 60 nA
Remote Control Application
– Combination With an UHF Transmitter or IR
Transmitter and a μC
– Power Management of the TMS37157 can
Power Down the Microcontroller
– The Push Button Detection Circuit can
Power Up a Microcontroller
Stand Alone LF-Transponder with Memory
– RFID Transponder with Unique ID and 121
Bytes Free Programmable EEPROM User
Memory
– Only Few Additional Components Needed
– No Battery Required
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 © 2009, Texas Instruments Incorporated
TMS37157
SWRS083A – SEPTEMBER 2009 – REVISED NOVEMBER 2009
www.ti.com
DESCRIPTION/ORDERING INFORMATION
The TMS37157 combines a Low Frequency Transponder Interface with an SPI Interface and Power
Management for a connected microcontroller. It is the ideal device for any Configuration, Data Logger-, Sensoror Remote Control Application. The Transponder memory is accessible through SPI and LF and, in the second
case, operates without the need for a battery. The use of the Low Frequency Band ensures a communication in
a defined direction and harsh environments.
The TMS37157 manages the Transponder communication and push button interaction. During sleep state the
devices enters a special low power mode with only 60 nA current consumption.
The EEPROM memory is accessible over the LF interface without support from the battery or through SPI by a
microcontroller if a battery is connected. The TMS37157 offers a special battery charge mode.
The external resonance circuit with a LF coil and a resonance capacitor can be trimmed to the correct resonance
frequency with the integrated trimming capability achieving an easy way to eliminate part tolerances.
The small RSA 16-pin package together with only a few external components results in a cost efficient design.
Digital or Analog
Sensor
Microcontroller
ENERGY
LF Reader
134,2 kHz
LF DATA
Base Station
2
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TMS37157
Sensor System
Copyright © 2009, Texas Instruments Incorporated
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TMS37157
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SWRS083A – SEPTEMBER 2009 – REVISED NOVEMBER 2009
VBAT
VBATI
GND
VCL
PIN CONFIGURATION
16 15 14 13
11 SPI_SOMI
TDAT 3
10 SPI_CLK
TEN 4
9 CLK_AM
6
7
8
BUSY
5
PUSH
TCLK 2
NPOR
12 SPI_SIMO
EOB
RF1 1
TERMINAL FUNCTIONS
TERMINAL
NAME
NO.
I/O
DESCRIPTION
RF1
1
I
Antenna
TCLK
2
I
Test interface - clock input. Data is shifted in and out of the TDAT pin on the rising edge of
TCLK.
TDAT
3
I/O
TEN
4
I
Test interface – enable input.
EOB
5
O
End of burst detector. This signal is high when the RF signal of the base station is OFF.
NPOR
6
O
Active low power-on-reset (open drain) - can be used to reset the microcontroller.
PUSH
7
I
Input of the push button detector – can be used to recognize that a push event has occurred.
Test interface – bidirectional serial data I/O for configuration and trimming.
BUSY
8
O
Indicates internal control unit activity:
•
During initialization
•
During transponder operation
•
During SPI communication (handshaking)
CLKA_M
9
O
This output provides clock signals derived from the external antenna resonance circuit to the
microcontroller. This function can be activated by an SPI command. Two frequencies are
selectable FRES and FRES/4.
SPI_CLK
10
I
SPI clock input
SPI_SOMI
11
O
SPI data output
SPI_SIMO
12
I
SPI data input
VBATI
13
PWR
Can be used as μC supply voltage
VBAT
14
PWR
Battery supply
GND
15
PWR
Ground
VCL
16
PWR
Charge capacitor
ORDERING INFORMATION
TA
–40°C to 85°C VQFN – RSA
(1)
(2)
PACKAGE
(1) (2)
ORDERABLE PART NUMBER
Reel of 3000
TMS37157IRSARG4
TOPSIDE MARKING
37157I
Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
website at www.ti.com.
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TMS37157
SWRS083A – SEPTEMBER 2009 – REVISED NOVEMBER 2009
www.ti.com
ABSOLUTE MAXIMUM RATINGS (1)
over operating free-air temperature range (unless otherwise noted)
TA
Operating free air temperature
Ts
Storage temperature
VBAT
Battery voltage
VCL
VCL input voltage
IRF
Input current (3)
(1)
(2)
(3)
(2)
MIN
MAX
–40
85
UNIT
°C
–40
125
°C
–0.3
3.6
V
7
V
10
mA
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 "recommended operating
conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
One cycle up to 1000h
Continuous
OPERATING CONDITIONS
PARAMETER
Qop
Operating system quality factor
VBAT
Battery voltage
MIN
TYP
MAX
UNIT
≥30
2
3
3.55
V
MIN
TYP
MAX
UNIT
IC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE
SUPPLY AND REFERENCE CURRENTS
PARAMETER
IVBATI
Current out of VBATI
VBAT = 2.0 V
dVsw2
Voltage drop at SW2 (VBAT – VBATI)
IBATI = 16 mA, VBAT = 2.0 V
Iquiet
Quiescent current
TMS37157 idle
Iactive
Operating current
TMS37157 active
Icharge
Battery charge current
60
16
mA
100
mV
300
nA
150
μA
2
mA
MODULATION CAPACITOR
PARAMETER
CM
Modulation capacitor
MIN
L = 2.66 mH
NOM
MAX
110
UNIT
pF
FRONT END CONTROL
PARAMETER
treset
TMS37157 front-end reset time
tHdet
High bit detection threshold time
MIN
NOM
MAX
14
fTX = 134.2kHz
64/fTX
UNIT
ms
us
CHARACTERISTICS OF TRANSPONDER SECTION
PARAMETER
MIN
tprebit
Prebit time
fL = 134.7kHz
ttrans
High bit transition time of start byte 0x7E
thigh
High bit time
tlow
Low bit time
Tresp
Response time
NOM
MAX
UNIT
1.9
ms
2
ms
fH = 123.7kHz
0.129
ms
fL = 134.7kHz
0.118
ms
12
ms
VCL/VBAT CHECKER
PARAMETER
MIN
NOM
MAX
UNIT
High Level VBAT checker threshold voltage
2.9
V
Low Level
2.1
V
4
VBAT checker threshold voltage
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VCL/VBAT CHECKER (continued)
PARAMETER
MIN
NOM
MAX
UNIT
Vcharge
VBAT charge voltage
3.4
V
Vch
VCL checker threshold voltage
3.1
V
TRIMMING CAPACITORS AND SWITCHES
PARAMETER
Tstep
Trimming steps
CTmin
Minimum trimming capacitor
CT1
CT2
MIN
NOM
MAX
UNIT
128
0
pF
Trimming capacitor 1
0.6
pF
Trimming capacitor 2
1.2
pF
CT3
Trimming capacitor 3
2.4
pF
CT4
Trimming capacitor 4
4.7
pF
CT5
Trimming capacitor 5
9.4
pF
CT6
Trimming capacitor 6
18.8
pF
CT7
Trimming capacitor 7
CT
Maximum trimming capacitor (CT = CT1+ CT2+ … + CT7)
37.6
pF
63.5
74.4
85.9
pF
MIN
NOM
MAX
UNIT
RF LIMITER
PARAMETER
VRFlim
RF limiter voltage
VCLlim
Limited VCL voltage
Limited VCL voltage is the result of the RF
limiter in the application circuit
10.5
12
14
V
5.75
5.9
6.5
V
NOM
MAX
CONTROL AND SPI INTERFACE
PARAMETER
MIN
UNIT
Busy low time
See SPI Comm.
30-70
μs
Busy high time
See SPI Comm.
10-30
ms
PARAMETER
MIN
VOL
Low level output voltage, SPI_SOMI, VBAT = 2.0…3.6V, RL = 100 kΩ
BUSY
VOH
High level output voltage,
SPI_SOMI, BUSY
VBAT = 2.0…3.6V, RL = 100 kΩ
VIL
Low level input voltage, SPI_SIMO,
SPI_CLK
VBAT = 2.0…3.6V, RL = 100 kΩ
VIH
High level input voltage, SPI_SIMO,
SPI_CLK
VBAT = 2.0…3.6V, RL = 100 kΩ
0.93 ×
VBAT
NOM
MAX
0.05 ×
VBAT
0.07 ×
VBAT
UNIT
V
0.95 ×
VBAT
0.9 ×
VBAT
V
0.1 ×
VBAT
V
VBAT
V
UNIT
ACTIVATION LIMIT OF TMS37157
PARAMETER
Vact
(1)
Activation level for transponder
response
f = 134.2 kHz (1)
MIN
NOM
MAX
5.75
5.9
6.5
V
At beginning of the response the voltage VCL must be just limited. Only in this case the function is guaranteed if components and IC
parameters are at the limit, see Figure 1 . The voltage is measured at VCL just before the Transponder starts with the response protocol.
The longest in the application used downlink telegram with maximum number of high bits should be used. The low and high bit response
frequency should be at the lowest value which occurs in the application. In case of an additional power phase (Programming) the level
has to be after that additional power phase.
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TMS37157
SWRS083A – SEPTEMBER 2009 – REVISED NOVEMBER 2009
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Transponder Charge
Tx
Vcl
5.75
0V
Figure 1. Activation limit of TMS37157
MEMORY
PARAMETER
MIN
P/E-C
Program/erase cycles
25°C
XDRET
Data retention
Ts = 25°C
TYP
MAX
UNIT
200000
Cycles
10
Years
TEST INTERFACE
PARAMETER
MIN
TYP
MAX
UNIT
RTCLK
Pull-down resistor, TCLK
7
10
25
kΩ
RTDAT
Pull-down resistor, TDAT
20
150
375
kΩ
RTEN
Pull-down resistor, TEN
5
10
25
kΩ
VOL
Low level output voltage, TDAT
VCL = 5V, RL = 2.5 kΩ
VOH
High level output voltage, TDAT
VCL = 5V, RL = 2.5 kΩ
0.25
4.75
V
V
TRANSPONDER MODE
TRANSPONDER TIMING USING PPM
PARAMETER
MIN
TYP
MAX
UNIT
PPM - Pulse Position Modulation
tofftrp
Write pulse pause (PPM) (1)
170
μs
tontrpL
Write pulse activation/ low bit (PPM) (1)
230
μs
350
μs
tontrpH
Write pulse activation/ high bit (PPM)
tbittrpL
Write low bit period (1)
tbittrpH
Write high bit period (1)
(1)
(2)
(3)
(1)
μs
400
(2) (3)
510
520
1730
μs
This timing is measured at the transponder using a pickup coil. This timing is with Low Bit Frequency = 134.7kHz and is influenced by
various factors e.g. detuning and coupling to the reader antenna and. Out of this timing the low and high bit are detected by the
transponder logic.
Except the last bit this limitation of the duration is valid for all downlink bits.
To detect a High bit the absolute minimum of tbittrpH = 510 μs must be met.
READER RECOMMENDATIONS
PARAMETER
QTX,
QRX
Reader operating quality factor
fTX
Transmitter frequency
tTX
Charge time
tTXoff
Transmitter off time
tprog
Programming time
tRD
Read time
6
MIN
TYP
MAX
UNIT
10
134.16
134.2
20
25
3
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kHz
ms
ms
15
14.9
134.24
ms
15
ms
Copyright © 2009, Texas Instruments Incorporated
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TMS37157
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SWRS083A – SEPTEMBER 2009 – REVISED NOVEMBER 2009
READER TIMINGS USING PPM
PARAMETER
MIN
TYP
MAX
UNIT
PPM - Pulse Position Modulation
toff
Off time (PPM) (1)
170
μs
tonL
Low bit on time (PPM) (1)
230
μs
400
μs
(1)
tbitL
Low bit duration (PPM)
tonH
High bit on time
tbitH
High bit duration (PPM) (1)
(1)
(1)
μs
350
520
1730
μs
TYP
MAX
UNIT
Timing recommendation is only valid for a Reader Operating Quality Factor QTX = QRX ≤ 10.
ANTENNA CURRENTS FOR EQUIVALENT FIELD STRENGTH LEVELS
PARAMETER
Ishort
(1)
(1)
MIN
Equivalent current for operation (True RMS)
Iprog
4.3
mA
The circuit below is used to determine equivalent short circuit current at the position of the TMS37157 transponder coil.
The measured value must be equal or above the specified value in the table above. The operating Q factor Qop depends on used
components (L, C) and the application environment.
PARAMETER
Ishort
Ishort
Tcharge = 20 ms
Tcharge = 25 ms
UNIT
Iprog
Equivalent for programming activation
field strength
Qop ≥ 60
–40 to 85 °C
0.32
0.23
mA
Iprog
Equivalent for programming activation
field strength
Qop ≥ 30
–40 to 85 °C
0.64
0.46
mA
I sho rt
I
Figure 2. Short Circuit Current
RECOMMENDED EXTERNAL COMPONENTS
ANTENNA
PARAMETER
LR
dLR/LRdT
QLR
(1)
(2)
(1)
TEST CONDITIONS
Inductance of antenna
(dLR = ± 2.8%)
25°C CR = 470 pF, ±2% f= 134.2
kHz
Temperature coefficient of LR
–40 to 85°C
Quality factor of LR
25°C* Qop > 30
MIN
NOM
MAX
UNIT
2.586
2.66
2.734
mH
(2) (1)
250
ppm/K
60
Qop is Q factor measured when device is assembled on PCB.
Due to tester limitations currently only the value given in brackets can be guaranteed.
RESONANCE CIRCUIT CAPACITOR
PARAMETER
CR
LR = 2.66 mH ± 2.8%
Dielectric
dLR/LRdt ≤ 250 ppm (1)
QCR
Quality factor
RF
Operating voltage
(1)
TEST CONDITIONS
Resonance capacitor
MIN
NOM
MAX
UNIT
460.6
470
479.4
pF
NP0
2000
20
50
Vpp
This type is recommended, if no temperature compensation is required for LR
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TMS37157
SWRS083A – SEPTEMBER 2009 – REVISED NOVEMBER 2009
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CHARGE CAPACITOR
PARAMETER
CL
Charge capacitor
CLdiel
Dielectric of CL
VCL
Operating voltage
TEST CONDITIONS
MIN
TYP
MAX
UNIT
25°C
fmeas = 1 kHz
198
220
242
nF
X7R
16
Vdc
OTHER COMPONENTS
PARAMETER
TEST CONDITIONS
MIN
NOM
MAX
UNIT
RVCL
VCL resistor
Depends on application circuit
1
MΩ
Rload
VBATI load resistor
Depends on application circuit
100
kΩ
CBAT
Battery capacitor
100
nF
CBATI
BATI capacitor
100
nF
RECOMMENDED TEST INTERFACE PARAMETERS
PARAMETER
MIN
NOM
MAX
VCL
Supply voltage for trim/test
VIH
High level input voltage, TDAT, TCLK & TEN
0.9 × VCL
5
1.1 × VCL
VIL
Low level input voltage, TDAT, TCLK & TEN
0
0.1 × VCL
fTclk
Clock frequency
tr, tf
tTclkl
TCLK
UNIT
V
V
V
134
kHz
Rise and fall time, TDAT, TCLK, TEN
50
ns
Test clock low time
3.7
μs
tTclkh
Test clock high time
3.7
μs
tTres
Test reset time
14
ms
tTrc
Test reset to clock time
1
μs
tTds
Test data setup time
1
μs
tTdh
Test data hold time
1
μs
ANALOG
FRONT END
BUSY
CONTROL
UNIT
VCL
CLKA/M
TEN
EOB
TCLK
RF1
TDAT
TMS37157 BLOCK DIAGRAM
SPI_SIMO
SPI_SOMI
SPI_CLK
VBAT
POWER
MANAGEMENT
TANSPONDER & USER
MEMORY
GND
VBATI
NPOR
PUSH
8
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SWRS083A – SEPTEMBER 2009 – REVISED NOVEMBER 2009
BLOCK DESCRIPTION
Analog Front End
The Analog Front End implements all of the analog functions needed to support the TMS37157 transponder
functions. It enables reception and transmission of LF signals when the transponder is active, and rectifies
incoming LF energy and stores it in an external charge capacitor, to power the device.
The Analog Front End also contains the capacitor array used to trim the transponder's resonance circuit and a
clock regenerator function, which is able to recover the clock from an incoming signal so it can be used by the
transponder functions.
Control Unit
DST Transponder
The transponder implemented in the TMS37157 is compatible with Texas Instruments' DST ("Digital Signature
Transponder") transponder. In addition the TMS37157 provides additional Memory for customer use.
CRC Calculation
A hardware cyclic redudancy check calculation engine is implemented in the Control Unit to provide error
detection.
Memory Access
The Control Unit interfaces to the on-chip EEPROM. During power-up, the Control Unit reads the configuration
parameters stored in the EEPROM and initializes the TMS37157 circuitry accordingly, and at various times
during device operation it can read EEPROM data and provide it, for example, to a microcontroller.
SPI Interface
The Control Unit provides an SPI interface that allows it to communicate with a microcontroller. Via this interface,
for example, the microcontroller is able to access the contents of the TMS37157 EEPROM.
Test Interface
The Control Unit provides a test interface that allows customers to trim the LF antenna's resonance circuit.
Transponder and User Memory
The Transponder Memory comprises a total of 126 bytes, organized in pages. Memory space is apportioned as
follows:
• User Data 121 bytes
• Serial Number + Manufactorer Code 4 bytes
• Selective Address 1 byte
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TMS37157
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MSB
10
LOCK
PAGE 1
DATA
PAGE 2
USER DATA
USER DATA
USER DATA
USER DATA
PAGE 9
DATA
PAGE 10
DATA
PAGE 11
DATA
PAGE 12
LOCK
DATA
DATA
PAGE 13
LOCK
PAGE 8
DATA
PAGE 14
LOCK
LOCK
USER DATA
DATA
LOCK
USER DATA
PAGE 3
LOCK
USER DATA
MANUF.
CODE
LOCK
USER DATA
SERIAL
NUMBER
LOCK
UNIQUE IDENTIFICATION
LOCK
USER DATA
e.g
.
PASSWORD
LOCK
SELECT. ADDRESS
LSB
DATA
PAGE 15
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SWRS083A – SEPTEMBER 2009 – REVISED NOVEMBER 2009
LOCK
PAGE 40
LOCK
DATA
PAGE 41
DATA
PAGE 42
DATA
PAGE 43
DATA
PAGE 44
DATA
PAGE 45
DATA
PAGE 46
DATA
PAGE 47
DATA
PAGE 48
USER DATA
USER DATA
USER DATA
USER DATA
USER DATA
USER DATA
USER DATA
USER DATA
USER DATA
USER DATA
USER DATA
USER DATA
USER DATA
LOCK
USER DATA
DATA
PAGE 49
LOCK
USER DATA
DATA
PAGE 50
LOCK
USER DATA
LOCK
DATA
LOCK
40 LSB
LOCK
32
LOCK
24
LOCK
16
LOCK
8
LOCK
MSB
LOCK
1
DATA
PAGE 51
LOCK
DATA
PAGE 53
LOCK
PAGE 52
DATA
PAGE 54
LOCK
DATA
DATA
PAGE 55
Selective Address
Page 1 of the transponder memory contains a Selective Address (password) and lock bit. The Selective Address
is used for selective programming, selective locking,selective protecting and selective reading.
The Selective Address may be programmed by the user via the program page 1 command (as long as the
Selective Address lock bit is not set). The lock bit can be set by the user via the lock page 1 command. Once
set, the lock bit cannot be reset.
To activate the selective addressing feature, the user must write a value other than 0xFF into page 1. If the
Selective Address is not 0xFF, it is compared with the Selective Address received from the base station during a
command write phase. If the Selective Address is 0xFF (the factory default), no such comparison is performed
and selective addressing is disabled.
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Whenever pages 1, 2 or 3 are accessed, the Selective Address (from page 1) is returned in the corresponding
read phase, together with page 2 and the Manufacturer Code and Serial Number (from page 3). The status of the
page 1 lock bit (1=locked) is only returned when page 1 is accessed.
Page 2
Page 2 of the transponder memory contains 8 bits of user data and lock bit.
Page 2 is typically used for numbering keys in an application (e.g. the key number), it can also be used so save
the value of the trim capacitor array or for anything else. It may be programmed by the user using the program
page 2 command (as long as the lock bit is not set). The lock bit can be set by the user via the lock page 2
command. Once set, the lock bit cannot be reset.
Whenever pages 1, 2 or 3 are accessed, page 2 is returned in the corresponding read phase, together with the
Selective Address (from page 1) and the Manufacturer Code and Serial Number (from page 3). The status of the
page 2 lock bit (1=locked) is only returned when page 2 is accessed.
Unique Identification
Page 3 of the transponder memory contains an 8-bit Manufacturer Code and a 24-bit Serial Number. The
Manufacturer Code and Serial Number are programmed and locked during manufacture and cannot be changed.
The Manufacturer Code is used to distinguish between different devices, the Manufacturer Code of the
TMS37157 is 0x0E. The Serial Number is unique for every single TMS37157 device.
Whenever pages 1, 2 or 3 are accessed, the Manufacturer Code and Serial Number (from page 3) are returned
in the corresponding read phase, together with the Selective Address (from page 1) and page 2. The status of
the page 3 lock bit (1=locked) is only returned when page 3 is accessed.
User Data
The Transponder Memory provides the Pages 2, 8 to 15 and 40 to 55 for data storage. This memory is available
to store any data defined by the user or application.
12
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POWER MANAGEMENT
The Power Management block is responsible for the master control of all power supplies plus several additional
tasks, such as responding when a push button is pressed, generating reset signals and receiving LF transponder
commands.
A block diagram of the power management function is shown in Figure 3. Activation of a push signal is detected
by an ultra low-power detection circuit. While waiting for a high signal at PUSH, the only active component in
theTMS73157 is a flip-flop, whose output is set when PUSH is set high. When this happens, SW5 is closed and
the Control Unit is powered up and initialized. Also VBAT is switched to VBATI to power up a connected
microcontroller. The Microcontroller can, after performing its desired actions, send a Power Down Command to
the TMS37157, bringing the TMS37157 in the ultra low power mode (the Flip Flip is cleared and VBATI is
disconnected waiting for a PUSH High signal to appear.
When the Transponder Interface receives an MSP Access Command the Control Unit is powered up and
initialized and sets the VBATI ON signal, which switches on the uC. The Control Unit waits for μC to fetch the
data, process it and send the processed data back to the Control Unit. The TMS37157 switches VBATI off and
waits for the RF to switch. If it detects a loss of the RF is transmitts the MSP Access data back .Then the
TMS37157 goes into the ultra low power sleep mode again. Throughout the whole MSP Access process the RF
of the reader has to stay on, because the TMS37157 Control Unit is powered out of the RF - field.
TMS37157
EEPROM
ROM
CRC
GEN.
RF
TRP
INTF.
LR
CLKA/M
CR
CHARGE
REG.
CL
RVCL
VOLT.
REG.
VCL
SIMO
VBATI
CONTROL
UNIT
S
P
I
VCCD
SOMI
SPI_CLK
BUSY
GND
SW5
CLEAR
VBATION
Q CL
S
VBAT
BATBATI
VBAT
BAT
VBATI
PUSH
+
CBAT
CBATI
RVBATI
I
Figure 3. TMS37157 Power Management
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ADRESSING OF THE TRANSPONDER
The addressing mode of the TMS37157 is defined by the content of page 1.
General Addressing Page 1 = 0xFF
Selective Addressing Page 1 0xFF
Standard configuration is General Addressing. Selective Addressing is activated by programming a value other
than 0xFF into page 1 of the TMS37157 EEPROM. Selective Addressing affects the Lock Page, Protect Page
(not available for Page 1-3) and Program Page commands for page 1 to page 15 and page 40 to page 55. Here
the selective address has to be added to the Command. A Read Page of page 1 – 3 always gives back the
selective address.
A General Read is still possible on all pages. For page 1 – 3 a selective read be can done.
To switch off Selective Addressing a selective program page 1 Command with User Data 0xFF has to be send to
the TMS37157.
USE OF THE LOCK BIT
All pages can be locked by setting the corresponding lock bit. Locked pages can not be reprogrammed anymore.
The Lock is irreversible.
USE OF THE PROTECTION BIT
Pages 8-15 and 40-55 can be protected by setting the corresponding Protection Bit. Protected pages can only be
repgrammed via SPI. The TMS37157 will not answer to a program command on a protected page. General and
Selective Read commands are still possible on protected pages. The protection is irreversible.
14
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PULSE POSITION MODULATION
With Pulse Position Modulation the information is carried in the period duration of a bit (tbitL, tbitH). A bit consists of
a pulse pause (toff) and a pulse activation (tonL, tonH).
The difference of period durations at the reader must be selected in way that in case of a low bit the duration at
the transponder location is lower than the High Bit Threshold Detection Time (tHdet). For a high bit, the bit
duration mus at the transponder location must be higher that the High Bit Threshold Detection Time (tHdet).
PPM in Case of General Read
Figure 4. PPM in Case of General Read
If the Pause between to positive transitions of EOB is at least as long as tHdet the Transponder writes a one. Is
the Pause shorter it writes a 0.
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PPM in Case of Programming or Locking
Figure 5. PPM in Case of Programming
For a program, lock or protect command a RF burst from the transmitter is needed after transmitting the
program, lock or protect command, the length has to be at least tprg.
16
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TMS37157 COMMANDS
This chapter describes the commands and data that can be transferred to and from the TMS37157 via its contact
less LF interface, SPI and Test interfaces.
When communicating with the transponder following naming conventions are used:
• Data Transmission from the base station to the transponder is called “write” and “write data are transferred”.
• Data Transmission from the transponder to the base station is called “read” and “read data re transferred”.
This is applied independently from the command that is executes whether it is a read, write, program or
authentication function.
Write Formats
In order to send commands to the TMS37157 LF interface, the user sends a Write Address byte comprising a
2-bit Command field and a 6-bit Page field. The Command field, which is transmitted first, determines the
function to be executed and whether command comprises additional data bytes that must also be sent. The Page
field specifies the target of the command.
Table 1 shows which additional data bytes must be included with each command type. The elements for each
command are sent from left to the right of this table.
Table 1. Data Bytes for different command types
WRITE ADDRESS
FUNCTION
COMMAND FIELD
PAGE FIELD
SELECTIVE
ADDRESS
WRITE DATA
FRAME BCC
MSB LSB
General read page, battery
check
00
X
Selective read page
11
X
Program page; MSP access
01
X
Selective program page
01
X
Lock page
10
X
Selective lock page
10
X
Protect page
11
X
Selective protect page
11
X
(1)
X
X
X
X (1)
X
X (1)
X
X
X
X
X
X
X
Length of Wrtite Data is 5 bytes for a program page command and 6 bytes for an MSP Access command.
The summary for the available write address via the LF interface are shown in Table 2. It shows the valid
Command and Page field combinations supported by the TMS37157.
Table 2. Valid Command and Page Field Combinations (Command)
WRITE ADDRESS
Page 1
Page 2
MSB
PPPPPP
|
PAGE FIELD
MSB LSB
LSB
CC
|
COMMAND
FIELD
MSB LSB
000001
00
04h
General Read Page 1
000001
01
05h
Program/Selective Program Page 1
000001
10
06h
Lock/Selective Lock Page 1
000001
11
07h
Selective Read Page 1
000010
00
08h
General Read Page 2
000010
01
09h
Program/Selective Program Page 2
000010
10
0Ah
Lock/Selective Lock Page 2
000010
11
0Bh
Selective Read Page 2
HEX
VALUE
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Table 2. Valid Command and Page Field Combinations (Command) (continued)
WRITE ADDRESS
Page 3
000011
00
0Ch
General Read Page 3
000011
01
0Dh
Program/Selective Program Page 3
000011
10
0Eh
Lock/Selective Lock Page 3
000011
11
0Fh
Selective Read Page 3
001000
00
20h
General Read Page 8
001000
01
21h
Program/Selective Program Page 8
001000
10
22h
Lock/Selective Lock Page 8
001000
11
23h
Set Protection Bit/ Selective Set Protection Bit of Page 8
001001
00
24h
General Read Page 9
001001
01
25h
Program/Selective Program Page 9
001001
10
26h
Lock/Selective Lock Page 9
001001
11
27h
Set Protection Bit/ Selective Set Protection Bit of Page 9
001010
00
28h
General Read Page 10
001010
01
29h
Program/Selective Program Page 10
001010
10
2Ah
Lock/Selective Lock Page 10
001010
11
2Bh
Set Protection Bit/ Selective Set Protection Bit of Page 10
001011
00
2Ch
General Read Page 11
001011
01
2Dh
Program/Selective Program Page 11
001011
10
2Eh
Lock/Selective Lock Page 11
001011
11
2Fh
Set Protection Bit/ Selective Set Protection Bit of Page 11
001100
00
30h
General Read Page 12
001100
01
31h
Program/ Selective Program Page 12
001100
10
32h
Lock/ Selective Lock Page 12
001100
11
33h
Set Protection Bit/ Selective Set Protection Bit of Page 12
001101
00
34h
General Read Page 13
001101
01
35h
Program/ Selective Program Page 13
001101
10
36h
Lock/ Selective Lock Page 13
001101
11
37h
Set Protection Bit/ Selective Set Protection Bit of Page 13
001110
00
28h
General Read Page 14
001110
01
39h
Program/ Selective Program Page 14
001110
10
3Ah
Lock/ Selective Lock Page 14
001110
11
3Bh
Set Protection Bit/ Selective Set Protection Bit of Page 14
001111
00
3Ch
General Read Page 15
001111
01
3Dh
Program/ Selective Page 15
001111
11
3Eh
Lock/ Selective Lock Page 15
001111
11
3Fh
Set Protection Bit/ Selective Set Protection Bit of Page 15
Page 19
010011
00
4Ch
Battery Check
Page 26
011010
00
68h
Battery Charge
Page 31
011111
01
7Dh
MSP Access (Program Page 31)
Page 40
101000
00
A0h
General Read Page 40
101000
01
A1h
Program/ Selective Program Page 40
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
(1)
18
(1)
The TMS37157 will not respond to a Battery Charge Command. The RF has to stay on after transmitting the Write Address. To end the
battery charge command any other command can be performed.
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Table 2. Valid Command and Page Field Combinations (Command) (continued)
WRITE ADDRESS
Page 41
Page 42
Page 43
Page 44
Page 45
Page 46
Page 47
Page 48
Page 49
Page 50
Page 51
101000
10
A2h
Lock/ Selective Lock Page 40
101000
11
A3h
Set Protection Bit/ Selective Set Protection Bit of Page 44
101001
00
A4h
General Read Page 41
101001
01
A5h
Program/ Selective Program Page 41
101001
10
A6h
Lock/ Selective Lock Page 41
101001
11
A7h
Set Protection Bit/ Selective Set Protection Bit of Page 41
101010
00
A8h
General Read Page 42
101010
01
A0h
Program/ Selective Program Page 42
101010
10
AAh
Lock/ Selective Lock Page 42
101010
11
ABh
Set Protection Bit/ Selective Set Protection Bit of Page 42
101011
00
ACh
General Read Page 43
101011
01
ADh
Program/ Selective Program Page 43
101011
10
AEh
Lock/ Selective Lock Page 43
101011
11
AFh
Set Protection Bit/ Selective Set Protection Bit of Page 43
101100
00
B0h
General Read Page 44
101100
01
B1h
Program/ Selective Program Page 44
101100
10
B2h
Lock/ Selective Lock Page 44
101100
11
B3h
Set Protection Bit/ Selective Set Protection Bit of Page 44
101101
00
B4h
General Read Page 45
101101
01
B5h
Program/ Selective Program Page 45
101101
10
B6h
Lock/ Selective Lock Page 45
101101
11
B7h
Set Protection Bit/ Selective Set Protection Bit of Page 45
101110
00
B8h
General Read Page 46
101110
01
B9h
Program/ Selective Program Page 46
101110
10
BAh
Lock/ Selective Lock Page 46
101110
11
BBh
Set Protection Bit/ Selective Set Protection Bit of Page 46
101111
00
BCh
General Read Page 47
101111
01
BDh
Program/ Selective Program Page 47
101111
10
BEh
Lock/ Selective Lock Page 47
101111
11
BFh
Set Protection Bit/ Selective Set Protection Bit of Page 47
110000
00
C0h
General Read Page 48
110000
01
C1h
Program/ Selective Program Page 48
110000
10
C2h
Lock/ Selective Lock Page 48
110000
11
C3h
Set Protection Bit/ Selective Set Protection Bit of Page 48
110001
00
C4h
General Read Page 49
110001
01
C5h
Program/ Selective Program Page 49
110001
10
C6h
Lock/ Selective Lock Page 49
110001
11
C7h
Set Protection Bit/ Selective Set Protection Bit of Page 49
110010
00
C8h
General Read Page 50
110010
01
C9h
Program/ Selective Program Page 50
110010
10
CAh
Lock/ Selective Lock Page 50
110010
11
CBh
Set Protection Bit/ Selective Set Protection Bit of Page 50
110011
00
CCh
General Read Page 51
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Table 2. Valid Command and Page Field Combinations (Command) (continued)
WRITE ADDRESS
Page 52
Page 53
Page 54
Page 55
110011
01
CDh
Program/ Selective Program Page 51
110011
10
CEh
Lock/ Selective Lock Page 51
110011
11
CFh
Set Protection Bit/ Selective Set Protection Bit of Page 51
110100
00
D0h
General Read Page 52
110100
01
D1h
Program/ Selective Program Page 52
110100
10
D2h
Lock/ Selective Lock Page 52
110100
11
D3h
Set Protection Bit/ Selective Set Protection Bit of Page 52
110101
00
D4h
General Read Page 53
110101
01
D5h
Program/ Selective Program Page 53
110101
10
D6h
Lock/ Selective Lock Page 53
110101
11
D7h
Set Protection Bit/ Selective Set Protection Bit of Page 53
110110
00
D8h
Lock/ Selective Lock Page 54
110110
01
D9h
Program/Selective Page 54
110110
10
DAh
Lock/Selective Lock Page 54
110110
11
DBh
Set Protection Bit/ Selective Set Protection Bit of Page 54
110111
00
DCh
General Read Page 55
110111
01
DDh
Program/Selective Page 55
110111
10
DEh
Lock/Selective Lock Page 55
110111
11
DFh
Set Protection Bit/ Selective Set Protection Bit of Page 55
Read Formats
The Read phase starts with each deactivation of the transmitter, which is detected by the transponder, because
the transponder resonance circuit RF amplitude drops. The transponder starts with transmission of 16 Pre-bits.
During this phase the resonance circuit resonates with the low bit transmit frequency (fL). During transmission of
the read data or response, the resonance circuit frequency is shifted between the low bit transmit frequency (fL)
and the high bit transmit frequency (fH).
The typical data low bit frequency is 134.7 kHz; the typical data high bit frequency is 123.7 kHz. The low and
high bits have different durations, because each bit takes 16 RF cycles to transmit.
Figure 6 shows the FM principle used. Regardless of the number of low and high bits, the transponder response
duration is always less than 15 ms.
Data encoding is done in NRZ mode (Non Return to Zero). The clock is derived from the RF carrier by a
divide-by-16 function.
0
1
0
1
134.7 kHz
123.7 kHz
134.7 kHz
123.7 kHz
129.3 µs
118.8 µs
Figure 6. FM Principle Used in Read Function of Transponders
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After a charge phase only, having no write phase, the transponder discharges its capacitor at the end of the
pre-bit phase, which results in no response. If a valid function was detected during the write phase, the complete
read data format is transmitted. The content of the read data format depends on the previously executed
function.
When the last bit has been sent, the capacitor is discharged. During discharge no charge-up is possible.
A sufficiently long read time (tRD) must be provided to ensure that the complete read data format can be
received.
During the response (read) phase, the transponder transmits 96 bits of data, formatted as described below. The
content of the response depends on which page was addressed.
All read data starts with a 16-bit preamble followed by an 8-bit start byte (7Eh), and ends with the 8-bit Read
Address and 16-bit Read Frame BCC. All parts of the read data are transmitted LSB first.
The Read Address byte comprises a 2-bit Status field, which is transmitted first and contains status information,
and a 6-bit Page field, which contains page and additional status information. The contents of the Status field
depend on which page is being addressed.
Table 3. Overview of Read Data Format Content
READ DATA FORMAT BYTE
Page
4
5
6
7
8
9
1
Sel. Address
Page 2
Man. Code
Serial No.
Serial No.
Serial No.
2
Sel. Address
Page 2
Man. Code
Serial No.
Serial No.
Serial No.
3
Sel. Address
Page 2
Man. Code
Serial No.
Serial No.
Serial No.
8
Page 2
Page 8
Page 8
Page 8
Page 8
Page 8
9
Page 2
Page 9
Page 9
Page 9
Page 9
Page 9
10
Page 2
Page 10
Page 10
Page 10
Page 10
Page 10
11
Page 2
Page 11
Page 11
Page 11
Page 11
Page 11
12
Page 2
Page 12
Page 12
Page 12
Page 12
Page 12
13
Page 2
Page 13
Page 13
Page 13
Page 13
Page 13
14
Page 2
Page 14
Page 14
Page 14
Page 14
Page 14
15
Page 2
Page 15
Page 14
Page 14
Page 14
Page 14
19
Battery level
‘00000000’
‘00000000’
‘00000000’
‘00000000’
‘00000000’
31
MSP Data
MSP Data
MSP Data
MSP Data
MSP Data
MSP Data
40
Page 2
Page 40
Page 40
Page 40
Page 40
Page 40
41
Page 2
Page 41
Page 41
Page 41
Page 41
Page 41
42
Page 2
Page 42
Page 42
Page 42
Page 42
Page 42
43
Page 2
Page 43
Page 43
Page 43
Page 43
Page 43
44
Page 2
Page 44
Page 44
Page 44
Page 44
Page 44
45
Page 2
Page 45
Page 45
Page 45
Page 45
Page 45
46
Page 2
Page 46
Page 46
Page 46
Page 46
Page 46
47
Page 2
Page 47
Page 47
Page 47
Page 47
Page 47
48
Page 2
Page 48
Page 48
Page 48
Page 48
Page 48
49
Page 2
Page 49
Page 49
Page 49
Page 49
Page 49
50
Page 2
Page 50
Page 50
Page 50
Page 50
Page 50
51
Page 2
Page 51
Page 51
Page 51
Page 51
Page 51
52
Page 2
Page 52
Page 52
Page 52
Page 52
Page 52
53
Page 2
Page 53
Page 53
Page 53
Page 53
Page 53
54
Page 2
Page 54
Page 54
Page 54
Page 54
Page 54
55
Page 2
Page 55
Page 55
Page 55
Page 55
Page 55
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Table 4 to Table 5 show the valid Status and Page field combinations supported by the TMS37157.
Table 4. Valid Responses, If Page 1 to 3 is Addressed
READER
Write Function
General Read Page 1 to 3
Selective Read Page 1 to 3
Program/Selective Program
Page 1 to 3
Lock / Selective Lock
Page 1 to 3
TRANSPONDER
Write Address
Read Address
000001
……….
000011
00
000001
……….
000011
11
000001
……….
000011
01
000001
……….
000011
10
Valid Responses
000001
……….
000011
00
Read unlocked Page 1…3
10
Read locked Page 1…3
000001
……….
000011
00
Read unlocked Page 1…3
10
Read locked Page 1…3
000001
……….
000011
01
Programming done on Page 1…3
10
Read locked Page 1…3 programming not executed
00
Read unlocked Page 1…3, programming not
executed (field strength too low)
000000
01
Programming Page 1…3 done, but possibly not
reliable
000001
……….
000011
10
Read locked Page 1…3
00
Read unlocked Page 1…3, locking not execute
(field strength too low)
000000
00
Read unlocked Page 1…3, locking not correctly
executed
10
Read locked Page 1…3, but locking possibly not
reliable
Table 5. Valid Responses, if Page 8 to 15 is Addressed
READER
Write Function
General Read Page 8…15
Program/ Sel. Program
Page 8...15
Lock/ Selective Lock
Page 8…15
Set/ Selective Set Protection
Bit
Page 8…15
TRANSPONDER
Write Address
Read Address
001000
………
001111
00
001000
………
001111
01
001000
………
001111
001000
………
001111
10
11
00
Read unlocked Page 8…15
10
Read locked Page 8…15
001000
………
001111
01
Page 8…15 is locked, programming not executed
10
Page 40…55 is locked, programming not executed
00
Page 8…15 is unlocked, programming not
executed (field strength too low)
0000000
01
Programming Page 8…15 done, but possibly not
reliable
001000
………
001111
10
Read locked Page 8…15
00
Read unlocked Page 8…15, locking not executed
(field strength too low)
0000000
00
Read unlocked Page 8…15, locking not correctly
executed
10
Read locked Page 8…15, but locking possibly not
reliable
00
Read unlocked Page 8…15, Protection bit was not
set (field strength too low)
001000
………
001111
0000000
22
Possible Responses
001000
………
001111
10
Read locked Page 8…15, Protection bit was not
set (field strength too low)
11
Protection Bit of Page 8...15 was set
11
Setting of Protection bit was executed, but possibly
not reliable
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Table 6. Valid Responses, If Battery Check (Page 19) is Addressed
READER
Write Function
TRANSPONDER
Write Address
Read Page 19
(Battery Check)
010011
Read Address
00
010011
Valid Responses
00
Read unlocked Page 19
Table 7. Valid Responses if MSP Access (Page 31) is Addressed
READER
Write Function
TRANSPONDER
Write Address
011111
Read Address
01
Program Page 31
(MSP Access)
011111
000000
Possible Responses
01
MSP Access execution O.K.
00
SPI Programming failed
00
MSP Access execution failed
01
MSP Access execution failed
Table 8. Valid Responses, if Page 40 to 55 is Addressed
READER
Write Function
TRANSPONDER
Write Address
Read Address
General Read Page
40…55
101000
………
110110
00
Program/ Sel. Program
Page 40...55
101000
………
110110
01
Lock/ Selective Lock
Page 40…55
Set/ Selective Set
Protection Bit
Page 40…55
101000
………
110110
101000
………
110110
10
11
Possible Responses
101000
………
110110
00
Read / unlocked Page 40…55
10
Read / locked Page 40…55
101000
………
110110
01
Programming done on Page 40…55
10
Page 40…55 is locked, programming not executed
00
Page 40…55 is unlocked, programming not
executed (field strength too low)
0
01
Programming Page 40…55 done, but possibly not
reliable
101000
………
110110
10
Read locked Page 40…55
00
Read unlocked Page 40…55, locking not executed
(field strength too low)
0000000
00
Read unlocked Page 40…55, locking not correctly
executed
10
Read locked Page 40…55, but locking possibly not
reliable
00
Read unlocked Page 40…55, Protection bit was
not set (field strength too low)
10
Read locked Page 40…55, Protection bit was not
set (field strength too low)
11
Protection Bit of Page 40...55 was set
11
Setting of Protection bit was executed, but possibly
not reliable
101000
………
110110
000000
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LF TELEGRAMS – MEMORY ACCESS
Following sections show the structure of the Write - and Read Formats for the Memory Access through the Low
Frequency Interface.
Write to Transponder
Read Commands
The write format of the General Read command is shown in Figure 7.
Write
Adress
CHARGE
Read or
discharge
Figure 7. General Read/Get Status Command
The write format of the Selective Read command is shown in Figure 8.
Write
Adress
CHARGE
Read or
discharge
Selective
Frame BCC
Adress
Figure 8. Selective Read
Program Commands
The write format of the general program command is shown in Figure 9.
CHARGE
ttx
Write
Adress
CHARGE
tprog
Frame BCC
Write data
Read or
discharge
Figure 9. General Program Command
The write format of the selective program command is shown in Figure 10.
CHARGE
ttx
Write
Adress
Selective
Adress
Write data
Frame BCC
CHARGE
tprog
Read or
discharge
Figure 10. Selective Program Command
Lock and Protect Commands
The write format of the Lock/Protect command is shown in Figure 11.
CHARGE
ttx
Write
Adress
Frame BCC
CHARGE
tprog
Read or
discharge
Figure 11. General Lock/Protect
The write format of the Selective Lock/Protect command is shown in Figure 12.
CHARGE
ttx
Write
Adress
Selective
Adress
Frame BCC
CHARGE
tprog
Read or
discharge
Figure 12. Selective Lock/Protect
Lock and Protect commands share the same write format.
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Read From Transponder (Response)
The write format of the General Read command is shown in Figure 7.
Transponder Response Format of the General Read command is shown in Figure 13 and Figure 14. The
Response Format is the same for Read, Program and Lock Commands.
PREBITS
START
Selective
IDT
Man
Serial Number
READ
ADDR.
READ
FRAME BCC
16 Bits
8 Bits
8 Bits
8 Bits
8 Bits
24 Bits
8 Bits
16 Bits
LSB
96 Bits
DISCHARGE
MSB
Figure 13. Read Data Format of Page 1, 2, 3
PREBITS
START
Selective
User Data
Read
ADDR.
Read
FRAME BCC
16 Bits
8 Bits
8 Bits
40 Bits
8 Bits
16 Bits
LSB
96 Bits
DISCHARGE
MSB
Figure 14. Read Data Format of Page 8–15 and Page 40 to 55
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LF TELEGRAMS – SPECIAL FUNCTION
MSP Access
The MSP Access command allows transfer of LF data to and from the MSP 430 microcontroller via the
TMS37157 Analog Front End. The microcontroller handles data transfers using the following SPI commands:
• MSP Read Data From PCU (Data In)
• MSP Write Data To PCU (Data Out)
Write Data Format
The write format of the MSP Access command is shown in Figure 15.
WRITE
ADDRESS
CHARGE
8 Bits
LSB
DATA 5
48 Bits
10
111110
MSB
LSB MSB
Write MSP Data
DATA 0
WRITE
FRAME BCC
CHARGE
READ OR
DISCHARGE
16 Bits
Page 31
Figure 15. LF Write Format – MSP Access Command
Read Data Format
The read format of the MSP Access command is shown in .
LF Read Format – MSP Access Command
PREBITS
START
16 Bits
8 Bits
LSB
MSP DATA
48 Bits
READ
ADDRESS
8 Bits
96 Bits
READ
FRAME BCC
DISCHARGE
16 Bits
MSB
Flow of MSP Access Data Handling
The following sequence is needed to implement an MSP Access command:
• The TMS37157 detects that an MSP Access command has been received and wakes the Microcontroller
(e.g. MSP430).
• The Microcontroller reads the status using the SPI command Get Status.
• The MSP access request is detected and the data are requested by the Microcontroller. Data bytes are
transferred to the Microcontroller using the SPI command MSP Read Data from PCU.
• The data bytes are processed and actions executed, as necessary.
• If necessary, the Microcontroller sends response data bytes back to the TMS37157, using the SPI command
MSP Write Data to PCU.
• After the TMS37157 has detected removal of LF power, the response data bytes are sent back to the base
station.
NOTE
The LF field must be present throughout the above sequence (except the last step),
otherwise a malfunction of the TMS37157 may occur.
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Battery Check
When a Battery Check command has been received, the Control Unit compares the battery voltage with two
pre-defined thresholds and responds with the result of the comparison.
Write Data Format
The write format of the Battery Check command is shown in Figure 16.
CHARGE
READ OR
DISCHARGE
WRITE
ADDRESS
LSB
00
MSB
110010
Page 19
Figure 16. LF Write Format – Battery Check Command
Read Data Format
The read format of the Battery Check command is shown in Figure 17.
PREBITS
START
BATTERY
LEVEL
ZERO BITS
READ
ADDR.
READ FRAME BCC
16 Bits
8 Bits
8 Bits
40 Bits
8 Bits
16 Bits
DISCHARGE
96 Bits
Figure 17. LF Read Format – Battery Check Command
Whenever the TMS37157 receives a Battery Check command, it compares the battery voltage with two
pre-defined thresholds – 2.1 V and 2.9 V - and responds with the result of the comparison in accordance with
Figure 18.
0
0
0
0
0
0
V
V
FULL
2.9 V
VV=00:
VBAT < 2.1 V
VV=01:
2.1 V < VBAT < 2.9 V
VV=11:
VBAT > 2.9 V
EMPTY
2.1 V
Figure 18. Battery Voltage Comparison
Battery Charge
When a Battery Charge Command has been received the TMS37157 applies a voltage of about 3.4 V to VBAT.
The charge current depends mainly on the antenna of the LC Tank Circuit and the Field Strength of the Base
Station. The TMS37157 does not answer to a Battery Charge Command. The LF Field has to remain on after
transmitting the telegram. The telegram format corresponds to a Read Page 26 Command.
The charging of the battery can be ended by any other command.
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Write Data Format
The write data format of the Battery Charge Command is shown in Figure 19.
CHARGE
WRITE
AD DRESS
LSB
00
Charge…..
MSB
010110
Page 26
Figure 19. Battery Charge Write Command
SPI COMMANDS
The serial interface for communication between a Microcontroller and the TMS37157 is a synchronous SPI
interface which uses clock and data lines to transfer data in bytes. The Microcontroller can use its on-chip
hardware USART to implement this interface protocol, which allows efficient Microcontroller operation and
simplifies software development. The USART should be used in synchronous SPI (Serial Peripheral Interface)
mode, with the Microcontroller designated as the master for all bi-directional communications.
The TMS37157 uses a 3 wire SPI Communication Interface (SIMO, SOMI, CLK). No Enable is necessary. For
Synchronization the BUSY Output of the TMS37157 can be used.
SPI Communication Structure
SPI communications can only be initiated by the Microcontroller if the TMS37157 is ready to receive. This is
indicated by a low level on the BUSY line – when the first byte is received via the SIMO line, BUSY goes high. A
short BUSY low pulse confirms that a byte has been correctly received. After this low pulse, the next byte of the
protocol can be sent. If the SPI command requires it, the TMS37157 will then send byte-wise response data via
the SOMI line. Each byte sent by the TMS37157 will be confirmed by a short BUSY low pulse. After successful
communication, the BUSY line will go from high to low after the last transferred byte and remain low (see
Figure 20).
CLK
SIMO
LEN
CMD
DATA
DATA
SOMI
BUSY
DATA
OK
Figure 20. SPI Communication
The initial rising of the busy line happens latest after the 3rd rising edge of the SPI Clock. This indicates that the
Front End starts to process the incoming data. It remains high until the Front End is ready with processing of the
8-bit data. After this a low busy pulse (min 30 μs, typ.50 μs, max. 70 μs) indicates to the Microcontroller that the
next data can be sent.
The time the busy line stays high varies depending on the operations the Front End has to perform. The
maximum duration is 30ms after all bytes on the SIMO are received. Sending out data on SOMI line depends
mainly on the speed of the SPI-Clock. The next SPI Data must be sent within tBusyhigh=10ms. If the next data is
not applied within tBusyhigh the SPI command is interrupted.
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If an error occurs during SPI communication, the BUSY line remains at the level it was when the error occurred.
The following three types of error are possible:
Error 1:
The TMS37157 stops communication via its SPI interface and indicates this by taking BUSY low. The microcontroller
has not finished, but BUSY remains low.
Error 2:
The TMS37157 is ready to continue communication via its SPI interface and indicates this by taking BUSY high. The
microcontroller has finished, however, and expects BUSY to remain low. After max. 50ms = tBusyhigh an internal
watchdog shuts down the whole TMS73157 IC.
Error 3:
If the TMS37157 receives an invalid command it performs a power down command. This command results in a shut
down of the whole TMS37157 IC.
SPI Protocol Structure
The first 8 bits sent by the microcontroller contain telegram length information (LEN), which defines the number
of following bytes to be transferred via the SIMO line. It is the number of bytes excluding the LEN-byte.
The second 8 bits sent by the microcontroller contain the Command byte (CMD). The first (most significant) two
bits of the Command byte determine which of the four different types the command is, and the six least
significant bits contain various flags associated with the command (see Figure 21).
Three types of command are available:
• Transponder Access Command (TAC)
• Enhanced Command (EC)
• Reserved Command (RC) – for future use.
C
C
X
X
X
X
MSB
X
X
LSB
CC=00:
Transponder Access Command (TAC)
CC=01:
n.a.
CC=10:
Enhanced Commands (EC)
CC=11:
Reserved Commands (RC)
X:
Don’t care
Figure 21. SPI Command Byte Overview
NOTE
All SPI bits that are either not used or are marked with an "X" are reserved for future
use and must be "0".
Transponder Access Commands
The microcontroller can access the contents of the Transponder Memory by sending the TMS37157 a
Transponder Access Command via the SIMO line.
The two most significant bits of the Command byte determine the Transponder Access Command and the six
least significant bits are don’t care. If the contents of the Command byte are invalid for the device configuration,
an error condition will be indicated via the BUSY line.
This command is followed by the same Write Address used in LF data transmissions and, if necessary, is
followed by further data bytes (e.g. Selective Address, Data). The TMS37157 responds by transferring the
relevant transponder data to the microcontroller via the SOMI line (see Figure 20.)
In all cases, responses to Transponder Access Commands are sent without the 16-bit preamble, start byte and
BCC that are normally used in LF data transmissions.
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Optional
SIMO
LEN
CMD
Sel.
Addr.
WA
DATA
DATA *
SOMI
DATA
DATA
Figure 22. TAC Protocol Overview
NOTE
The format of Transponder Access Commands format is identical to the format used
for the LF communication. The optional data has to be added as it is described in the
LF section.
In the following figure some examples protocols are shown.
The protocol of the General Read of Page 1 is shown in Figure 23.
SIMO
LEN
CMD
WA
LSByte
SEL. ADDR.
SOMI
IDT
MAN.
SER. NO.
MSByte
SER. NO.
SER. NO.
RD ADDR.
Figure 23. TAC Format – General Read Page 1
Table 9. Example:
Length:
0x02
Two bytes to follow.
Command:
0x00
= 00 000000 (binary)
00
000000
Write Address:
0x04
= Transponder Access Command (TAC)
= don’t care
= 000001 00 (binary)
000001
00
Sel. Address:
0x00
= Page 1
= General Read
Selective address is 0x00
The 7 byte response depends on the Transponder Memory content.
SIMO = 0x02 0x00 0x04
SOMI = Sel.Ad. IDT Man. Ser.# Ser.# Ser.# Rd.Ad.
The protocol of the Selective Read of Page 1 is shown in Figure 24.
SIMO
LEN
CMD
WA
SEL.
ADDR.
LSByte
SEL.
ADDR.
SOMI
IDT
MAN.
SER. NO.
MSByte
SER. NO.
SER. NO.
RD ADDR.
Figure 24. TAC Format – Selective Read Page 1
Example:
The 7 byte response depends on the Transponder Memory content.
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Table 10. Example:
Length:
0x03
Three bytes to follow.
Command:
0x00
= 00 000000 (binary)
00
000000
Write Address:
0x07
= Transponder Access Command (TAC)
= don’t care
= 000001 11 (binary)
000001
11
Sel. Address:
0x03
= Page 1
= Selective Read
Selective address is 0x03
SIMO = 0x03 0x00 0x07 0x03
SOMI = Sel.Ad. IDT Man. Ser.# Ser.# Ser.# Rd.Ad.
The protocol for the read of Page 19 (Battery Check) is shown in Figure 25.
SIMO
LEN
CMD
WA
Battery
level
SOMI
WA
0x00
0x00
0x00
0x00
0x00
RA
= 010011 00
Read Page
Page 19
Figure 25. TAC Format – Read Page 19 Battery Check
SIMO = 0x02 0x00 0x4C
Enhanced Commands
The microcontroller can access the contents of the Transponder Memory by sending the TMS37157 a
Transponder Access Command via the SIMO line.
The two most significant bits of the Command byte determine the Enhanced Commands, Bit 6 to Bit 3 determine
which Enhanced Command should be performed. The two least significant buts determine certain functions
connected to the command. If the contents of the command byte are invalid for the device configuration, an error
condition will be indicated via the BUSY line.
The TMS37157 supports a number of Enhanced Commands (EC) which are used to transfer commands and
data between the microcontroller and the TMS37157 (e.g. to perform a CRC calculation or trim the antenna).
Command Byte
SIMO
1
0
M
M
M
M
MSB
F
F
LSB
M:
Mode Bits.
F:
Flag Bits.
Figure 26. EC Command Byte Contents
The list contained in Table 11 shows the various Enhanced Commands supported by the TMS37157.
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Table 11. Supported EC Commands
MMMM = 0
= ‘0000’:
CRC Calculation Command
MMMM = 1
= ‘0001’:
Reserved For Future Use
MMMM = 2
= ‘0010’:
Antenna Trimming with Programming Command
MMMM = 3
= ‘0011’:
Reserved For Future Use
MMMM = 4
= ‘0100’:
Reserved For Future Use
MMMM = 5
= ‘0101’:
Oscillator ON Command
MMMM = 6
= ‘0110’:
Reserved For Future Use
MMMM = 7
= ‘0111’:
CLKA ON command
MMMM = 8
= ‘1000’:
Reserved For Future Use
MMMM = 9
= ‘1001’:
Reserved For Future Use
MMMM = 10
= ‘1010’:
Antenna trimming without Program. Command
MMMM = 11
= ‘1011’:
Reserved for Future Use
MMMM = 12
= ‘1100’:
MSP Read/Write Data from/to Control Unit
MMMM = 13
= ‘1101’:
MSP Read Control Unit Status
MMMM = 14
= ‘1110’:
Power Down Command
MMMM = 15
= ‘1111’:
Reserved For Future Use
CRC CALCULATION COMMAND
The CRC Calculation command allows the microcontroller to use the transponder in the TMS37157 to perform a
CRC16 calculation (instead of having to implement it in software). The contents of the command byte and two
sample protocols are shown in Figure 27 to Figure 29.
Command Byte
SIMO
1
0
0
0
0
0
0
MSB
S
LSB
S=0:
Start Value is 3791
S=1:
Send Start Value
Figure 27. EC CRC Calculation Command Byte
SIMO
LEN
CMD
# BYTE
LSByte
MSByte
DATA
DATA
LSByte MSByte
CRC
SOMI
CRC
Figure 28. EC Format – CRC Calculation With Start Value "3791"
NOTE
The second byte of the CRC Calculation command (# of Bytes) refers only to data
bytes and does not include the start bytes.
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SIMO
LEN
CMD
# BYTE
LSByte
MSByte LSByte
START
START
MSByte
DATA
DATA
SOMI
LSByte
MSByte
CRC
CRC
Figure 29. EC Format – CRC Calculation Command Including Start Value
ANTENNA TRIMMING WITHOUT PROGRAMMING COMMAND
The Antenna Trimming without Programming command enables faster trimming than the Antenna Trimming with
Programming command. Using this command the trimming capacitors are controlled, but the trim configuration is
not stored in the configuration EEPROM. The contents of the command byte and a sample protocol are shown
below.
NOTE
In order to use the Antenna Trimming Without Programming function, the trimming
capacitors must first be programmed to the OFF state using the Antenna Trimming
With Programming command.
Command Byte
SIMO
1
0
1
0
1
0
0
MSB
1
LSB
Figure 30. EC Format – Antenna Trimming Without Programming Command Byte
SIMO
LEN
CMD
DATA
SOMI
Figure 31. EC Format – Antenna Trimming Without Programming Command Protocol
ANTENNA TRIMMING WITH PROGRAMMING
The Antenna Trimming with Programming command can be used to switch in or out each of the on-chip trimming
capacitors. The command programs the trim settings and saves them in a non-volatile EEPROM. The contents of
the command byte and a sample protocol are shown below.
Command Byte
SIMO
1
0
0
0
1
0
0
MSB
1
LSB
Figure 32. EC Format – Antenna Trimming With Programming Command Byte
SIMO
LEN
CMD
DATA
SOMI
Figure 33. EC Format – Antenna Trimming Command Protocol
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OSCILLATOR ON COMMAND
The Oscillator command can be used to enable the TMS37157 LC tank (connected to RF1). The output of this
oscillator is presented at the TMS37157 CLKA pin and can be used as a time reference by the microcontroller or
for measurements for antenna trimming. The contents of the command byte and a sample protocol are shown in
Figure 34 and Figure 35.
NOTE
Once the oscillator has been enabled using the Oscillator On command, its output
must be switched to the CLKA pin using the CLKA On command.
This function needs a minimum battery voltage of 2.3V .
Command Byte
SIMO
1
0
0
1
0
1
C
MSB
C
LSB
CC=00: Oscillator Off
CC=01: Oscillator On (134 kHz)
CC=10: Oscillator/4 On (134/4 kHz)
Figure 34. EC Format – Oscillator Command Byte
SIMO
LEN
CMD
SOMI
Figure 35. EC Format – Oscillator Command Protocol
CLKA ON COMMAND
The CLKA command can be used to switch oscillator output to the CLKA pin. This is necessary if during
production no trimming is performed and the microcontroller has to trim the LC circuit of the TMS37157. It is
recommended to connect CLKA to a Timer clock input of a microcontroller. For a precise time base a crystal or a
resonator is needed at the microcontroller.
If CLKA is not needed after trimming, it can be switched off to avoid the noise influences of the CLKA signal line.
The contents of the command byte and a sample protocol are shown in Figure 36 and Figure 37.
Command Byte
SIMO
1
0
0
1
1
1
X
MSB
C
LSB
C=0:
CLKA Off
C=1:
CLKA On
Figure 36. EC Format – CLKA Command Byte
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SIMO
LEN
CMD
SOMI
Figure 37. EC Format – CLKA Command Protocol
MSP READ DATA FROM CU (DATA IN)
If the TMS37157 receives a MSP Access Command it signalizes it by a high Pulse at busy and by setting VBATI.
The busy signal could be used as interrupt to wake a microcontroller from Low Power Mode.
The MSP Read Data from CU command can be used to transfer the decoded LF data from the Control Unit in
the TMS37157 to the microcontroller. This command returns always 6 bytes to the MSP430. The contents of the
command byte and a sample protocol are shown in Figure 38 and Figure 39.
Command Byte
SIMO
1
0
1
1
0
0
0
MSB
0
LSB
Figure 38. EC Format – MSP Read Data From CU Command Byte
SIMO
LEN
CMD
SOMI
DATA 0
DATA 1
DATA 2
DATA 3
DATA 4
DATA 5
Figure 39. EC Format – MSP Read Data From CU Command Protocol
MSP WRITE DATA TO CU (DATA OUT)
The MSP Write Data to CU command enables the microcontroller to transfer data to the Control Unit in the
TMS37157 for LF transmission. The contents of the command byte and a sample protocol are shown in
Figure 40 to Figure 41.
Command Byte
SIMO
1
0
1
1
0
0
0
MSB
1
LSB
Figure 40. EC Format – MSP Write Data to CU Command Byte
SIMO
LEN
CMD
DATA 0
DATA 1
DATA 2
DATA 3
DATA 4
DATA 5
STATUS
SOMI
Figure 41. EC Format – MSP Write Data to CU Command Protocol
NOTE
To complete the Data out command the RF Field must be present at least for 500μs
after the last SPICLK.
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MSP READ CU STATUS (INFO)
The Info command enables the microcontroller to check the Control Unit in the TMS37157 to see if any
commands/data are waiting to be processed.
The contents of the command byte and a sample protocol are shown in Figure 42 to Figure 43. The contents of
the mask field can be ignored.
Figure 44 shows the contents of the status byte sent as a response.
Command Byte
SIMO
1
0
1
1
0
1
0
MSB
0
LSB
Figure 42. EC Format – MSP Read Status From CU Command Byte
SIMO
LEN
CMD
STATUS
SOMI
MASK
Figure 43. EC Format – MSP Read Status From CU Protocol
Status Byte
SIMO
0
0
0
0
0
0
S
MSB
S
LSB
SS=01:
Push
SS=10:
MSP Access
Figure 44. EC Format – MSP Read Status From CU Status Byte
POWER DOWN
The Power Down command enables the microcontroller to shut down the TMS37157 after all operations have
been completed. After detecting this command, the Control Unit in the TMS37157 opens SW2 and SW5 and
clears the push button detection flip-flop. All TMS37157 functions except push button detection are not powered
and the TMS73157 enters a standby condition. The contents of the command byte and a sample protocol are
shown in Figure 45 and Figure 46.
Command Byte
SIMO
1
0
1
1
1
0
MSB
0
0
LSB
Figure 45. EC Format – Power Down Command Byte
SIMO
LEN
CMD
SOMI
Figure 46. EC Format – Power Down Protocol
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TEST COMMANDS
The Test Interface is needed to tune the resonance frequency to 134.2kHz during production e.g. at the end of
line test.
It comprises two input pins (TEN and TCLK) and one bi-directional pin (TDAT). The CLK signal is used to strobe
data into and out of the TMS37157, as shown in the typical timing diagram in Figure 47. Communication via the
Test Interface is activated when a valid voltage is applied to VCL and TCLK and TEN are taken high. After
waiting a suitable time (the Probe Test Reset period) TCLK can be taken low and the Write Phase started (TEN
having already been taken low). Probe Test Write Data is read into the TMS37157 on each rising edge of TCLK.
Taking TEN high starts the Read Phase, during which the TMS37157 places new data on the TDAT line on
every rising edge of TCLK (data valid on the falling edge of TCLK).
Probe Test Reset
Probe Test Read Data
Probe Test Write Data
VCL
tTclk = 1/fTclk
tTclkh
tTclkl
TCLK
TDAT
tTds
tTdh
tTdd
TEN
tTres
tTrc
Figure 47. Test Interface Timing
Resonance Frequency Measurement
The first step in the antenna trimming process is to measure the resonance frequency of the antenna circuit. For
optimum energy transfer, trimming should be performed with VCL=4V, which is high enough to ensure an LF
response, but below the limitation voltage.
The resonance frequency of the antenna circuit can be measured using Probe Test Mode PTx18 (see Figure 48).
After Probe Test Reset, the 6-bit PT Mode (0x18) and the 8-bit Password (0x5A) are shifted into the TMS37157,
followed by 131 clock cycles. The measurement phase begins when TEN is taken high, whereupon the TCLK
pulse triggers an oscillation in the antenna circuit.
The resulting oscillation will decay at a rate determined by the Q-factor of the antenna circuit, and a clock signal
will appear at TDAT as soon as oscillation starts. The measurement time should last at least 10 clock cycles and
the average period of one cycle calculated from that. The average resonance frequency is simply the reciprocal
of the average resonance period. If longer measurement times are required, the resonance circuit oscillation can
be stimulated again with additional TCLK pulses.
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VCL
PT Mode (0x18)
(6 clocks)
(8 clocks)
LSB
Period
Duration
>= 10
PT Password (0x5A)
(147 clocks)
MSB LSB
Period
Duration
>= 10
Period
Duration
>= 10
MSB
TCLK
TDAT
0
0
0
1
1
0
0
1
0
1
1
0
1
0
TEN
RF1
Figure 48. Test Interface Timing – Resonance Frequency Measurement
Trimming EEPROM Programming
The second step in the frequency trimming process is to program the 7-bit trim word in the trimming EEPROM.
The trimming EEPROM can be programmed using Probe Test Mode PTx14 (see Figure 49). After Probe Test
Reset, the 6-bit PT Mode (0x14) and the 8-bit Password (0x5A) are shifted into the TMS37157, followed by 8 trim
bits. Programming begins when TEN is taken high.
NOTE
Trimming EEPROM Programming requires that 8 trim bits are clocked in, however,
only the 7 LSB’s after functional – the state of the MSB has no effect.
The result of the programming process should be verified re-measuring the resonance frequency, and the whole
process repeated until optimum performance achieved.
PT Mode (0x14)
PT Password (0x5A)
(6 clocks)
Trim Bits
(8 clocks)
(8 clocks)
LSB
( 1 cl o ck )
VCL
MSBLSB
Programming
(11 msec)
MSBLSB
MSB
TCLK
7 Trim Bits
TDAT
0
0
1
0
1
0
0
1
0
1
1
0
1
0
T1 T2 T3 T4 T5 T6 T7
0
TEN
Figure 49. Test Interface Timing – Trimming EEPROM Programming
38
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Modulation Frequency Check
During LF transmissions a FSK signal is transmitted. The resonance frequency of the trimmed antenna circuit
(fL) represents a low bit and high bits are represented by a lower frequency (fH), which is achieved by switching
in a Modulation Capacitor in parallel with the antenna resonance circuit. This frequency can be measured in the
same way as the normal resonance frequency, but using Probe Test Mode 0x16 instead of 0x18.
CRC Calculation
A Cyclic Redundancy Check (CRC) generator is used in the TMS37157 during receipt and transmission of data
to generate a 16-Bit Block Check Character (BCC), applying the CRC-CCITT algorithm as shown in Figure 51.
The CRC generator consists of 16 shift register cells with 3 exclusive OR (Xor) Gates. The first Xor gate (X16)
combines the input of the CRC generator with the output of the shift register (LSB first) and feeds back to the
input of the shift register. The other two Xor gates combine certain cell outputs (X12, X5) with the output of the
first Xor Gate and feed into the next cell input.
The CRC Generator is initialized with the value 0x3791 as shown in Figure 50).
MSB
0
LSB
0
1
1
3
0
1
1
7
1
1
0
0
1
0
9
0
0
1
1
Figure 50. Initial CRC Value 0x3791
Figure 51. CRC Generator Block Schematic
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TMS37157
SWRS083A – SEPTEMBER 2009 – REVISED NOVEMBER 2009
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The CRC generation is started with the first shifted bit, received during write phase RXCK, RXDT. After reception
of program or lock command and the additional bits, including the write frame BCC, the CRC Generator content
is compared to 0x0000 (CRC_OK).
During read function CRC generation is started after transmission of the start byte (0x7E). After the read data (6
bytes) and the read address byte, the CRC generator content is shifted out using the CRC generator as a normal
shift register (SHIFT signal). DATA OUT represents the BCC which is added to read data and read address. The
BCC format is one Word with LSB shifted out first.
From a mathematics point of view, the data, which are serially shifted through the CRC generator with LSB first,
are multiplied by 16 and divided by the CRC-CCITT generator polynomial:
P(X) =X16 + X12 + X5 + 1
(1)
The remainder from this division is the Read Frame Block Check Character (Read Frame BCC).
The interrogator control unit has to use the same algorithm to generate the Write Frame BCC and to check the
Read Frame BCC received from the transponder. The response is checked by shifting the Read Frame BCC
through the CRC generator in addition to the received data; the content of the CRC generator must be zero after
this action.
Typically the CRC generator is realized in the Base Stations by means of software and not hardware. The
algorithm can be handled on a bit-by-bit basis (see Figure 52) or by using look-up tables.
Figure 52. Routine - Generate Block Check Character Bit by Bit
40
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Application Circuit
Only a few additional components are required for using the TMS37157. The recommended application circuits
are shown in Figure 53 and Figure 54.
In Figure 53 a typical application of a sensor with a data logger is shown. The Microcontroller is connected to a
battery and can wake the TMS37157 to write data into the EEPROM of the TMS37157. The data can be read out
through the LF Interface of the TMS37157. This application may also be used for powering the μC out of the RF
Field if a battery is not an applicable solution. The battery has to be replaced by a big enough capacitor which is
used as a buffer during the LF communication.
Figure 53. Application Circuit With μC Directly Connected to Battery
In Figure 54 a typical application of a Low Power Sensor with an external interrupt is shown. The μC VCC is
connected to the VBATI output. If an external interrupt at Push occurs the TMS37157 initializes and powers up
the μC by applying 3 V to VBATI. The μC can perform a measurement store the data in the EEPROM of the
TMS37157 and send a power down command to the TMS37157, which switches off VBATI, resulting in an
overall power consumption of the whole system of about 60 nA (TMS37157 is in Push Detection Mode).
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Figure 54. Application Circuit With μC Connected to VBATI output of TMS37157
42
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PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
TMS37157IRSARG4
ACTIVE
QFN
RSA
16
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
37157
I
(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)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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