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SURFACE VEHICLE

INFORMATION REPORT

J2716™

APR2016

Issued 2007-04

Revised 2016-04

Superseding J2716 JAN2010

(R) SENT - Single Edge Nibble Transmission for Automotive Applications

RATIONALE

1. Clarified clock variation refers to variation in clock tick time.

2. New appendix for High Speed 12 bit Sensors.

3. Changes for initialization and non-usage of serial message.

4. Changes to support option for independent 5V supply in sensor

5. Serial message cycle changed to ≤ 64 messages for greater flexibility and to allow more time for diagnostic

information.

6. Clarification to EMC Susceptibility testing guidelines for Erroneous SENT frames which remain undetected by the

SENT CRC

7. Added Appendix A.6 Temperature Sensor requirements

8. Added APPENDIX E

9. Added APPENDIX G for recommended connector

10. Created APPENDIX H (SENT Data Frame Formats) and moved generic sensor requirements from APPENDIX A

to APPENDIX H

11. Changes to support higher current sensors

12. Added E.3 Error Messages and Signals

13. Added A.7 Position Sensors and Combined Position Temperature Sensors

14. Added Overview of SENT standard structure (3.2)

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TABLE OF CONTENTS 
 SCOPE ....................................................................................................................................................................... 5 
1  Overview .................................................................................................................................................................... 5 
 
 REFERENCES ........................................................................................................................................................... 6 
1  Applicable Documents ............................................................................................................................................... 6 
1.1  SAE Publications ........................................................................................................................................................ 6 
1.2  Other Publications ...................................................................................................................................................... 6 
 
 DEFINITION OF TERMS ........................................................................................................................................... 6 
1  Glossary ..................................................................................................................................................................... 6 
2  Overview of SENT standard structure ....................................................................................................................... 8 
 
 ACRONYMS, ABBREVIATIONS, AND SYMBOLS ................................................................................................. 10 
 
 SENT SYSTEM REQUIREMENTS .......................................................................................................................... 10 
1  General Requirements ............................................................................................................................................. 10 
2  Message Definitions ................................................................................................................................................. 11 
2.1  Transmission Sequence ........................................................................................................................................... 11 
2.2  Transmission Properties of Calibration/Synchronization Pulse ............................................................................... 12 
2.3  Transmission Properties of Nibble Pulse ................................................................................................................. 12 
2.4  Status and Communication Nibble ........................................................................................................................... 13 
2.5  Checksum Nibble ..................................................................................................................................................... 17 
2.6  Pause Pulse (Optional) ............................................................................................................................................ 17 
3  Transmission and Reception of Message ................................................................................................................ 18 
3.1  Transmission of Message ........................................................................................................................................ 18 
3.2  Adjustment of Received Message Nibble Lengths .................................................................................................. 18 
3.3  Received Message Diagnostics ............................................................................................................................... 19 
3.4  Reset ........................................................................................................................................................................ 21 
4  Checksum Nibble Details ......................................................................................................................................... 21 
4.1  Errors Detected and Not Detected by Checksum .................................................................................................... 21 
4.2  CRC Implementation ................................................................................................................................................ 24 
 
 SENT PHYSICAL LAYER OPERATION .................................................................................................................. 25 
1  Normal Communication Mode and Transmission Rate ........................................................................................... 25 
2  Clock Tolerance ....................................................................................................................................................... 26 
2.1  Transmitter–Receiver Communications ................................................................................................................... 26 
3  Electrical Interface Requirements ............................................................................................................................ 27 
3.1  Transmitter Driver Requirements ............................................................................................................................. 27 
3.2  Receiver Input Requirements................................................................................................................................... 33 
3.3  Bus Wiring Harness and ECU Connectors .............................................................................................................. 35 
4  ESD Immunity .......................................................................................................................................................... 35 
5  EMC Testing Requirements ..................................................................................................................................... 36 
6  Fault Protection Modes ............................................................................................................................................ 36 
 
 CONFIGURATION SHORTHAND ........................................................................................................................... 36 
1  Shorthand Definition ................................................................................................................................................. 36 
 
 NOTES ..................................................................................................................................................................... 37 
1  Revision Indicator ..................................................................................................................................................... 37 
 
   
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Appendix A  Recommended application specific protocols ...................................................................................... 38 
Appendix B  Checksum examples ............................................................................................................................ 51 
Appendix C  Testing guidelines ................................................................................................................................. 55 
Appendix D  Serial channel message IDS ................................................................................................................ 58 
Appendix E  Common sensor definitions .................................................................................................................. 76 
Appendix F  Fast channel multiplexing ..................................................................................................................... 93 
Appendix G  SENT connectors ............................................................................................................................... 101 
Appendix H   SENT data frame formats ................................................................................................................... 103 
Appendix I  Alternative receiver circuit .................................................................................................................. 118 
 
Figure 3.2.1-1  SENT standard structure and transmission layers ................................................................................. 9 
Figure 5.2.1-1  Example encoding scheme for two 12 bit signals ................................................................................ 11 
Figure 5.2.3-1  Example nominal nibble times .............................................................................................................. 12 
Figure 5.2.3-2  Continued example nibble values ........................................................................................................ 12 
Figure 5.2.4.1-1  Construction of short serial data message from 16 SENT messages.................................................. 13 
Figure 5.2.4.2-1  Construction of enhanced serial data message from 18 SENT messages .......................................... 14 
Figure 5.2.4.2-2  Enhanced serial message format with 12-bit data field and 8-bit message id ..................................... 15 
Figure 5.2.4.2-3  Enhanced serial message format with 16-bit data field and 4-bit message id ..................................... 15 
Figure 5.2.4.3-1  Order of the message bits, 24-bit message used for CRC generation ................................................ 16 
Figure 5.3.2-1  Quantisation of sampled and calibrated nibble .................................................................................... 18 
Figure 5.3.3.1-1  Error pattern for successive calibration pulse detection ....................................................................... 19 
Figure 5.3.3.1-2  Successive calibration pulse detection ................................................................................................. 20 
Figure 6.2.1-1  Illustration of clock error accumulation as given in table 6.2.1-1. ......................................................... 26 
Figure 6.3-1  Example SENT system interface circuit topology ................................................................................. 27 
Figure 6.3.1-1  Example SENT shaped waveform transmitter output .......................................................................... 28 
Figure 6.3.1-2  SENT transmit pulse parameters ......................................................................................................... 28 
Figure 6.3.1-3  SENT system interface circuit topology for a regulated 5v power supply of the transmitter by  
the receiver ........................................................................................................................................... 30 
Figure 6.3.1-4  SENT system interface circuit topology for an independent 5v power supply in the receiver with 
identical signal ground line and power ground line .............................................................................. 30 
Figure 6.3.1-5  SENT system interface circuit topology for an independent 5v power supply in the receiver with 
separate signal ground line and power ground line ............................................................................. 31 
Figure 6.3.2-1  Legacy SENT receiver interface circuit topology.................................................................................. 33 
Figure 6.3.2-2  Recommended SENT system interface circuit topology ...................................................................... 33 
Figure 6.3.2-3  Example alternative SENT system interface circuit topologiy .............................................................. 34 
Figure C.1.2.1-1  Error time examples ............................................................................................................................. 55 
Figure C.1.2.2-1  Worst case age for signal as received by ECU .................................................................................... 56 
Figure C.2-1  Supply current ripple test setup ............................................................................................................ 57 
Figure D.6-1  Example: serial message cycle with 14 messages (table D.6-1) is transmitted continuously.   
Serial message cycle can be captured within 64 messages. ............................................................... 72 
Figure D.7-1  Start-up phase of the sensor and the ecu ............................................................................................ 73 
Figure E.2.1.1-1  Nominal characteristic function of a sensor (with 12-bit data values) .................................................. 78 
Figure E.2.1.2-1  Partitioning of measurement data ranges and mapping onto SENT data values (for illustration) ....... 80 
Figure E.2.2.1-1  Default temperature characteristic function (for illustration) ................................................................. 82 
Figure E.2.2.2-1  High temperature characteristic function (for illustration) ..................................................................... 83 
Figure E.2.3-1  Ratio transfer function .......................................................................................................................... 85 
Figure E.2.4.1.1-1  Application with default Y
1
, Y
2
 .............................................................................................................. 87 
Figure E.2.4.1.2-1  Application with sensor-specific Y
1
, Y
2
 ................................................................................................. 87 
Figure G.1.1.1-1  Assignment example of the electrical signals to the contact numbers (SENT ak connector) ............ 101 
Figure H.1-1  Format and data channels of sensors with two fast channels ............................................................ 106 
Figure H.2-1  Format and data channels of sensors with one fast channel ............................................................. 107 
Figure H.3.1-1  Structure of the high-speed SENT frame ........................................................................................... 109 
Figure H.4-1  Format and data channels of sensors with fast channel 1 and secure sensor information ............... 111 
Figure H.5-1  Format and data channels of single sensors with one 12-bit fast channel ........................................ 113 
Figure H.6-1  Format and data channels of sensors with 14-bit fast channel 1 and 10-bit fast channel 2 .............. 115 
Figure H.7-1  Format and data channels of sensors with 16-bit fast channel 1 and 8-bit fast channel 2 ................ 117 
Figure I.2-1  Worst case transmitter with reference circuit topology ....................................................................... 119 
Figure I.2-2  Procedure to guarantee that pulse shapes of alternative circuit will always stay within the limits  
given by the tolerances of the reference circuit .................................................................................. 120 
 
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Table 5.2.4-1  Status and communication nibble description ...................................................................................... 13 
Table 5.2.4.3-1  Undetected 3 and 4 bit errors ............................................................................................................... 16 
Table 5.4.1-1  Bit flip patterns over two nibbles not detectable using the crc polynomial ........................................... 21 
Table 5.4.1-2  Checksum missed detection rate, edge shift between two nibbles   
(valid frames only, recommended implementation).............................................................................. 22 
Table 5.4.1-3  Checksum missed detection rate, asymmetrical edge shift offset by 1 between two nibbles   
(valid frames only, recommended implementation).............................................................................. 23 
Table 6.2.1-1  Communication clock tolerance............................................................................................................ 26 
Table 6.3.1-1  Transmitter driver requirements ........................................................................................................... 29 
Table 6.3.1-2  Independent 5v powered transmitter requirements .............................................................................. 31 
Table 6.3.1-3  Independent 5v supply high power transmitter additional requirements .............................................. 32 
Table 6.3.2-1  General receiver input requirements .................................................................................................... 34 
Table 6.3.2-2  Discrete receiver component values .................................................................................................... 35 
Table 6.3.2-3  Receiver power supply requirements ................................................................................................... 35 
Table 7.1-1  SENT configuration shorthand definition .............................................................................................. 36 
Table A.2.1-1  Data channels for maf sensors ............................................................................................................. 38 
Table A.2.3.1-1  Short serial message format message ids for mass air flow sensor serial data .................................. 40 
Table A.2.3.1-2  Error codes for message id f, short serial message format mass air flow sensor serial data .............. 40 
Table A.5.1-1  Overview of pressure sensor frame formats and protocols .................................................................. 43 
Table A.6.2.1  Interpretation of n-bit temperature data ................................................................................................ 46 
Table A.6.3-1  Overview of temperature sensor frame formats and protocols ............................................................ 47 
Table A.6.3-2  Overview of temperature sensor frame formats and protocols using fast channel multiplexing .......... 48 
Table B.1-1  Example 4-bit checksum calculations, legacy implementation ............................................................ 51 
Table B.1-2  Example 4-bit checksum calculations, recommended implementation ................................................ 51 
Table B.1-3  Example 4-bit crc calculation by polynominal division ......................................................................... 52 
Table B.1-4  Example 4-bit crc verification by polynominal division ......................................................................... 53 
Table B.2-1  Example checksum calculations, 6-bit crc ............................................................................................ 54 
Table C.1.2.1-1  Number of wrong frames for error time ................................................................................................ 56 
Table C.2-1  Supply current ripple test setup circuit parameters .............................................................................. 57 
Table D.1-1  Serial message channel 8-bit message ids .......................................................................................... 58 
Table D.2-1  Serial message channel 4-bit message ids .......................................................................................... 60 
Table D.3-1  SENT revision codes ............................................................................................................................ 60 
Table D.4.1-1  SENT sensor types ............................................................................................................................... 61 
Table D.4.2-1  SENT sensor classes ........................................................................................................................... 69 
Table D.5-1  Definition of error and status messages, transmitted over the serial channel ..................................... 70 
Table D.6-1  Example: sub-set of message ids that are used by a sensor within one serial message cycle ........... 72 
Table D.8-1  Manufacturers codes ............................................................................................................................ 74 
Table D.9-1  Transmission of ascii characters over $90 to $97: encoding example ................................................ 75 
Table E.1.2-1  Examples: measurement data and signaling data regions of fast and supplementary channel data .. 76 
Table E.1.3-1  Error indicators / specific messages / initialization message ............................................................... 77 
Table E.2.1.2-1  Partitioning of the signal data space with default Y
1
 and Y
2
 ................................................................. 79 
Table E.2.1.4-1  Default Y
1
 and Y
2
 values ...................................................................................................................... 80 
Table E.2.1.5-1  Transmission of generic linear transfer characteristic node values X
I
 with 12-bit X
D,I
 ......................... 81 
Table E.2.2-1  Overview of temperature transfer characteristic functions ................................................................... 82 
Table E.2.2.1-1  Transfer function parameters for default linear temperature data channels ........................................ 82 
Table E.2.4-1  Transfer function parameters for pressure data channels ................................................................... 85 
Table E.2.4-2  Illustration of possible values for X
1
 and X
2
 for pressure data channels .............................................. 86 
Table E.2.4-3  Transmission of pressure transfer characteristic node values X
I
 with 12-bit X
D,I
 ................................ 86 
Table E.2.2.3-1  Transfer function parameters for special linear temperature data channels ........................................ 84 
Table E.2.5-1  Transfer function parameters for position data channels ..................................................................... 88 
Table E.2.5-2  Illustration of possible values for X
1
 and X
2
 for linear position data channels...................................... 88 
Table E.2.5-3  Illustration of possible values for X
1
 and X
2
 for angle data channels ................................................... 89 
Table E.2.5-4  Illustration of possible values for X
1
 and X
2
 for relative position and relative angle data channels ..... 89 
Table E.2.6-1  Transfer function parameters for linear maf data channel ................................................................... 89 
Table E.3.2-1  Setting of error messages and signals ................................................................................................. 90 
Table F.2-1  Fast channel multiplexing data frame formats examples with six data nibbles .................................... 93 
Table F.2-2  Examples for mapping of sensor data into fast channel multiplexing data frame format ..................... 94 
Table F.4-1  Allocation of the bits of the status and communication nibble .............................................................. 95 
Table F.5-1  Example of failure cases with single sensor data channel ................................................................... 97 
Table F.5-2  Example of failure cases with two sensor data channels ..................................................................... 98 
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Table F.6.1-1  Data frames with 12-bit sensor data ..................................................................................................... 99 
Table F.6.2-1  Data frames with 16-bit sensor data ..................................................................................................... 99 
Table F.6.3-1  Data frames with two sensor data channels ....................................................................................... 100 
Table F.6.4-1  Data frames with free to use data ...................................................................................................... 100 
Table G.1.1.1-1  SENT connector termination assignment ........................................................................................... 101 
Table H-1  Basic SENT frame formats, data channels and nibble orders ........................................................... 104 
Table H-2   Allocation of the bits of the status and communication nibble ............................................................ 104 
Table H.1-1  Nibble and bit orders for sensors with two 12-bit fast channels ......................................................... 106 
Table H.3.1-1  Nibble and bit orders for high-speed 12-bit sensors........................................................................... 109 
Table H.5-1  Nibble and bit orders for single sensors with one 12-bit fast channel ................................................ 112 
Table H.6-1  Nibble and bit orders for sensors with 14-bit fast channel 1 and 10-bit fast channel 2 ...................... 114 
Table H.7-1  Nibble and bit orders for sensors with 16-bit fast channel 1 and 8-bit fast channel 2 ........................ 116 
Table I.1-1  Allowed pulse shape deviation between reference receiver and alternative circuit ........................... 118 
 
1.  SCOPE 
This document defines a level of standardization in the implementation of the digital pulse scheme for reporting sensor 
information via Single Edge Nibble Transmission (SENT) encoding. This standard will allow ECU and tool manufacturers to 
satisfy the needs of multiple end users with minimum modifications to the basic design. This standard will benefit vehicle 
Original  Equipment Manufacturers  (OEMs)  by  achieving lower ECU costs due to higher industry volumes  of  the basic 
design. 
Requirements stated in this document provide a minimum standard level of performance to which all compatible ECUs and 
media shall be designed. This assures data communication among all connected devices regardless of supplier. 
This document is a communication interface specification and no to be treated as product specification. 
The intended audience includes, but is not limited to, ECU suppliers, sensor suppliers, component release engineers and 
vehicle system engineers. 
1.1  Overview 
The Single Edge Nibble Transmission encoding scheme (SENT) is intended for use in applications where high resolution 
sensor data needs to be communicated from a sensor to an Electronic Control Unit (ECU). It is intended as a replacement 
for  the  lower  resolution  methods  of  10  bit  A/D’s  and  PWM  and  as  a  simpler  low  cost  alternative  to  CAN  or  LIN.  The 
implementation assumes that the sensor is a smart sensor containing a microprocessor or dedicated logic device (ASIC) to 
create the signal. 
SENT is a unidirectional communications scheme from sensor / transmitting device to controller /receiving device which 
does not include a coordination signal from the controller/receiving device. The sensor signal is transmitted as a series of 
pulses with data encoded as falling to falling edge periods. Details of the signal encoding may vary for specific sensor 
applications described in various appendices of this specification. 
   
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