RFSENT Frame Analysis & SENT Bus Protocol Analyzer Tool
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Introduction : The SENT (Single Edge Nibble Transmission) protocol is a point to point, unidirectional protocol used in automotive sensor applications, where structured nibble based frames deliver time based encoded sensor data.
SENT Frame Structure
| Field | Size | Purpose/Description |
|---|---|---|
| Synchronization/Calibration Pulse | 56 ticks (Variable time) | A fixed-length pulse of 56 ticks that allows the receiver to calculate the message’s tick time and synchronize its clock. |
| Status and Communication Nibble | 4 bits | A 4-bit nibble that provides status information or is used for communication. Its pulse length is between 12 and 27 ticks, representing a value of 0 to 15. |
| Data Nibbles | 24 bits | A series of up to six data nibbles. Each one encodes 4 bits of data, with its pulse duration varying from 12 to 27 ticks, corresponding to a value from 0 to 15 (data value + 12). |
| Checksum Nibble | 4 bits | A 4-bit Cyclic Redundancy Check (CRC) nibble at the end of the frame. It’s calculated over all the nibbles except the status nibble and is used to verify data integrity. |
| Optional Pause Pulse | Variable | A pulse that can be added between frames to separate messages. Its length can vary between 12 and 768 ticks. |
SENT Protocol Data logger tool
| Manufacturers | Product/features |
|---|---|
| Vector Informatik | The VN1630A and VN1640A hardware interfaces along with required software (CANoe or CANalyzer with the .SENT option) provide multiple channels that can be configured for SENT, allowing for the simultaneous analysis of several sensors. |
| Intrepid Control Systems | The ValueCAN 4 Industrial is a multi-purpose tool that includes dedicated I/O channels that can be configured for SENT protocol analysis and transmission. It uses “Vehicle Spy 3” software. |
| Pico Technology | PicoScope with SENT Decoder : As an oscilloscope-based tool, it excels at analyzing the analog characteristics of the SENT signal. |
| Teledyne LeCroy | Motor Drive Analyzer / Automotive Oscilloscopes : It uses SENT Trigger and Decode Option in the software. |
| iSYSTEM | Hardware: iC5700 and other BlueBox On-Chip Analyzers.; Tools from iSYSTEM connect directly to the microcontroller’s debug interface (e.g., JTAG, DAP), allowing them to trace the internal processing of the SENT data within the ECU. |
Summary: A SENT bus protocol analyzer tool enables introspection of the ultra low cost and deterministic sensor interface. It captures individual nibble transmissions, decoding timing fields and validating sensor communications in automotive systems.
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