SENT (protocol)


The SAE J2716 SENT protocol is a point-to-point scheme for transmitting signal values from a sensor to a controller. It is intended to allow for transmission of high resolution data with a low system cost.

Hardware

The SENT protocol is a one-way, asynchronous voltage interface which requires three wires: a signal line, a supply voltage line and a ground line.

Software

Data is transmitted in units of 4 bits for which the interval between two falling edges of the modulated signal with a constant amplitude voltage is evaluated. A SENT message is 32 bits long and consists of the following components: 24 bits of signal data that represents 2 measurement channels of 3 nibbles each, 4 bits for CRC error detection, and 4 bits of status/communication information. Optionally, data can be transferred in 20 bit messages composed of a single 12 bit measurement, a 4 bit CRC error checksum, and a 4 bit status/communication field.
The image below shows the SENT signal described above. In this case a Pause Pulse is used. The Pause Pulse compensates for the varying length of the messages.

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