TLE4998S3C Datasheet, PDF (31/36 Pages) Infineon Technologies AG – Programmable Linear Hall Sensor

TLE4998S3C
SENT Output Definition (SAE J2716)
12
SENT Output Definition (SAE J2716)
The sensor supports a basic version of the Single Edge Nibble Transmission (SENT)
protocol defined by SAE. The main difference between the standard version and its
implementation in the TLE4998 is the usage of an open drain instead of a push-pull
output.
12.1
Basic SENT Protocol Definition
The single edge is defined by a 3 unit time (UT) low pulse on the output, followed by the
high time defined in the protocol (nominal values, may vary by tolerance of internal RC
oscillator, not including analog delay of the open drain output and influence by external
circuitry, unit time programming see Section 12.2). All values are multiples of a unit time
frame concept. A transfer consists of the following parts:
• A synchronization period of 56 UT (in parallel, a new sample is calculated)
• A status nibble of 12-27 UT
• Three data nibbles of 12-27 UT (data packet 1 with a length of 36-81 UT)
• Three data nibbles of 12-27 UT (data packet 2 with a length of 36-81 UT)
• A CRC nibble of 12-27 UT
Sensor processing
compensate the sample
Output pin (physical)
transfer compensated sample
Transferred data (logical)
sync. period
Status
nibble
Data
nibble 1
high
Data
nibble 1
mid
Data
nibble 2
low
CRC
nibble
Figure 11 SENT Frame
The CRC checksum includes the status nibble and the data nibbles and can be used to
check the validity of the decoded data. The sensor is available for the next sample 90µs
after the falling edge of the end pulse. This leads to a minimum transfer time of 152 UT,
and a maximum transfer time of 272 UT per sample.
Data Sheet
31
Rev 1.1, 2009-09