TLE4998S3 Datasheet, PDF (34/39 Pages) Infineon Technologies AG – Programmable Linear Hall Sensor

TLE4998S
SENT Output Definition (SAE J2716)
13
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.
13.1 Basic SENT Protocol Definition
• The single edge is defined by a 9-µs low pulse on the output, followed by the high
time defined in the protocol (nominal values, may vary by tolerance of internal RC
oscillator and the programming, see Section 13.2). All values are multiples of a 3-µs
unit time frame concept. A transfer consists of the following parts:A synchronization
period of 168 µs (in parallel, a new sample is calculated)
• A status nibble of 36-81 µs
• Three data nibbles of 36-81 µs (data packet 1 with a length of 108-243 µs)
• Three data nibbles of 36-81 µs (data packet 2 with a length of 108-243 µs)
• A CRC nibble of 36-81 µs
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 13 SENT Frame
The CRC checksum calculation includes the status nibble and the data nibbles. This
leads to a minimum transfer time of 456 µs, and a maximum transfer time of 816 µs per
sample.
It is important to know that the sampling time (when values are taken for temperature
compensation) here is always defined as the beginning of the synchronization period;
during this period, the resulting data is always calculated from scratch.
Data Sheet
34
V 1.0, 2008-07