1 to 8 Data Fields
Checksum
Field
Response
+ INVERT
Modulo-256 sum
Checkbyte
ID Field
From
Header
1 to 8 Data Fields
Checksum
Field
Response
+ INVERT
Modulo-256 sum
Checkbyte
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LIN
1655
SPNU563A–March 2018
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Serial Communication Interface (SCI)/ Local Interconnect Network (LIN)
Module
29.3.1.8.4 Checksum Errors
A checksum error (CE) is detected and flagged at the receiving end if the calculated modulo-256 sum over
all received data bytes (including the ID byte if it is the enhanced checksum type) plus the checksum byte
does not result in 0xFF. The modulo-256 sum is calculated over each byte by adding with carry, where the
carry bit of each addition is added to the LSB of its resulting sum.
For the transmitting node, the checksum byte sent at the end of a message is the inverted sum of all the
data bytes (see Figure 29-22) for classic checksum implementation. The checksum byte is the inverted
sum of the identifier byte and all the data bytes (see Figure 29-23) for the LIN 2.0 compliant enhanced
checksum implementation. The classic checksum implementation should always be used for reserved
identifiers 60 to 63; therefore, the CTYPE bit will be overridden in this case. For signal-carrying-frame
identifiers (0 to 59) the type of checksum used depends on the CTYPE bit.
Figure 29-22. Classic Checksum Generation at Transmitting Node
Figure 29-23. LIN 2.0-Compliant Checksum Generation at Transmitting Node
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