ID 0 ID 1 ID2 ID3 ID 4 ID 5 P0 P1
Start
Bit
Stop
Bit
O pti on al
Leng th
Co n tr o l
Bit s
ID Fie ld
O pti on a l
Pa rity
Bit s
SDEL
1..4 Tbit
SYNCH BREAK
13+(0...7) Tbit
SYNCH FIELD
10 Tbit
ID FIELD
10 Tbit
START BIT
STOP BIT
0
1
01
0
1
01
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LIN
1647
SPNU563A–March 2018
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Serial Communication Interface (SCI)/ Local Interconnect Network (LIN)
Module
29.3.1.5 Header Generation
Automatic generation of the LIN protocol header data stream is supported without CPU interaction. The
CPU pr the DMA will trigger a message header generation and the LIN state machine will handle the
generation itself. A master node initiates header generation on CPU or DMA writes to the IDBYTE in the
LINID register. The header is always sent by the master to initiate a LIN communication and consists of
three fields: break field, synchronization field, and identification field, as seen in Figure 29-15.
Figure 29-15. Message Header in Terms of T
bit
• The break field consists of two components:
– The synchronization break (SYNCH BREAK) consists of a minimum of 13 (dominant) low bits to a
maximum of 20 dominant bits. The synch break length may be extended from the minimum with the
3-bit SBREAK value in the LINCOMP register.
– The synchronization break delimiter (SDEL) consists of a minimum of 1 (recessive) high bit to a
maximum of 4 recessive bits. The delimiter marks the end of the synchronization break field. The
synch break delimiter length depends on the 2-bit SDEL value in the LINCOMP register.
• The synchronization field (SYNCH FIELD) consists of one start bit, byte 0x55, and a stop bit. It is used
to convey T
bit
information and resynchronize LIN bus nodes.
• The identifier field’s ID byte may use six bits as an identifier, with optional length control (see
Note:Optional Control Length Bits), and two optional bits as parity of the identifier. The identifier parity
is used and checked if the PARITY ENA bit is set. If length control bits are not used, then there can be
a total of 64 identifiers plus parity. If neither length control or parity are used there can be up to 256
identifiers. See Figure 29-16 for an illustration of the ID field.
Figure 29-16. ID Field
NOTE: Optional Control Length Bits
The control length bits only apply to LIN standards prior to LIN 1.3. IDBYTE field conveys
response length information if compliant to standards earlier than LIN1.3. The SCIFORMAT
register stores the length of the response for later versions of the LIN protocol.
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