Figure 82. Lin Header Reception Timeout - STMicroelectronics ST72361 Auto Series Manual

LINSCI serial communication interface (LIN master/slave)
If the LHE flag is set, it means that:
D > 15.625%
If LHE flag is not set, it means that:
D < 16.40625%
If 15.625%  D  16.40625%, then the flag can be either set or reset depending on the
dephasing between the signal on the RDI line and the CPU clock.
●
The second check is based on the measurement of each bit time between both edges
of the synch field: this checks that each of these bit times is large enough compared to
the bit time of the current baud rate.
When LHE is set due to this error then the SCI goes into a blocked state (LSF bit is set).
LIN header time-out error
When the LIN Identifier field detection method is used (by configuring LHDM to 1) or when
LIN auto-resynchronization is enabled (LASE bit = 1), the LINSCI automatically monitors the
T
HEADER_MAX
If the entire Header (up to and including the STOP bit of the LIN identifier field) is not
received within the maximum time limit of 57 bit times then a LIN header error is signalled
and the LHE bit is set in the SCISR register.

Figure 82. LIN header reception timeout

The time-out counter is enabled at each break detection. It is stopped in the following
conditions:
●
A LIN identifier field has been received
●
An LHE error occurred (other than a timeout error).
●
A software reset of LSF bit (transition from high to low) occurred during the analysis of
the LIN synch field or
If LHE bit is set due to this error during the LIN synchr field (if LASE bit = 1) then the SCI
goes into a blocked state (LSF bit is set).
If LHE bit is set due to this error during fields other than LIN synch field or if LASE bit is reset
then the current received header is discarded and the SCI searches for a new break field.
Note on LIN header time-out limit
According to the LIN specification, the maximum length of a LIN header which does not
cause a timeout is equal to 1.4 * (34 + 1) = 49 T
T
BIT_MASTER
When checking this timeout, the slave node is desynchronized for the reception of the LIN
break and synch fields. Consequently, a margin must be allowed, taking into account the
178/279
condition given by the LIN protocol.
LIN Synch
Break
refers to the master baud rate.
Doc ID 12468 Rev 3
LIN Synch Identifier
Field
Field
T
HEADER
.
BIT_MASTER
ST72361xx-Auto