NuMicro® NUC029LEE/NUC029SEE
32-bit Arm
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Cortex
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-M0 Microcontroller
Aug, 2018
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Deviation error on the sync field
When operating in Automatic Resynchronization mode, the controller will check the deviation
error on the sync field. The deviation error is checked by comparing the current baud rate with the
received sync field. Two checks are performed in parallel.
Check1: Based on measurement between the first falling edge and the last falling edge of the
sync field.
If the difference is more than 14.84%, the header error flag LINS_HERR_F (UA_LIN_SR[1])
will be set.
If the difference is less than 14.06%, the header error flag LINS_HERR_F (UA_LIN_SR[1])
will not be set.
If the difference is between 14.84% and 14.06%, the header error flag LINS_HERR_F
(UA_LIN_SR[1]) may either set or not.
Check2: Based on measurement of time between each falling edge of the sync field.
If the difference is more than 18.75%, the header error flag LINS_HERR_F (UA_LIN_SR[1])
will be set.
If the difference is less than 15.62%, the header error flag LINS_HERR_F (UA_LIN_SR[1])
will not be set.
If the difference is between 18.75% and 15.62%, the header error flag LINS_HERR_F
(UA_LIN_SR[1]) may either set or not.
Note:
The deviation check is based on the current baud rate clock. Therefore, in order to
guarantee correct deviation checking, the baud rate must reload the nominal value before each
new break reception by setting LINS_DUM_EN (UA_LIN_CTL[3]) register (It is recommend
setting the LINS_DUM_EN (UA_LIN_CTL[3]) bit before every checksum reception)
LIN header error detection
In LIN Slave function mode, when user enables the header detection function by setting the
LINS_HDET_EN (UA_LIN_CTL[1]), hardware will handle the header detect flow. If the header has
an error, the LIN header error flag LIN_HERR_F (UA_LIN_SR[1]) will be set and an interrupt is
generated if the LIN_IEN (UA_IER[8]) bit is set. When header error is detected, user must reset
the detect circuit to re-search a new frame header by writing 1 to LINS_SYNC_F (UA_LIN_SR[3])
to re-search a new frame header.
The LIN header error flag LIN_HERR_F (UA_LIN_SR[1]) is set if one of the following conditions
occurs:
Break Delimiter is too short (less than 0.5-bit time).
Frame error in sync field or Identifier field.
The sync field data is not 0x55 (Non-Automatic Resynchronization mode).
The sync field deviation error (With Automatic Resynchronization mode).
The sync field measure time-out (With Automatic Resynchronization mode).
LIN header reception time-out.