L9669 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'L9669' PDF : 13 Pages View PDF
L9669
1.3 Error Management
Ten different errors on the physical buslines can be distinguished:
N
Type of Errors
Severity
RX
TX
Errors caused by damage of the datalines or isolation
1 CANH wire interrupted (floating or tied to termination)
0
0
2 CANL wire interrupted (floating or tied to termination)
0
0
3 CANH short circuit to VS (overvoltage condition)
1
1
4 CANL short circuit to GND (permanently dominant)
2
0
5 CANH short circuit to GND (permanently recessive)
0
2
6 CANL short circuit to VS (overvoltage condition)
1
1
7 CANL shorted to CANH
2
2
Errors caused by misbehaviour of transceiver stage
8 CANH short circuit to VCC (permanently dominant)
2
0
9 CANL short circuit to VCC (permanently recessive)
0
2
Errors caused by defective protocol unit
10 CANH, CANL driven dominant for more than 1.3 ms
2
2
Not all of these errors leads to a breakdown of the whole communication. So the errors can be categorized into
“negligible” (severity 0), “problematic” (severity 1) and “severe” (severity 2).
Negligible Errors
Transmitter
Error 1, 2, 4 or 8:
Receiver
Error 1, 2, 5 or 9:
In all cases data still can be transmitted in differential mode.
In all cases data still can be received in differential mode.
Problematic Errors
Transmitter
Error 3 or 6:
Data are transmitted using the remaining dataline (single wire).
Receiver
Error 3 or 6:
Data are received using the remaining dataline (single wire).
Severe Errors
Transmitter
Error 5 or 9:
Error 7:
Error 10:
Receiver
Error 7:
Error 4 or 8:
Error 10:
Data are transmitted using the remaining dataline after short circuit detection.
Data are transmitted on CANH or CANL after overcurrent was detected.
Transmission is terminated (fail safe).
Data are received on CANH or CANL after detection of permanent dominant state.
Data are received on CANH or CANL after short circuit was detected.
Data are received normally, error is detected by protocol unit.
Upon any error in normal or RXonly mode the NERR output will be forced LOW and released after error recovery.
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