C515C_9711 Datasheet, PDF (148/268 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

On-Chip Peripheral Components
C515C
Bit
Function
LEC
Last error code
This field holds a code which indicates the type of the last error occurred on the
CAN bus. If a message has been transferred (reception or transmission) without
error, this field will be cleared. Code “7” is unused and may be written by the
microcontroller to check for updates.
LEC2-0
0 00
0 01
0 10
0 11
1 00
1 01
1 10
Error
Description
No Error –
Stuff Error More than 5 equal bits in a sequence have occurred
in a part of a received message where this is not
allowed.
Form Error A fixed format part of a received frame has the
wrong format
Ack Error The message this CAN controller transmitted was
not acknowledged by another node.
Bit1 Error
During the transmission of a message (with the
exception of the arbitration field), the device wanted
to send a recessive level (“1”), but the monitored bus
value was dominant.
Bit0 Error
During the transmission of a message (or
acknowledge bit, active error flag, or overload flag),
the device wanted to send a dominant level (“0”), but
the monitored bus value was recessive. During
busoff recovery this status is set each time a
sequence of 11 recessive bits has been monitored.
This enables the microcontroller to monitor the
proceeding of the busoff recovery sequence
(indicating the bus is not stuck at dominant or
continously disturbed).
CRC Error The CRC check sum was incorrect in the message
received.
Note :Reading the SR when an interrupt is pending, resets the pending interrupt request.
Semiconductor Group
6-85
1997-11-01