Chapter 14 Freescale’s Scalable Controller Area Network (S12MSCANV3)
MC9S12XDP512 Data Sheet, Rev. 2.11
672 Freescale Semiconductor
14.5.2 Bus-Off Recovery
The bus-off recovery is user configurable. The bus-off state can either be left automatically or on user
request.
For reasons of backwards compatibility, the MSCAN defaults to automatic recovery after reset. In this
case, the MSCAN will become error active again after counting 128 occurrences of 11 consecutive
recessive bits on the CAN bus (See the Bosch CAN specification for details).
If the MSCAN is configured for user request (BORM set in Section 14.3.2.2, “MSCAN Control Register
1 (CANCTL1)”), the recovery from bus-off starts after both independent events have become true:
128 occurrences of 11 consecutive recessive bits on the CAN bus have been monitored
BOHOLD in Section 14.3.2.14, “MSCAN Miscellaneous Register (CANMISC) has been cleared
by the user
These two events may occur in any order.