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Rev.1.02 Jul 01, 2005 page 218 of 314
REJ09B0126-0102
M16C/6N Group (M16C/6NL, M16C/6NN) 18. CAN Module
Under development
This document is under development and its contents are subject to change.
18.12 Return from Bus Off Function
When the protocol controller enters bus off state, it is possible to make it forced return from bus off state by
setting the RetBusOff bit in the C0CTLR register to “1” (Force return from bus off). At this time, the error
state changes from bus off state to error active state. If the RetBusOff bit is set to “1”, the C0RECR and
C0TECR registers are initialized and the State_BusOff bit in the C0STR register is set to “0” (CAN module
is not in error bus off state). However, registers of the CAN module such as C0CONR register and the
content of each slot are not initialized.
18.13 Time Stamp Counter and Time Stamp Function
When the C0TSR register is read, the value of the time stamp counter at the moment is read. The period of
the time stamp counter reference clock is the same as that of 1 bit time that is configured by the C0CONR
register. The time stamp counter functions as a free run counter.
The 1 bit time period can be divided by 1 (undivided), 2, 4 or 8 to produce the time stamp counter reference
clock. Use the TSPreScale bit in the C0CTLR register to select the divide-by-n value.
The time stamp counter is equipped with a register that captures the counter value when the protocol
controller regards it as a successful reception. The captured value is stored when a time stamp value is
stored in a reception slot.
18.14 Listen-Only Mode
When the RXOnly bit in the C0CTLR register is set to "1", the module enters listen-only mode.
In listen-only mode, no transmission, such as data frames, error frames, and ACK response, is performed
to bus.
When listen-only mode is selected, do not request the transmission.