13
13-9
Ver.0.10
CAN MODULE
13.2 CAN Module Related Registers
(1) RBO (Return Bus Off) bit (D4)
Setting this bit to 1 clears the Receive Error Counter (CAN0REC) and Transmit Error Counter
(CAN0TEC) and forcibly places the CAN module into an error active state. This bit is cleared
when an error active state is entered.
Note:
After clearing the error counter, transmission becomes possible when 11 consecutive
recessive bits are detected on the CAN bus.
(2) TSR (Time Stamp Counter Reset) bit (D5)
Setting this bit to 1 clears the value of the CAN Time Stamp Counter Register (CAN0TSTMP) to
H'0000. This bit is cleared when the value of the CAN Time Stamp Counter Register
(CAN0TSTMP) is cleared to H'0000.
(3) TSP (Time Stamp Prescaler) bits (D6, D7)
These bits select the count clock source for the time stamp counter.
Note:
Do not change settings of TSP bits while CAN is operating (CAN Status Register CRS bit
= 0).
(4) FRST (Forcible Reset) bit (D11)
When the FRST bit is set to 1, the CAN module is separated from the CAN bus regardless of
whether or not the CAN module is communicating and the protocol control unit is reset.
Note 1:
To restart CAN communication, the FRST and RST bits must be cleared to 0.
Note 2:
If the FRST bit is set to 1 during communication, the CTX pin output goes high
immediately after that. Therefore, setting the FRST bit to 1 while transmitting CAN frame
may cause a CAN bus error.
(5) BCM (BasicCAN Mode) bit (D12)
By setting this bit to 1, the CAN module can be operated in BasicCAN mode.
Operation during BasicCAN mode
In BasicCAN mode, two local slots-slots 14 and 15-are used as double buffers, and receive
frames that are found matching to the ID by acceptance filtering are stored alternately in
slots 14 and 15. Used for this acceptance filtering when slot 14 is active (next receive frame
to be stored in slot 14) are the ID set for slot 14 and local mask A, and those used when slot
15 is active are the ID set for slot 15 and local mask B. Two types of frames-data frame and
remote frame-can be received in this mode.