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M16C/5L Group, M16C/56 Group
23.2.4
CAN Operation Mode (Excluding Bus-Off State)
CAN operation mode is used for CAN communication.
When the CANM bit in the C0CTLR register is set to 00b, the CAN module enters CAN operation mode.
Then bits RSTST and HLTST in the C0STR register are set to 0. Do not change the value of the CANM
bit until these bits are set to 0.
If 11 consecutive recessive bits are detected after entering CAN operation mode, the CAN module is in
the following states:
• The CAN module becomes an active node on the network that enables transmission and reception
of CAN messages.
• Error monitoring of the CAN bus, such as receive and transmit error counters, is performed.
During CAN operation mode, the CAN module may be in one of the following three submodes,
depending on the status of the CAN bus:
• Idle mode: Transmission or reception is not being performed.
• Receive mode: A CAN message sent by another node is being received.
• Transmit mode: A CAN message is being transmitted. The CAN module may receive its own
message simultaneously when self-test mode 0 (TSTM bit in the C0STR register = 10b) or self-test
mode 1 (TSTM bit = 11b) is selected.
Figure 23.35 shows the submode in CAN operation mode.
TRMST, RECST: Bits in the C0STR register
Figure 23.35 Submode in CAN Operation Mode
R01UH0127EJ0110 Rev.1.10
Sep 01, 2011
Transmission
starts
Transmission
completed
Transmit mode
TRMST = 1
RECST = 0
Idle mode
TRMST = 0
RECST = 0
SOF
detected
Reception
completed
Lost in arbitration
23. CAN Module
Receive mode
TRMST = 0
RECST = 1
Page 602 of 803
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