
CHAPTER 19 CAN CONTROLLER
User’s Manual U16541EJ4V0UD
775
(21) CAN0 message configuration register m (C0MCONFm)
The C0MCONFm register is used to specify the type of the message buffer and to set a mask.
(1/2)
After reset: Undefined
R/W
Address: See Table 19-16.
7
6
5
4
3
2
1
0
C0MCONFm
OWS
RTR
MT2
MT1
MT0
0
MA0
OWS
Overwrite control bit
0
The message buffer
Note that has already received a data frame is not overwritten by a newly received
data frame. The newly received data frame is discarded.
1
The message buffer that has already received a data frame is overwritten by a newly received data
frame.
Note
The “message buffer that has already received a data frame” is a receive message buffer whose the
C0MCTRLm.DN bit has been set to 1.
Remark
A remote frame is received and stored, regardless of the setting of the OWS and DN bits. A
remote frame that satisfies the other conditions (ID matches, the RTR bit = 0, the
C0MCTRLm.TRQ bit = 0) is always received and stored in the corresponding message buffer
(interrupt generated, DN flag set, the C0MDLCm.MDLC0 to C0MDLCm.MDLC3 bits updated,
and recorded to the receive history list).
RTR
Remote frame request bit
Note
0
Transmit a data frame.
1
Transmit a remote frame.
Note
The RTR bit specifies the type of message frame that is transmitted from a message buffer defined
as a transmit message buffer. Even if a valid remote frame has been received, the RTR bit of the
transmit message buffer that has received the frame remains cleared to 0. Even if a remote frame
whose ID matches has been received from the CAN bus with the RTR bit of the transmit message
buffer set to 1 to transmit a remote frame, that remote frame is not received or stored (interrupt
generated, DN flag set, the MDLC0 to MDLC3 bits updated, and recorded to the receive history list).
MT2
MT1
MT0
Message buffer type setting bit
0
Transmit message buffer
0
1
Receive message buffer (no mask setting)
0
1
0
Receive message buffer (mask 1 set)
0
1
Receive message buffer (mask 2 set)
1
0
Receive message buffer (mask 3 set)
1
0
1
Receive message buffer (mask 4 set)
Other than above
Setting prohibited