UPD78F0838 Renesas Electronics Corporation., UPD78F0838 Datasheet - Page 601

• Manufacturer Part Number: UPD78F0838
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(b) Write
Caution
Cautions 1. Do not clear the RDY bit (0) during message transmission.
Caution Set IE bit and RDY bit always separately.
Caution Do not set the DN bit to 1 by software. Be sure to write 0 to bit 10.
TRQ
RDY
Clear MOW
DN
Clear DN
0
1
0
1
0
1
Set IE
0
1
0
1
0
1
Other than above
A data frame or remote frame is not stored in the message buffer.
A data frame or remote frame is stored in the message buffer.
No message frame transmitting request that is pending or being transmitted is in the message buffer.
The message buffer is holding transmission of a message frame pending or is transmitting a
message frame.
The message buffer can be written by software. The CAN module cannot write to the message
buffer.
Writing the message buffer by software is ignored (except a write access to the RDY, TRQ, DN, and
MOW bits). The CAN module can write to the message buffer.
2. Clear again when RDY bit is not cleared even if this bit is cleared.
3. Be sure that RDY is cleared before writing to the message buffer registers.
Do not set the TRQ bit and the RDY bit (1) at the same time. Set the RDY bit (1) before
setting the TRQ bit.
Follow the transmission abort process about clearing the RDY bit (0) for
redefinition of the message buffer.
Perform this confirmation by reading back the RDY bit. However, setting the
TRQ bit, clearing the DN bit, setting the RDY bit or clearing the MOW bit of the
C0MCTRLm register need not be confirmed.
MOW bit is not changed.
MOW bit is cleared to 0.
DN bit is not changed.
DN bit is cleared to 0.
Clear IE
1
0
IE bit is cleared to 0.
IE bit is set to 1.
IE bit is not changed.
Preliminary User’s Manual U19748EJ1V0UD
CHAPTER 15 CAN CONTROLLER
Message Buffer Transmission Request Bit
Message Buffer Data Updating Bit
Message Buffer Ready Bit
Setting of MOW Bit
Setting of DN Bit
Setting of IE Bit
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