RL78/D1A User's Manual: Hardware - Renesas

Under development
Preliminary document
Specifications in this document are tentative and subject to change.
RL78/D1A CHAPTER 14 CAN CONTROLLER
Figure 14-74. Transmission Abort Processing Except for ABT Transmission
(Normal Operation Mode with ABT)
START
Clear ABTTRG bit
ABTTRG = 0?
Clear TRQ bit
Wait for 11 CAN data bits
TSTAT = 0?
Read C0LOPT register
END
Yes
Yes
Message buffer to
be aborted matches C0LOPT
register?
Yes
Transmission successful
Note
No
No
No
Transmit abort request
was successful
Note There is a possibility of starting the transmission without being aborted even if TRQ bit is cleared,
because the transmission request to protocol layer might already been accepted between 11 bits,
total of interframe space (3 bits) and suspend transmission (8 bits).
Cautions 1. Execute transmission request abort processing by clearing the TRQ bit, not the RDY
bit.
2. Before making a sleep mode transition request, confirm that there is no transmission
request left using this processing.
3. The TSTAT bit can be periodically checked by a user application or can be checked
after the transmit completion interrupt.
4. Do not execute the new transmission request including in the other message buffers
while transmission abort processing is in progress.
5 There is a possibility that contradiction is caused in the judgment whether the
transmission abort request was successful when the transmission from the same
message buffer is consecutive or only one message buffer is used. In that case,
judge it by using the history information etc. that the C0TGPT register indicates.
R01UH0317EJ0004 Rev. 0.04 930
Feb. 22, 2013