
CHAPTER 19 CAN CONTROLLER
User’s Manual U16541EJ4V0UD
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(3) Transmission abort in normal operation mode with automatic block transmission (ABT)
To abort ABT that is already started, clear the C0GMABT.ABTTRG bit to 0. In this case, the ABTTRG bit
remains 1 if an ABT message is currently being transmitted and until the transmission is completed
(successfully or not), and is cleared to 0 as soon as transmission is finished. This aborts ABT.
If the last transmission (before ABT) was successful, the normal operation mode with ABT is left with the
internal ABT pointer pointing to the next message buffer to be transmitted.
In the case of an erroneous transmission, the position of the internal ABT pointer depends on the status of the
TRQ bit in the last transmitted message buffer. If the TRQ bit is set to 1 when clearing the ABTTRG bit is
requested, the internal ABT pointer points to the last transmitted message buffer (for details, refer to the
process in Figure 19-47). If the TRQ bit is cleared to 0 when clearing the ABTTRG bit is requested, the
internal ABT pointer is increased in increments of 1 and indicates the next message buffer in the ABT area (for
details, refer to the process in Figure 19-47).
Caution
Be sure to abort ABT by clearing the ABTTRG bit to 0. The operation is not guaranteed if
aborting transmission is requested by clearing RDY.
When the normal operation mode with ABT is resumed after ABT has been aborted and the ABTTRG bit is set
to 1, the next ABT message buffer to be transmitted can be determined from the following table.
Status of TRQ of ABT Message Buffer
Abort After Successful Transmission
Abort After Erroneous Transmission
Set (1)
Next message buffer in the ABT area
Note
Same message buffer in the ABT area
Cleared (0)
Next message buffer in the ABT area
Note
Next message buffer in the ABT area
Note
The above resumption operation can be performed only if a message buffer ready for ABT exists in the
ABT area. For example, an abort request that is issued while ABT of message buffer 7 is in progress is
regarded as completion of ABT, rather than abort, if transmission of message buffer 7 has been
successfully completed, even if the ABTTRG bit is cleared to 0. If the C0MCTRLm.RDY bit in the next
message buffer in the ABT area is cleared to 0, the internal ABT pointer is retained, but the resumption
operation is not performed even if the ABTTRG bit is set to 1, and ABT ends immediately.
Remark
m = 00 to 31
19.10.5 Remote frame transmission
Remote frames can be transmitted only from transmit message buffers. Set whether a data frame or remote frame
is transmitted via the C0MCONFm.RTR bit. Setting (1) the RTR bit sets remote frame transmission.
Remark
m = 00 to 31