Datasheet

V850ES/JG3-H, V850ES/JH3-H CHAPTER 20 CAN CONTROLLER
R01UH0042EJ0500 Rev.5.00 Page 996 of 1513
Aug 12, 2011
20.10.4 Transmission abort process
Remark m = 00 to 31
(1) Transmission abort process other than in normal operation mode with automatic block transmission (ABT)
The user can clear the C0MCTRLm.TRQ bit to 0 to abort a transmission request. The TRQ bit will be cleared
immediately if the abort was successful. Whether the transmission was successfully aborted or not can be
checked using the C0CTRL.TSTAT bit and the C0TGPT register, which indicate the transmission status on the
CAN bus (for details, refer to the processing in Figure 20-46).
(2) Transmission abort process except for ABT transmission in normal operation mode with automatic block
transmission (ABT)
The user can clear the C0GMABT.ABTTRG bit to 0 to abort a transmission request. After checking the ABTTRG
bit of the C0GMABT register = 0, clear the C0MCTRLm.TRQ bit to 0. The TRQ bit will be cleared immediately if the
abort was successful. Whether the transmission was successfully aborted or not can be checked by using the
C0CTRL.TSTAT bit and the C0TGPT register, which indicate the transmission status on the CAN bus (for details,
refer to the process in Figure 20-47).
(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 20-48 (a)). 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 20-48 (b)).
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
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