upd70f3402 Renesas Electronics Corporation., upd70f3402 Datasheet - Page 641

• Manufacturer Part Number: upd70f3402
• Description: 32-/16-bit Single-chip Microcontroller With Can Interface
• Manufacturer: Renesas Electronics Corporation.

16.10.4 Transmission abort process
(1)
(2)
When the normal operation mode with ABT is resumed after ABT has been aborted and ABTTRG is set
to 1, the next ABT message buffer to be transmitted can be determined from the following table.
Note: The above resumption operation can be performed only if a message buffer ready for ABT
16.10.5 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 RTR bit of the CnMCONFm register. Setting (1) the RTR bit sets
remote frame transmission.
Set (1)
Cleared (0)
ABT Message Buffer
Transmission abort in normal operation mode
The user can clear the TRQ bit of the CnMCTRLm register 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 TSTAT bit of the CnCTRL register and
the CnTGPT register, which indicate the transmission status on the CAN bus (for details, refer to
the processing in Figure 16-66, “Transmission via Software Polling,” on page 669).
Transmission abort in normal operation mode with automatic block transmission (ABT)
To abort ABT that is already started, clear the ABTTRG bit of the CnGMABT register 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 fin-
ished. 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 16-67, “Transmission Abort Processing
(except Normal Operation Mode with ABT),” on page 670).
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 16-67).
Status of TRQ of
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 ABTTRG is cleared to 0. If the 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 ABTTRG is set to 1, and ABT
ends immediately.
Next message buffer in the ABT area
Next message buffer in the ABT area
User’s Manual U16702EE3V2UD00
Successful Transmission
Chapter 16 FCAN Controller
Abort After
Note
Note
Same message buffer in the ABT area
Next message buffer in the ABT area
Erroneous Transmission
Abort After
Note
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