16.9.4 Transmission-Request-Reset Register (CANTRR)
These bits can only be set by the CPU and reset by the internal logic. These bits are reset when a transmission
is successful or is aborted. If the CPU tries to set a bit while the CAN tries to clear it, the bit is set.
Setting the TRR[
n
] bit of the message object
n
cancels a transmission request if it was initiated by the
corresponding bit (TRS[
n
]) and is not currently being processed. If the corresponding message is currently
being processed, the bit is reset when a transmission is successful (normal operation) or when an aborted
transmission due to a lost arbitration or an error condition is detected on the CAN bus line. When a transmission
is aborted, the corresponding status bit (AA.31-0) is set. When a transmission is successful, the status bit
(TA.31-0) is set. The status of the transmission request reset can be read from the TRS.31-0 bit.
The bits in CANTRR are set by writing a 1 from the CPU.
Figure 16-12. Transmission-Request-Reset Register (CANTRR)
31
0
TRR[31:0]
RS-0
LEGEND: RS = Read/Set; -
n
= value after reset
Table 16-11. Transmission-Request-Reset Register (CANTRR) Field Descriptions
Bit
Field
Value
Description
31:0
TRR[31:0]
Transmit-request-reset bits
1
Setting TRR
n
cancels a transmission request
0
No operation
16.9.5 Transmission-Acknowledge Register (CANTA)
If the message of mailbox
n
was sent successfully, the bit TA[
n
] is set. This also sets the GMIF0/GMIF1
(CANGIF0.15/CANGIF1.15) bit if the corresponding interrupt mask bit in the CANMIM register is set. The
GMIF0/GMIF1 bit initiates an interrupt.
The CPU resets the bits in CANTA by writing a 1. This also clears the interrupt if an interrupt has been
generated. Writing a 0 has no effect. If the CPU tries to reset the bit while the CAN tries to set it, the bit is set.
After power-up, all bits are cleared.
Figure 16-13. Transmission-Acknowledge Register (CANTA)
31
0
TA[31:0]
RC-0
LEGEND: RC = Read/Clear; -
n
= value after reset
Table 16-12. Transmission-Acknowledge Register (CANTA) Field Descriptions
Bit
Field
Value
Description
31:0
TA[31:0]
Transmit-acknowledge bits
1
If the message of mailbox
n
is sent successfully, the bit
n
of this register is set.
0
The message is not sent.
Controller Area Network (CAN)
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
TMS320x2806x Microcontrollers
1027
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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