37.8.46 Tx Buffer Request Pending

Note: The TXBRP bits which are set while a Tx scan is in progress are not considered during this particular Tx scan. In case a cancellation is requested for such a Tx Buffer, this Add Request is canceled immediately, the corresponding TXBRP bit is reset.

Table 37-54. Register Bit Attribute Legend
Symbol	Description	Symbol	Description	Symbol	Description
R	Readable bit	HC	Cleared by Hardware	(Grey cell)	Unimplemented
W	Writable bit	HS	Set by Hardware	X	Bit is unknown at Reset
K	Write to clear	S	Software settable bit	—	—

Name:	TXBRP
Offset:	0x1CC
Reset:	0x00000000
Property:	R


Bit	31	30	29	28	27	26	25	24
	TRP31	TRP30	TRP29	TRP28	TRP27	TRP26	TRP25	TRP24
Access	R	R	R	R	R	R	R	R
Reset	0	0	0	0	0	0	0	0


Bit	23	22	21	20	19	18	17	16
	TRP23	TRP22	TRP21	TRP20	TRP19	TRP18	TRP17	TRP16
Access	R	R	R	R	R	R	R	R
Reset	0	0	0	0	0	0	0	0


Bit	15	14	13	12	11	10	9	8
	TRP15	TRP14	TRP13	TRP12	TRP11	TRP10	TRP9	TRP8
Access	R	R	R	R	R	R	R	R
Reset	0	0	0	0	0	0	0	0


Bit	7	6	5	4	3	2	1	0
	TRP7	TRP6	TRP5	TRP4	TRP3	TRP2	TRP1	TRP0
Access	R	R	R	R	R	R	R	R
Reset	0	0	0	0	0	0	0	0

Bits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 – TRPn Transmission Request Pending

Each Tx Buffer has its own Transmission Request Pending bit.

The bits are reset after a requested transmission has completed or has been cancelled via register TXBCR.

TXBRP bits are set only for those Tx Buffers configured via TXBC. After a TXBRP bit has been set, a Tx scan is started to check for the pending Tx request with the highest priority (Tx Buffer with lowest Message ID).

A cancellation request resets the corresponding transmission request pending bit of register TXBRP. In case a transmission has already been started when a cancellation is requested, this is done at the end of the transmission, regardless whether the transmission was successful or not. The cancellation request bits are reset directly after the corresponding TXBRP bit has been reset.

After a cancellation has been requested, a finished cancellation is signaled via TXBCF

after successful transmission together with the corresponding TXBTO bit
when the transmission has not yet been started at the point of cancellation
when the transmission has been aborted due to lost arbitration
when an error occurred during frame transmission

In DAR mode all transmissions are automatically canceled if they are not successful. The corresponding TXBCF bit is set for all unsuccessful transmissions.

Value	Description
0	No transmission request pending.
1	Transmission request pending.