Controller area network (bxCAN)
RM0090
1092/1731
DocID018909 Rev 11
Bit 26
TME0
:
Transmit mailbox 0 empty
This bit is set by hardware when no transmit request is pending for mailbox 0.
Bits 25:24
CODE[1:0]
:
Mailbox code
In case at least one transmit mailbox is free, the code value is equal to the number of the
next transmit mailbox free.
In case all transmit mailboxes are pending, the code value is equal to the number of the
transmit mailbox with the lowest priority.
Bit 23
ABRQ2
:
Abort request for mailbox 2
Set by software to abort the transmission request for the corresponding mailbox.
Cleared by hardware when the mailbox becomes empty.
Setting this bit has no effect when the mailbox is not pending for transmission.
Bits 22:20 Reserved, must be kept at reset value.
Bit 19
TERR2
:
Transmission error of mailbox 2
This bit is set when the previous TX failed due to an error.
Bit 18
ALST2
:
Arbitration lost for mailbox 2
This bit is set when the previous TX failed due to an arbitration lost.
Bit 17
TXOK2
:
Transmission OK of mailbox 2
The hardware updates this bit after each transmission attempt.
0: The previous transmission failed
1: The previous transmission was successful
This bit is set by hardware when the transmission request on mailbox 2 has been completed
successfully. Please refer to
Bit 16
RQCP2
:
Request completed mailbox2
Set by hardware when the last request (transmit or abort) has been performed.
Cleared by software writing a “1” or by hardware on transmission request (TXRQ2 set in
CAN_TMID2R register).
Clearing this bit clears all the status bits (TXOK2, ALST2 and TERR2) for Mailbox 2.
Bit 15
ABRQ1
:
Abort request for mailbox 1
Set by software to abort the transmission request for the corresponding mailbox.
Cleared by hardware when the mailbox becomes empty.
Setting this bit has no effect when the mailbox is not pending for transmission.
Bits 14:12 Reserved, must be kept at reset value.
Bit 11
TERR1
:
Transmission error of mailbox1
This bit is set when the previous TX failed due to an error.
Bit 10
ALST1
:
Arbitration lost for mailbox1
This bit is set when the previous TX failed due to an arbitration lost.
Bit 9
TXOK1
:
Transmission OK of mailbox1
The hardware updates this bit after each transmission attempt.
0: The previous transmission failed
1: The previous transmission was successful
This bit is set by hardware when the transmission request on mailbox 1 has been completed
successfully. Please refer to
Bit 8
RQCP1
:
Request completed mailbox1
Set by hardware when the last request (transmit or abort) has been performed.
Cleared by software writing a “1” or by hardware on transmission request (TXRQ1 set in
CAN_TI1R register).
Clearing this bit clears all the status bits (TXOK1, ALST1 and TERR1) for Mailbox 1.