ST STM32F405

Controller area network (bxCAN) RM0090
1108/1749 RM0090 Rev 18
CAN TX mailbox identifier register (CAN_TIxR) (x=0..2)
Address offsets: 0x180, 0x190, 0x1A0
Reset value: 0xXXXX XXXX (except bit 0, TXRQ = 0)
All TX registers are write protected when the mailbox is pending transmission (TMEx reset).
This register also implements the TX request control (bit 0) - reset value 0.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
STID[10:0]/EXID[28:18] EXID[17:13]
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
1514131211109876543210
EXID[12:0] IDE RTR TXRQ
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
Bits 31:21 STID[10:0]/EXID[28:18]: Standard identifier or extended identifier
The standard identifier or the MSBs of the extended identifier (depending on the IDE bit
value).
Bits 20:3 EXID[17:0]: Extended identifier
The LSBs of the extended identifier.
Bit 2 IDE
: Identifier extension
This bit defines the identifier type of message in the mailbox.
0: Standard identifier.
1: Extended identifier.
Bit 1 RTR
: Remote transmission request
0: Data frame
1: Remote frame
Bit 0 TXRQ
: Transmit mailbox request
Set by software to request the transmission for the corresponding mailbox.
Cleared by hardware when the mailbox becomes empty.