DocID018909 Rev 11
RM0090
Controller area network (bxCAN)
1112
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
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
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.