Controller area network (bxCAN)
RM0090
1088/1731
DocID018909 Rev 11
–
Wakeup condition, SOF monitored on the CAN Rx signal.
–
Entry into Sleep mode.
32.9 CAN
registers
The peripheral registers have to be accessed by words (32 bits).
32.9.1 Register
access
protection
Erroneous access to certain configuration registers can cause the hardware to temporarily
disturb the whole CAN network. Therefore the CAN_BTR register can be modified by
software only while the CAN hardware is in initialization mode.
Although the transmission of incorrect data will not cause problems at the CAN network
level, it can severely disturb the application. A transmit mailbox can be only modified by
software while it is in empty state, refer to
Figure 340: Transmit mailbox states
The filter values can be modified either deactivating the associated filter banks or by setting
the FINIT bit. Moreover, the modification of the filter configuration (scale, mode and FIFO
assignment) in CAN_FMxR, CAN_FSxR and CAN_FFAR registers can only be done when
the filter initialization mode is set (FINIT=1) in the CAN_FMR register.
32.9.2
CAN control and status registers
Refer to
Section: List of abbreviations for registers
.
CAN master control register (CAN_MCR)
Address offset: 0x00
Reset value: 0x0001 0002
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
DBF
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET
Reserved
TTCM
ABOM
AWUM
NART
RFLM
TXFP
SLEEP
INRQ
rs
rw
rw
rw
rw
rw
rw
rw
rw
Bits 31:17 Reserved, must be kept at reset value.
Bit 16
DBF:
Debug freeze
0: CAN working during debug
1: CAN reception/transmission frozen during debug. Reception FIFOs can still be
accessed/controlled normally.
Bit 15
RESET:
bxCAN software master reset
0: Normal operation.
1: Force a master reset of the bxCAN -> Sleep mode activated after reset (FMP bits and
CAN_MCR register are initialized to the reset values). This bit is automatically reset to 0.
Bits 14:8 Reserved, must be kept at reset value.