Controller Area Network (FlexCAN)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
Freescale Semiconductor
25-15
Preliminary
25.3.4.2
Control Register (CANx_CTRL)
This register is defined for specific FlexCAN control features related to the CAN bus, such as bit-rate,
programmable sampling point within an Rx bit, loop back mode, listen only mode, bus off recovery
behavior and interrupt enabling (bus-off, error, warning). It also determines the division factor for the
clock prescaler. Most of the fields in this register should only be changed while the module is in disable
mode or in freeze mode. Exceptions are the BOFF_MSK, ERR_MSK, TWRN_MSK, RWRN_MSK and
BOFF_REC bits, that can be accessed at any time.
24–25
Reserved.
MAXMB
Maximum Number Of Message Buffers. This 6-bit field defines the maximum number of message buffers of
the FlexCAN module. The reset value (0x0F) is equivalent to a 16 MB configuration. This field should be
changed only while the module is in freeze mode.
Note: MAXMB has to be programmed with a value smaller or equal to the number of available message
buffers, otherwise FlexCAN will not transmit or receive frames.
Offset: Base + 0x0004
Access: User read/write
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R
PRESDIV
RJW
PSEG1
PSEG2
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
R BOFF
_MSK
ERR_
MSK
CLK_
SRC
LPB
TWRN
_ MSK
RWRN
_MSK
0
0
SMP
BOFF
_REC
TSY
N
LBUF LOM
PROPSEG
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 25-6. Control Register (CANx_CTRL)
Table 25-7. CANx_MCR Field Descriptions (continued)
Field
Description
Maximum MBs in use
MAXMB
1
+
=