Chapter 22 FlexCAN
MPC5602P Microcontroller Reference Manual, Rev. 4
548
Freescale Semiconductor
22.3.4.2
Control Register (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.
22–23
IDAM
ID Acceptance Mode
This 2-bit field identifies the format of the elements of the Rx FIFO filter table, as shown in
. Note that all elements of the table are configured at the same time by this field (they
Section 22.3.3, “Rx FIFO structure.
26–31
MAXMB
Maximum Number of Message Buffers
This 6-bit field defines the maximum number of message buffers that will take part in the matching
and arbitration processes. The reset value (0x0F) is equivalent to 16 MB configuration. This field
should be changed only while the module is in Freeze Mode.
Maximum MBs in use = MAXMB + 1
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.
Table 22-12. IDAM coding
IDAM
Format
Explanation
00
A
One full ID (standard or extended) per filter element.
01
B
Two full standard IDs or two partial 14-bit extended IDs per filter element.
10
C
Four partial 8-bit IDs (standard or extended) per filter element.
11
D
All frames rejected.
Address: 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
TSYN LBUF LOM
PROPSEG
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 22-5. Control Register (CTRL)
Table 22-11. MCR field descriptions (continued)
Field
Description