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MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor
22-7
NOTE
Reading the control and status word (first word) of a message buffer locks
it from receiving further messages until it is unlocked by reading: another
message buffer, or the timer.
22.3.2
Message Buffer Structure
The message buffer structure used by the FlexCAN2 module is represented in
. Both extended
and standard frames (29-bit and 11-bit identifier, respectively) used in the CAN specification (version 2.0
Part B) are represented.
Table 22-3. Message Buffer MB0 Memory Mapping
Address
Offset
MB Field
0x80
Control and status (C/S)
0x84
Identifier field
0x88
–
0x8F
Data fields 0
–
7 (1 byte each)
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
0x0000
CODE
SRR
IDE
RT
R
LENGTH
TIME STAMP
0x0004
ID (Standard or Extended)
ID (Extended)
0x0008
Data byte 0
Data byte 1
Data byte 2
Data byte 3
0x000C
Data byte 4
Data byte 5
Data byte 6
Data byte 7
Figure 22-2. Message Buffer Structure
Table 22-4. Message Buffer Field Descriptions
Name
Description
CODE
Message buffer code. This 4-bit field can be accessed (read or write) by the CPU and by the
FlexCAN2 module itself, as part of the message buffer matching and arbitration process. The
encoding is shown in
. See
Section 22.4, “Functional Description
,” for
additional information.
SRR
Substitute remote request. Fixed recessive bit, used only in extended format. It must be set to ‘1’
by the user for transmission (TX Buffers) and is stored with the value received on the CAN bus for
RX receiving buffers. It can be received as either recessive or dominant. If FlexCAN2 receives this
bit as dominant, then it is interpreted as arbitration loss.
0 Dominant is not a valid value for transmission in extended format frames
1 Recessive value is compulsory for transmission in extended format frames
IDE
ID extended bit. This bit identifies whether the frame format is standard or extended.
0 Frame format is standard
1 Frame format is extended
Summary of Contents for MPC5566
Page 81: ...Introduction MPC5566 Microcontroller Reference Manual Rev 2 1 24 Freescale Semiconductor...
Page 135: ...Signal Description MPC5566 Microcontroller Reference Manual Rev 2 2 54 Freescale Semiconductor...
Page 189: ...Reset MPC5566 Microcontroller Reference Manual Rev 2 4 20 Freescale Semiconductor...
Page 603: ...Flash Memory MPC5566 Microcontroller Reference Manual Rev 2 13 38 Freescale Semiconductor...
Page 609: ...SRAM MPC5566 Microcontroller Reference Manual Rev 2 14 6 Freescale Semiconductor...
Page 1073: ...MPC5566 Microcontroller Reference Manual Rev 2 22 36 Freescale Semiconductor...
Page 1185: ...Nexus MPC5566 Microcontroller Reference Manual Rev 2 25 92 Freescale Semiconductor...