
FlexCAN Module
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor
1421
Figure 32-17. Rx Individual Mask Registers (RXIMR0 – RXIMR63)
32.5
Functional description
32.5.1
Overview
The FlexCAN module is a CAN protocol engine with a very flexible mailbox system for transmitting and
receiving CAN frames. The mailbox system is composed by a set of up to 64 Message Buffers (MB) that
store configuration and control data, time stamp, message ID and data (see
Section 32.4.3, Message buffer
). The memory corresponding to the first eight message buffers can be configured to support a
FIFO reception scheme with a powerful ID filtering mechanism, capable of checking incoming frames
against a table of IDs (up to eight extended IDs or sixteen standard IDs or thirty-two 8-bit ID slices), each
one with its own individual mask register. Simultaneous reception through FIFO and mailbox is supported.
For mailbox reception, a matching algorithm makes it possible to store received frames only into message
buffers that have the same ID programmed on its ID field. A masking scheme makes it possible to match
the ID programmed on the message buffer with a range of IDs on received CAN frames. For transmission,
an arbitration algorithm decides the prioritization of message buffers to be transmitted based on the
message ID (optionally augmented by three local priority bits) or the message buffer ordering.
Before proceeding with the functional description, an important concept must be explained. A Message
Buffer is said to be “active” at a given time if it can participate in the matching and arbitration algorithms
that are happening at that time. An Rx message buffer with a ‘0000’ code is inactive (refer to
Similarly, a Tx message buffer with a ‘1000’ or ‘1001’ code is also inactive (refer to
message buffer not programmed with ‘0000’, ‘1000’ or ‘1001’ will be temporarily deactivated (will not
participate in the current arbitration or matching run) when the CPU writes to the C/S field of that message
buffer (see
Section 32.5.6.2, Message buffer deactivation
).
Base + 0x0880–0x097F
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
MI31 MI30 MI29 MI28 MI27 MI26 MI25 MI24 MI23 MI22 MI21 MI20 MI19 MI18 MI17 MI16
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
MI15 MI14 MI13 MI12 MI11 MI10
MI9
MI8
MI7
MI6
MI5
MI4
MI3
MI2
MI1
MI0
Table 32-17. RXIMR0 – RXIMR63 Register field descriptions
Field
Description
MI31–MI0
Mask Bits
For normal Rx message buffers, the mask bits affect the ID filter programmed on the message
buffer. For the Rx FIFO, the mask bits affect all bits programmed in the filter table (ID, IDE, RTR).
1: The corresponding bit in the filter is checked against the one received
0: the corresponding bit in the filter is “don’t care”
Содержание MPC5644A
Страница 2: ...MPC5644A Microcontroller Reference Manual Rev 6 2 Freescale Semiconductor...
Страница 24: ...MPC5644A Microcontroller Reference Manual Rev 6 24 Freescale Semiconductor...
Страница 26: ...MPC5644A Microcontroller Reference Manual Rev 6 26 Freescale Semiconductor...
Страница 52: ...Introduction MPC5644A Microcontroller Reference Manual Rev 6 52 Freescale Semiconductor...
Страница 56: ...Memory Map MPC5644A Microcontroller Reference Manual Rev 6 56 Freescale Semiconductor...
Страница 130: ...Device Performance Optimization MPC5644A Microcontroller Reference Manual Rev 6 130 Freescale Semiconductor...
Страница 204: ...Multi Layer AHB Crossbar Switch XBAR MPC5644A Microcontroller Reference Manual Rev 6 204 Freescale Semiconductor...
Страница 212: ...Peripheral Bridge PBRIDGE MPC5644A Microcontroller Reference Manual Rev 6 212 Freescale Semiconductor...
Страница 558: ...System Integration Unit SIU MPC5644A Microcontroller Reference Manual Rev 6 558 Freescale Semiconductor...
Страница 582: ...Frequency modulated phase locked loop FMPLL MPC5644A Microcontroller Reference Manual Rev 6 582 Freescale Semiconductor...
Страница 766: ...Enhanced Time Processing Unit eTPU2 MPC5644A Microcontroller Reference Manual Rev 6 766 Freescale Semiconductor...
Страница 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
Страница 1236: ...System Information Module and Trim SIM MPC5644A Microcontroller Reference Manual Rev 6 1236 Freescale Semiconductor...
Страница 1250: ...Cyclic Redundancy Checker CRC Unit MPC5644A Microcontroller Reference Manual Rev 6 1250 Freescale Semiconductor...
Страница 1336: ...Deserial Serial Peripheral Interface DSPI MPC5644A Microcontroller Reference Manual Rev 6 1336 Freescale Semiconductor...
Страница 1388: ...Enhanced Serial Communication Interface ESCI MPC5644A Microcontroller Reference Manual Rev 6 1388 Freescale Semiconductor...
Страница 1440: ...FlexCAN Module MPC5644A Microcontroller Reference Manual Rev 6 1440 Freescale Semiconductor...
Страница 1624: ...FlexRay Communication Controller FlexRay MPC5644A Microcontroller Reference Manual Rev 6 1624 Freescale Semiconductor...
Страница 1670: ...JTAG Controller JTAGC MPC5644A Microcontroller Reference Manual Rev 6 1670 Freescale Semiconductor...
Страница 1692: ...Nexus Port Controller NPC MPC5644A Microcontroller Reference Manual Rev 6 1692 Freescale Semiconductor...
Страница 1701: ...Development Trigger Semaphore DTS MPC5644A Microcontroller Reference Manual Rev 6 Freescale Semiconductor 1701...
Страница 1702: ...Development Trigger Semaphore DTS MPC5644A Microcontroller Reference Manual Rev 6 1702 Freescale Semiconductor...