
FlexCAN Module
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor
1391
32.2.1
Overview
The CAN protocol was primarily, but not only, designed to be used as a vehicle serial data bus, meeting
the specific requirements of this field: real-time processing, reliable operation in the EMI environment of
a vehicle, cost-effectiveness and required bandwidth. The FlexCAN module is a full implementation of the
CAN protocol specification, Version 2.0 B, which supports both standard and extended message frames.
A flexible number of Message Buffers (16, 32 or 64) is also supported. The Message Buffers are stored in
an embedded RAM dedicated to the FlexCAN module.
The CAN Protocol Interface (CPI) submodule manages the serial communication on the CAN bus,
requesting RAM access for receiving and transmitting message frames, validating received messages and
performing error handling. The Message Buffer Management (MBM) submodule handles Message Buffer
selection for reception and transmission, taking care of arbitration and ID matching algorithms. The Bus
Interface Unit (BIU) submodule controls the access to and from the internal interface bus, in order to
establish connection to the CPU and to other blocks. Clocks, address and data buses, interrupt outputs and
test signals are accessed through the Bus Interface Unit.
A typical CAN system is shown below in
. Each CAN station is connected physically to the
CAN bus through a transceiver. The transceiver provides the transmit drive, waveshaping, and
receive/compare functions required for communicating on the CAN bus. It can also provide protection
against damage to the FlexCAN caused by a defective CAN bus or defective stations.
Figure 32-2. Typical CAN system
32.2.2
FlexCAN module features
The FlexCAN module includes these distinctive features:
•
Full Implementation of the CAN protocol specification, Version 2.0B
— Standard data and remote frames
— Extended data and remote frames
— Zero to eight bytes data length
CANTX
CANRX
FlexCAN
Microcontroller
Tranceiver
CAN Station 1
CAN Station 2
CAN Station n
CAN Bus
Summary of Contents for MPC5644A
Page 2: ...MPC5644A Microcontroller Reference Manual Rev 6 2 Freescale Semiconductor...
Page 24: ...MPC5644A Microcontroller Reference Manual Rev 6 24 Freescale Semiconductor...
Page 26: ...MPC5644A Microcontroller Reference Manual Rev 6 26 Freescale Semiconductor...
Page 52: ...Introduction MPC5644A Microcontroller Reference Manual Rev 6 52 Freescale Semiconductor...
Page 56: ...Memory Map MPC5644A Microcontroller Reference Manual Rev 6 56 Freescale Semiconductor...
Page 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
Page 1440: ...FlexCAN Module MPC5644A Microcontroller Reference Manual Rev 6 1440 Freescale Semiconductor...