Chapter 25 flexcan, 1 features, Chapter 25 – Motorola ColdFire MCF5281 User Manual
Page 471: Flexcan, 1 features -1
Freescale Semiconductor
25-1
Chapter 25
FlexCAN
The FlexCAN module is a communication controller implementing the controller area network (CAN)
protocol, an asynchronous communications protocol used in automotive and industrial control systems. It
is a high speed (1 Mbit/sec), short distance, priority based protocol which can communicate using a variety
of mediums (for example, fiber optic cable or an unshielded twisted pair of wires). The FlexCAN supports
both the standard and extended identifier (ID) message formats specified in the CAN protocol
specification, revision 2.0, part B.
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. A general working knowledge of the CAN protocol
revision 2.0 is assumed in this document. For details, refer to the CAN protocol revision 2.0 specification.
25.1
Features
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Based on and includes all existing Freescale TouCAN module features
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Freescale IP interface architecture
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Full implementation of the CAN protocol specification version 2.0
— Standard data and remote frames (up to 109 bits long)
— Extended data and remote frames (up to 127 bits long)
— 0–8 bytes data length
— Programmable bit rate up to 1Mbit/sec
•
Up to 16 flexible message buffers of 0–8 bytes data length, each configurable as Rx or Tx, all
supporting standard and extended messages
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Listen-only mode capability
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Content-related addressing
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No read/write semaphores
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Three programmable mask registers: global (for MBs 0-13), special for MB14, and special for
MB15
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Programmable transmit-first scheme: lowest ID or lowest buffer number
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“Time Stamp”, based on 16-bit free-running timer
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Global network time, synchronized by a specific message
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Programmable I/O modes
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Maskable interrupts
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Independent of the transmission medium (external transceiver is assumed)
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Open network architecture
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Multimaster bus
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High immunity to EMI
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Short latency time for high-priority messages
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Low-power “sleep” mode, with programmable “wake up” on bus activity
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3