be used primarily 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. Each FlexCAN module contains 64
message buffers.
The FlexCAN modules provide the following features:
• Based on and including all existing features of the Freescale TouCAN module
• 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
— Programmable bit rate up to 1 Mbit/s
• Content-related addressing
• 64 message buffers of zero to eight bytes data length
• Individual Rx Mask Register per message buffer
• Each message buffer configurable as Rx or Tx, all supporting standard and extended messages
• Includes 1088 bytes of embedded memory for message buffer storage
• Includes 256-byte memory for storing individual Rx mask registers
• Full featured Rx FIFO with storage capacity for six frames and internal pointer handling
• Powerful Rx FIFO ID filtering, capable of matching incoming IDs against 8 extended, 16 standard or 32 partial (8 bits)
IDs, with individual masking capability
• Selectable backwards compatibility with previous FlexCAN versions
• Programmable clock source to the CAN Protocol Interface, either system clock or oscillator clock
• Listen only mode capability
• Programmable loop-back mode supporting self-test operation
• 3 programmable Mask Registers
• Programmable transmit-first scheme: lowest ID, lowest buffer number or highest priority
• Time Stamp based on 16-bit free-running timer
• Global network time, synchronized by a specific message
• Maskable interrupts
• Warning interrupts when the Rx and Tx Error Counters reach 96
• Independent of the transmission medium (an external transceiver is assumed)
• Multi-master concept
• High immunity to EMI
• Short latency time due to an arbitration scheme for high-priority messages
• Low power mode, with programmable wake-up on bus activity
1.4.17 FlexRay
The MPC5644A includes one dual-channel FlexRay module that implements the FlexRay Communications System Protocol
Specification, Version 2.1 Rev A. Features include:
• Single channel support
• FlexRay bus data rates of 10 Mbit/s, 8 Mbit/s, 5 Mbit/s, and 2.5 Mbit/s supported
• 128 message buffers, each configurable as:
— Receive message buffer
— Single buffered transmit message buffer
— Double buffered transmit message buffer (combines two single buffered message buffer)
• 2 independent receive FIFOs
MPC5644A Microcontroller Data Sheet, Rev. 7
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Freescale Semiconductor