38 CAN FD - Controller Area Network, Flexible Data-Rate

This family of devices contain a Controller Area Network Flexible Data-Rate (CAN FD) module. CAN FD is a serial interface which is useful for communicating with other peripherals or microcontroller devices. This interface, or protocol, was designed to allow communications within noisy environments.

The CAN FD module is a communication controller, implementing the CAN FD protocol as defined in the BOSCH specification. This module supports CAN 1.2, CAN 2.0A, CAN 2.0B Passive, CAN 2.0B Active and CAN FD versions of the protocol. The module implementation is a full CAN FD system; however, the CAN specification is not covered within this data sheet. Refer to the BOSCH CAN specification for further details.

The CAN FD controller is capable of sending and receiving CAN 2.0 messages, and both CAN FD messages and CAN 2.0 messages can exist on the same bus. However, this does not mean that CAN FD and CAN 2.0 controllers need to be mixed on the same bus, as CAN 2.0 controllers will generate error frames upon receiving a CAN FD message.

Features of the CAN FD module include:

General

• Nominal (arbitration) bit rate up to 1 Mbps
• Data bit rate up to 8 Mbps (dependent on oscillator selection)
• CAN FD Controller modes:
  • Mixed CAN 2.0B and CAN FD mode
  • CAN 2.0B mode
• Conforms to ISO11898-1:2015

Message FIFOs

• Three FIFOs configurable as transmit or receive FIFOs
• One Transmit Queue (TXQ)
• Transmit Event FIFO (TEF) with 32-bit timestamp

Message Transmission

• Message transmission prioritization:
  • Based on priority bit field and/or
  • Message with lowest ID gets transmitted first using the TXQ
• Programmable automatic retransmission attempts: unlimited, three attempts or disabled

Message Reception

• 12 flexible filter and mask objects
• Each object can be configured to filter either:
  • Standard ID and first 18 data bits or
  • Extended ID
• 32-bit timestamp