dsPIC33/PIC24 Family Reference Manual
DS70005340A-page 2 2018 Microchip Technology Inc.
1.0 INTRODUCTION
CAN Flexible Data-Rate (FD) addresses the increasing demand for bandwidth on CAN buses.
The two major enhancements over CAN 2.0B consist of:
• Increased data field up to 64 data bytes (currently 8 bytes)
• Option to switch to faster bit rate after the arbitration field
Figure 1-1 shows the possible increase in net bit rate due to the higher Data Bit Rate (DBR) and
increased data bytes per frame (© Robert Bosch GmbH).
Figure 1-1: Net CAN FD Bit Rate
The CAN FD protocol is defined to allow CAN 2.0 messages and CAN FD messages to co-exist
on the same bus. This does not imply that non-CAN FD controllers can be mixed with CAN FD
controllers on the same bus. Non-CAN FD controllers will generate error frames while receiving
a CAN FD message.
1.1 Features
The CAN FD module has the following features:
General
• Nominal (Arbitration) Bit Rate up to 1 Mbps
• Data Bit Rate up to 8 Mbps
• CAN FD Controller modes:
- Mixed CAN 2.0B and CAN FD mode
- CAN 2.0B mode
• Conforms to ISO11898-1:2015
Message FIFOs
• 31 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, 3 Attempts or Disabled
Frame ID: 11-Bit, Bit Rate Arbitration: 1 Mbit
To Next Page
Loading...
Need help?
General
