SPRAD59 October   2023 TMS320F280039

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
  5. 2 Key Differences Between DCAN and MCAN
  6. 3 Module Initialization
    1. 3.1 DCAN Initialization
    2. 3.2 MCAN Initialization
    3. 3.3 Initialization sequence
    4. 3.4 Code Snippets for Module Initialization
  7. 4 Bit Timing Configuration
  8. 5 Message RAM Configuration
  9. 6 Interrupt handling
    1. 6.1 MCAN Interrupt Sources
    2. 6.2 DCAN Interrupt Handling
    3. 6.3 MCAN Interrupt Handling
  10. 7 Transmitting data
    1. 7.1 Basic Transmission Process
      1. 7.1.1 Transmission with DCAN
      2. 7.1.2 Transmission with MCAN
    2. 7.2 MCAN Vs DCAN Transmit Procedural Differences
    3. 7.3 MCAN Transmit Concepts
      1. 7.3.1 Tx Event FIFO
  11. 8 Receiving Data
    1. 8.1 Introduction to Reception
    2. 8.2 Basic Reception Process
      1. 8.2.1 DCAN Reception
      2. 8.2.2 MCAN Reception
    3. 8.3 Filter Elements
      1. 8.3.1 Filter Element Structure
    4. 8.4 Rx Buffer
      1. 8.4.1 Receiving in Rx Buffer
    5. 8.5 Rx FIFO
      1. 8.5.1 Receiving in Rx FIFO
    6. 8.6 Receiving High Priority Messages
  12. 9 Avoiding network errors
  13. 10References

2 Key Differences Between DCAN and MCAN

CAN FD offers two significant advantages over classic CAN:

  • Faster bit-rate in the data-phase, increasing the overall throughput. An application can choose to transmit the entire frame at the same bit-rate by setting CCCR.BRSE = 0. This way, the application still takes advantage of the higher payload capability of CAN FD.
  • Higher payload size (up to 64 bytes) compared to classic CAN (up to 8 bytes), reducing protocol overhead.

Note that the physical-layer requirements in terms of transceiver, bus termination and so forth is identical between Classic CAN and CAN FD. If higher bit-rates are desired for the data phase in CAN FD, then transceivers designed for such bit-rates must be used.

Table 2-1 highlights the key differences between the DCAN and MCAN modules from a usage and programming perspective.

Table 2-1 DCAN and MCAN Feature Differences
Feature DCAN MCAN
Bit-rate Fixed bit-rate for the entire frame Two bit-rates can be used: a slower bit-rate for the nominal phase and a faster bit-rate for the data phase
Transmission speed Capped at 1Mbps Up to 1Mbps can be used for the nominal phase and up to 5Mbps for the data phase
Number of bytes transmitted per frame (Payload capability) Any number of bytes from 0 to 8 can be transmitted In addition to 0 to 8 bytes, transmission of 12/16/20/24/32/48/64 data bytes is possible
Nomenclature of data storage elements Data is stored in Message Objects. Message objects are also sometimes referred to as Mailboxes. Data is stored in buffers tied to filter elements
Number of data storage elements Fixed at 32, regardless of the number of bytes to be transmitted or received Depending on the configuration of the element, the number of buffers is flexible
CRC-field length 15 bits 15, 17 or 21-bit CRC
Time-stamping support No Yes
Transmitter delay compensation Not required Required for faster bit-rates in the data phase