SLAAET4 April   2025 MSPM0G3506 , MSPM0G3507 , MSPM0G3518 , MSPM0G3519

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 MCAN Features
  5. 2Sysconfig Configuration for MCAN Module
    1. 2.1 MCAN Clock Frequency
    2. 2.2 MCAN Basic Configuration
      1. 2.2.1 Transmitter Delay Compensation (TDC)
      2. 2.2.2 Bit Timing Parameters
      3. 2.2.3 Message RAM Configuration
        1. 2.2.3.1 Standard and Extended ID Filter Configuration
          1. 2.2.3.1.1 How to Add More Filters
        2. 2.2.3.2 TX MSG RAM
        3. 2.2.3.3 RX MSG RAM
    3. 2.3 Advanced Configuration
    4. 2.4 Retention Configuration
    5. 2.5 Interrupts
    6. 2.6 Pin Configuration and PinMux
  6. 3Demo Project Descriptions
    1. 3.1 TX Buffer Mode
    2. 3.2 TX FIFO Mode
    3. 3.3 RX Buffer Mode
    4. 3.4 RX FIFO Mode
  7. 4Debug and Design Tips to Resolve/Avoid CAN Communication Issues
    1. 4.1 Minimum Number of Nodes Required
    2. 4.2 Why a Transceiver is Needed
    3. 4.3 Bus Off Status
    4. 4.4 Using MCAN in Low Power Mode
    5. 4.5 Debug Checklist
      1. 4.5.1 Programming Issues
      2. 4.5.2 Physical Layer Issues
      3. 4.5.3 Hardware Debug Tips
  8. 5Summary
  9. 6References

3.2 TX FIFO Mode

The TX is configured as buffer mode in the current demo projects in SDK. The section below describes how to use TX in FIFO mode.

uint8_t MCAN_send_frame(uint32_t id, uint8_t* data, uint16_t len)
{
    frame_send_success = false;
    DL_MCAN_TxBufElement txMsg;
    DL_MCAN_TxFIFOStatus txfifoStatus;

    /* Initialize message to transmit. */
    /* Identifier Value. */
    txMsg.id = id;
    /* Transmit data frame. */
    txMsg.rtr = 0U;
    /* 11-bit standard identifier. */
    txMsg.xtd = 0U;
    /* ESI bit in CAN FD format depends only on error passive flag. */
    txMsg.esi = 0U;
    /* Transmitting 4 bytes. */
    txMsg.dlc = encode_dlc(len);
    /* CAN FD frames transmitted with bit rate switching. */
    txMsg.brs = protocol_mode;
    /* Frame transmitted in CAN FD format. */
    txMsg.fdf = protocol_mode;  //protocol_mode;
    /* Store Tx events. */
    txMsg.efc = 1U;
    /* Message Marker. */
    txMsg.mm = 0xAAU;
    /* Data bytes. */
    for (int i = 0; i < len; i++) txMsg.data[i] = data[i];
    while (DL_MCAN_OPERATION_MODE_NORMAL != DL_MCAN_getOpMode(CANFD0))
        ;

    /* Write Tx Message to the Message RAM (FIFO). */
    DL_MCAN_writeMsgRam(CANFD0, DL_MCAN_MEM_TYPE_FIFO, 0, &txMsg);

    /* Get put index and other TxFIFO details in txfifoStatus*/
    DL_MCAN_getTxFIFOQueStatus(CANFD0, &txfifoStatus);

    /* Enable Transmission interrupt.*/
    DL_MCAN_TXBufTransIntrEnable(CANFD0, txfifoStatus.putIdx, 1U);

    /* Add request for transmission. */
    DL_MCAN_TXBufAddReq(CANFD0, txfifoStatus.putIdx);
    if (txMsg.id == MCAN_HOST_ID) {
        while (frame_send_success == false) {
            ;
        }
    }
    return 0;
}

First, the TX message is saved in to Message RAM in FIFO type by calling DL_MCAN_writeMsgRam(). Then, get the index of this message, which indicates the location of the saved message in FIFO, by calling DL_MCAN_getTxFIFOQueStatus(). After, enable the transmission interrupt with the put index information of this message by calling DL_MCAN_TXBufTransIntrEnable(). Finally, call the add request for transmission with put index information of this message to transmit by calling DL_MCAN_TXBufAddReq().