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

4.4 Using MCAN in Low Power Mode

Users need to put the MCU in low power mode to meet the application requirements. However, the MCAN module is disabled in low power mode. As a workaround, users can configure the MCAN RX pin as an input pin before entering low power mode. Enable a edge fail interrupt on that pin. When there is one message received on the MCAN RX pin, the MCU is woken up by the edge fail interrupt. Then, reconfigure the MCAN RX pin as an MCAN function and reconfigure the MCAN module. The MCAN restores normal functions this way.

Note: The first MCAN message is used as a wake up signal for the MCU. Use a test message for this wake up function.

An example code is shown below.

void MCAN_LowPowerMode(void)
{
    DL_GPIO_initDigitalInputFeatures(GPIO_MCAN0_IOMUX_CAN_RX,
         DL_GPIO_INVERSION_DISABLE, DL_GPIO_RESISTOR_PULL_UP,
         DL_GPIO_HYSTERESIS_DISABLE, DL_GPIO_WAKEUP_DISABLE);
    DL_GPIO_setLowerPinsPolarity(GPIO_MCAN0_CAN_RX_PORT, DL_GPIO_PIN_13_EDGE_FALL);
    DL_GPIO_clearInterruptStatus(GPIO_MCAN0_CAN_RX_PORT, GPIO_MCAN0_CAN_RX_PIN);
    DL_GPIO_enableInterrupt(GPIO_MCAN0_CAN_RX_PORT, GPIO_MCAN0_CAN_RX_PIN);

    DL_SYSCTL_setPowerPolicySTANDBY0();
    __WFI();
    DL_SYSCTL_setPowerPolicyRUN0SLEEP0();

    DL_GPIO_initPeripheralInputFunction(
        GPIO_MCAN0_IOMUX_CAN_RX, GPIO_MCAN0_IOMUX_CAN_RX_FUNC);

    MCAN0_Restart();
}
/*MCAN restart function*/
void MCAN0_Restart(void)
{
    DL_MCAN_reset(CANFD0);
    delay_cycles(16);
    DL_MCAN_disablePower(CANFD0);
    delay_cycles(32);
    DL_MCAN_enablePower(CANFD0);
    // MCAN RAM need at least 50us to finish init
    // 1600 CPU cycles@CPU32MHz
    // 4000 CPU cycles@CPU80MHz
    delay_cycles(4000);
    SYSCFG_DL_MCAN0_init();
}