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TMS320F280039C-Q1: can registers

Jenney Ni
Intellectual 1730 points

Part Number: TMS320F280039C-Q1

Hi all,

The customer is experiencing software anomalies under high-temperature conditions. The CAN module's software logic is suspected. The following questions need to be checked:
1. In the customer's software logic, it is required to continuously wait for the Busy flag in the CAN_IFxCMD register to be cleared. Therefore, is there any operating condition under which the Busy bit in CAN_IF1CMD and CAN_IF2CMD registers remains set to 1 for more than 1ms?
2. Could external pin voltage levels, ambient temperature, or the operating condition of the CAN transceiver affect the Busy bit staying continuously set to 1? My understanding is that the Busy bit in CAN_IF1CMD and CAN_IF2CMD registers reflects an internal MCU data transfer status and is unrelated to external peripherals — is this correct?
3. Under what operating conditions would the Timer module's overflow flag fail to be set to 1? (The MCU crystal oscillator has been verified as normal, and PWM output is also normal.)
 
Regards,
Jenney
  1.  
  • +1
    TI__Mastermind 42930 points

    Hello Jenney,

    Jenney Ni said:
    . In the customer's software logic, it is required to continuously wait for the Busy flag in the CAN_IFxCMD register to be cleared. Therefore, is there any operating condition under which the Busy bit in CAN_IF1CMD and CAN_IF2CMD registers remains set to 1 for more than 1ms?

    Busy bit is set when there is an ongoing update on transfer between the IFxCMD registers and message RAM.  The last register update has probably not completed or may be stuck.

    Jenney Ni said:
    2. Could external pin voltage levels, ambient temperature, or the operating condition of the CAN transceiver affect the Busy bit staying continuously set to 1? My understanding is that the Busy bit in CAN_IF1CMD and CAN_IF2CMD registers reflects an internal MCU data transfer status and is unrelated to external peripherals — is this correct?

    Correct.  It should not be affected by any external pins or other peripherals.

    Jenney Ni said:
    . Under what operating conditions would the Timer module's overflow flag fail to be set to 1? (The MCU crystal oscillator has been verified as normal, and PWM output is also normal.)

    Not sure how timer is being associated with this issue.  Timer operates independently and its overflow flag would be set when timer counter threshold is reached.

    For this type of failure, it always helps to look at the CAN error and status registers as those might indicate the current status of the module.  Please ask customer to inspect the values for CAN_ES, CAN_ERRC, CAN_PERR and we can start from there.

    Regards,

    Joseph