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TMS320F280039C: Application issues of chips

Tonyx.wu
Genius 4445 points

Part Number: TMS320F280039C

When we were using input pin GPIO49, we externally connected it to 3.3K through a pull-up resistor of 4.7K and found that the voltage of this pin was 1.2V. This situation is very strange. Could you help us find the reason? Thank you!

  • 0
    Genius 4445 points

    Is there an update on the situation? It's a bit urgent, thank you!

  • 0
    TI__Expert 6020 points

    Hi Tony,

    As per my understanding in your use-case GPIO49 is used as EPWM (MCU_LLC1_PWM_NFLTB) but the GPIO49 is not muxed to EPWM peripheral. If not which mux option you are using at GPIO49?

    instead of 3.3V level you are observing 1.2V level is that correct? This is strange, let me check internally with experts. 

    Please provide additional info.

    1. The scope shots for GPIO49 & GPIO52

    2. Confirm if your power rails are as expected?

    Thanks & Regards,

    Uttam

  • 0 in reply to Uttam Reddy Pailla
    Genius 4445 points

    The information you requested is as above. Could you please help us quickly identify what the problem is and how it can be resolved? Thank you!

    I am in a hurry to solve these problems

  • 0 in reply to Tonyx.wu
    TI__Mastermind 19795 points

    Hi Tony,

    Tonyx.wu said:
    connected it to 3.3K through a pull-up resistor of 4.7K

    Did you mean 3.3V? Is the "K" a typo? That is what Uttam was asking.

      

    1. Please provide a circuit diagram of the resistors you are connecting to the pin, and all voltage rails that are connected to that pin.

    2. Seeing a voltage of 1.2V is not possible unless the external circuitry you are using is driving it to 1.2V. This is likely an external circuit issue. To test this:

    Please disconnect the pin from the rest of the circuit and read the voltage at the pin.

    3. The only other possibility is if you have damaged the pin by over-voltage (applying greater than absolute maximum ratings to the pin). Have you ever accidentally applied 5V to the pin?

    Regards,

    Vince