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TMS320F28062: will GPIO pin break when I configure it output high but accidentally short to GND?

Howard Zou
Genius 12365 points
Part Number: TMS320F28062

Hi,

I'm not sure if the GPIO pin break when I configure it output high but accidentally short to GND.

Or it's just that GPIO will be low in this state, but will resume when I disconnect it from GND.

  • 0
    TI__Mastermind 42195 points

    Howard,

    Howard Zou said:
    I'm not sure if the GPIO pin break when I configure it output high but accidentally short to GND.

    It is possible to have damaged the pin. Even if it still works you have shortened the expected lifetime of that pin.

    Howard Zou said:
    Or it's just that GPIO will be low in this state, but will resume when I disconnect it from GND.

    This is very common that the ground will pull the pin low while shorted. Afterwards it is quite common for the pin to still work as the output buffers are strong on this device. But it is possible for that pin to no longer work. This depends on the current and how long the buffer was exposed to that current.

    Regards,
    Cody 

  • 0 in reply to Cody Watkins
    TI__Genius 12365 points

    Hi, I ask this question because my customer has designed such schematic.

    C.RELAY is a GPIO. When it's configured high, 3.3V will be applied through GPIO to R96A, C13 to base of Q16A. There will be 10mA coming out of GPIO for no more than 600us(3*R96A* C13), when C13 is fully charged, the current coming out from GPIO will be (3.3V-0.7V)/(200ohm+499ohm)=3.7mA.

    So there will be pulse current of 10mA lasting less than 600us, and continuous current of 3.7mA coming out of GPIO. Is this acceptable for F28062?

  • 0 in reply to Howard Zou
    TI__Mastermind 42195 points

    Howard,

    10mA is above the value printed in the "Recommend operating conditions" table found in the Datasheet.

    When operating outside of the Recommended operating conditions we can not ensure other device parameters. This may work, however it is outside of our characterized operating conditions.

    Certain GPIO's have a higher current limit, you may be able to use one of those along with slightly different resistors values and guarantee that you will be with in the Recommended Operating Conditions.

    Regards,
    Cody 

  • 0 in reply to Cody Watkins
    TI__Genius 12365 points

    Hi,

    in absolute maximum rating we have clamp current up to 20mA, what does clamp current mean?

  • 0 in reply to Howard Zou
    TI__Mastermind 42195 points
    Howard,
    Clamp current is the device's ability to handle unexpected current caused by the Voltage being above VDDIO or below VSS without damaging the device.

    Regards,
    Cody