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AMC7834EVM: How to reset after ADC overload shutdown?

Eric Peterson1
Prodigy 70 points
Part Number: AMC7834EVM

It seems that if there is an over voltage on either the ADC1-4 or SENSE1-4 inputs the ADC will set the registers to zero and indicate an alarm.  Once the over-voltage is corrected the alarm clears, but the ADC does not trigger again.  The only way I've found to overcome this is to cycle power to the EVM board. 

1) What is the correct way to recover from this situation?

2) What status bit should I monitor to determine if this over-voltage has happened?

Thanks,

Ric

  • 0
    TI__Guru 52663 points

    Hi Eric,

    I am not sure what you mean by "overvoltage".  Have you entered threshold limits in the ADC threshold registers? Which alarm values are being asserted and in which registers?

    Are you applying a large enough voltage to violate the abs max limit?

  • 0 in reply to Paul_Frost
    Prodigy 70 points

    Hi!

    In the case of the SENSE inputs, if the voltage happens to surpass 200mV it seems that the ADC will turn off and the register value for that input is set to zero. 

    The voltage being applied does not exceed the abs max limit as I'm only using a 5v supply.  In my test circuit I'm using a variable resistor to adjust the current flow through the SENSE resistor.  This may not exactly replicate the circuit that will be in our system, but it does indicate that there is a scenario that could cause this to happen.  I need to know how to sense this and how to recover.

    As far as the threshold limits, I haven't changed them from the defaults.  At the moment I don't have the system in front of me so can't say definitively which alarm values were being set.

    Thanks

    Ric

  • 0 in reply to Eric Peterson1
    TI__Guru 52663 points

    Moved this to the other thread.