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INA209: Programming GPIO

user6079270
Prodigy 40 points
Part Number: INA209

Hello,

I am new to circuit design and I am having trouble finding information on how to program the behaviour of the GPIO pin on the INA209.  All I need the device to do is to set the GPIO pin high once the input power reaches above a specified threshold and keep the pin high until the power drops below another threshold (Schmitt Trigger style).  The two power levels will be approximately an order of magnitude apart (~20 mW and ~600 mW) so resolution is not a major issue.  I was wondering if anyone could tell me the circuit connections needed to program the chip and the device needed to convert the code from USB into something the chip can use.

I would also like to know whether or not the chip's registers are volatile. 

Thank you,

CR

  • 0
    TI__Mastermind 27380 points

    Hi CR,

    The GPIO pin will not directly achieve what you described.

    You might use Critical pin instead. This pin is flexible with high/low programmable limits, and programmable hysteresis. It can be set to either latched or transparent. Therefore you may configure it to latch when over 600mW, and reset it when measured power dips below wherever you want it to be.

    You can read more about how to use Critical pin in the application section of the data sheet on page 17. Let us know if you have further questions.

    Regards, Guang

  • 0 in reply to Guang Zhou
    Prodigy 40 points

    Hello Guang,

    I've just read through the sections of the data sheet and I was wondering if the Warning or Over-Limit functions might be better as they use the calculated power value rather than just voltage which the critical pin seems to use?  The final power source will be a laser power converter which is provides neither a steady voltage nor current from my understanding.  In terms of programming would the device be configured each time the circuit is powered on using the I2C lines from the coordinating microcontroller to set the appropriate registers?

    Thanks,

    CR

  • 0 in reply to user6079270
    TI__Mastermind 27380 points

    Hi CR,

    Certainly, either over-limit or warning can be used for this purpose. Critical only works if bus voltage is constant.

    You’d have to reprogram each time the device powers up. Memory is volatile.

    Regards, Guang