Sorry I needed to edit this post since it didn't make sense the first time.
I've got a battery charging chip that says it has a pull down resistor internally on its Charge Enable (CE) pin to automatically enable charging of a battery. What if I don't want to enable charging first, can I put a stronger pull up resistor on this same pin to disable charging and then use a GPIO from a control board to enable charging by writing a LOW to the pin?
Which ONE?
That generally doesn't work: with an internal pull-down resistor AND an external pull-up, you are effectively creating a voltage divider and holding the pin mid state. At least, that is what it does on an MCU GPIO pin.
Since a logic low enables charging a logic high will disable charging. Just apply a logic high to your CE pin.
Ron
Yes I understand. Which that does work when I provide a logic HIGH from the MCU. I was just trying to keep it at disabled charging by putting a physical pull up resistor instead of relying on the MCU to turn on and then send a signal. I've just never done it while there was an internal pull down resistor on the same pin.
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