GPIO Internal Pullup Resistor? Value of open input pin?

I am using Matrix HAL using C++ code. I have reviewed the various HAL C++ demos.

I desire to monitor a pin to see if it goes to ground (0V).

When a pin is set to input, what is its open value? Do I have to do an external pullup or pull down resistor?


Hi @sjmill01,

The GPIO pins go to the the FPGA and this one has pull ups when the pins are set as inputs. But you may want to use external pull up anyway to kind of protect the FPGA.

What board are you using, Creator or Voice?


I am using the Creator.

What value of resistor should I use to pull down a digital gpio pin. I’m getting about .300 V when I want to flag zero and my motor controller isn’t liking it.