This is a water pump in a cooling loop. The input signal is a PWM input and output(fg) is a time based output. I have attached the signal descriptions and images from the manufacturer.
I can't understand how to read the output while giving the input?
If you look at the red arrows, you see the controller has an input and an output.
The input will read the PWM signal, and the output will turn the current sink on and off.
to read the output determine if there is significant current (600mv/39R is about 15mA) flowing into the pin during PWM high.
something like this perhaps.
Or like this if you want the FG signal to stay high durinng PWM lows.
simulate this circuit – Schematic created using CircuitLab
That's an open collector IO pin. It can read the wire but also pull and keep it low.
You can put a similar circuit to your MCU where MCU output drives the PWM and another MCU pin reads the same wire back.
