I am working on a project that involves using an ATtiny85 to deliver a PWM signal to an RC filter. On the other side of the filter is an OP AMP that does not draw any current.
My question is: is it safe to allow a capacitor to discharge back into the ATtiny85 when the output signal is held low? How would I find the input impedance of the output pin when held low?
Is this recommended against? Any help is appreciated!
An image of the application (in a nutshell) is attached below: