So I was still getting glitches on my inputs for Reset_Vector. I couldn’t figure out what was causing it because it would happen randomly and I couldn’t repeat the problem. The false inputs caused issues with ball triggering, score detection, and playfield actions. I figured it had to be glitches on the lines caused by EMF or something on the input driver. I knew it was the input driver cause when a solenoid fired randomly like the pop bumper it would register a hit which means that the microcontroller detected a hit.

To fix this issue I added a simple debouncer routine. Basically it makes sure a input is pressed for at least 2 Kernel cycles before saying that it was a hit. This keeps random spikes from registering as hits.

What it does is read in the inputs into a variable called new_inputs. The new_inputs then gets anded with a variable called old_inputs and the result is the inputs that where held for two kernel cycles. Then the new_inputs is copied into old_inputs for the next cycle to happen.

This system can be easily expanded to 3,4,ect cycles so the debouncer is extremely configurable in its sensitivity.