I came up with a new idea: during hardware development, it’s extremely convenient to have full control over all input and output pins.

Normally, this kind of control requires reflashing the firmware or reassigning functions in software—for example, mapping a button to a specific GPIO. If you’re using a debug probe, you can manipulate pins directly while the controller is running. However, I’m working in the Arduino IDE, so that approach isn’t practical.

My solution builds on the HTML interface I described earlier. I simply added a new page with toggle buttons to control the output pins and text indicators to display the logic input states. 

The result looks like this: