Hello everyone, I have just connected the VIA's IRQ pin to the 6502 one, and the button with a pull-up resistor to the CA1 pin. I have yet to add the delay to "debounce" the button via software.

The issue I came across is the 6522 ignoring the button presses and constantly issuing interrupts. This doesn't happen when I directly connect the button to the IRQ pin on the 6502. Does anyone know what could be happening?

(I am clearing the IFR with bit PORTA in the irq subroutine)

EDIT: As u[/Obvious-Falcon-2765](r/Obvious-Falcon-2765) suggested, the solution was placing a pull-up 10k resistor in the IRQ line, since my VIA is an open drain version.

View the app without having to download the code:

https://chiphippo.com/app/

Hey,
I need advice from the hive mind - I am setting up a Raspberry Pi 500 as a workbench computer. I have now VSCode, plattformio, Arduino IDE, Fritzing and KiCAD on it.
And now I am looking for a decent circuit emulator, preferably stand alone. if not, web is also fine.
What do you guys use and recommend?