8-bit acorn hardware • Re: A potential way to detect the 1MHz clock phase

Is there anything you could deduce by triggering a light pen input and seeing which address it was accessing?

I tried that before last time I was looking at this, I don't think I managed to get anything out of it but that doesn't mean it's not possible... The latching there would sort of be the other way around, i.e. the CRTC is latching the timing of the light pen signal generated by the VIA, as opposed to the VIA latching the VSYNC signal from the CRTC. It does feel like it could work.

Statistics: Posted by gfoot — Mon Sep 22, 2025 12:08 am

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