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The Prologica CP-400 (CoCo Clone) uses the PAL-M TV system. My question to the hardware experts is - If you were to run a program on the CP-400 that detects the difference between PAL and NTSC by counting interrupts (Like MDetect ), would it be (incorrectly) detected as NTSC or PAL?

Since the fs and hs interrupts are generated by the vdg, I would say that yes it would detect as NTSC.

Though the same is true for the dragon, it's other circuitry cheats and stops the vdg clock for 50 odd scanlines each half frame, so generating a 50Hz fs.

Though for timing purposes PAL-M being detected as NTSC, shouldn't matter as they are both 60Hz.

Cheers,

Phill.

Thanks Phill!

Regards,
Steve