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Secondary results while Halting the Sub-CPU

Posted: Fri Aug 09, 2013 3:20 am
by Bitybity
Hello everyone.

I have been experimenting accessing the PRG-RAM from Main-CPU; done by sending a BUSREQ to the Sub (So it halts).

I tried putting an infinite loop in PRG-RAM for Main-CPU, just for testing purposes.
While the Sub keeps in BUSREQ status, I noticed the "activity" led from Gens keeps turned on.

So, my question is, though I hadn't any important bugs so far, while Sub is halted, does the CDDA, in hardware, stop playing or something?

Thanks for your answers.

Posted: Fri Aug 09, 2013 3:30 am
by Chilly Willy
You have to keep the CPU running AND generate INT2 periodically for the CD to keep working. I'm not sure if you can halt the 68000 and INT2s, then start it again later and have it work right. That may be fine - I've just never tried it.