Secondary results while Halting the Sub-CPU

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Secondary results while Halting the Sub-CPU

Post by Bitybity » Fri Aug 09, 2013 3:20 am

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.

Chilly Willy
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Post by Chilly Willy » Fri Aug 09, 2013 3:30 am

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.

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