SNDh2AYc - iNViTRO for Benediction Coding Party

[Targhan]

Yes, the DMA allows you to buffer AY values, so that you the player can fill it, and then is done, and you have all the rest of the CPU to do your game/effect. This is also what allows Grim (in the Semilanceata demos: Sappy and Seminoisin), and also Power (Heat Beats demo), featuring samples and MOD playing, to mix effects with more elaborate sounds.

Doing that on a real CPC is from ultra-bothersome to impossible, depending on what you want to achieve.

[andycadley]

The DMA has 3 channels that each run a sort of mini program, without the CPU needing to be involved. Each can execute one  command per scanlines, so you can effectively write to 3 AY registers every 64us.

The advantage is twofold: 1) It can do this without the CPU being involved and the timing can be very precise. 2) Three arbitrary register writes is faster than the CPU can ever do, so you can feed the AY more data.