dmb@wam.umd.edu (David M. Baggett) (10/11/90)
Many people have sent hints on playing sound through the STe's DMA sound mechanism. (Thanks everyone!) One problem that has been pointed out to me is that only four playback rates are available: 50kHz, 25kHz, 12.5kHz, and 6.25kHz. Since these are nonstandard rates (with respect to CD's and DAT's at least), the DMA sound mechanism alone seems severely handicapped. I have never found any samples that were recorded at these rates, and although it would be straightforward (but nontrivial) to convert exisiting samples to these rates, this sure seems like a lot of trouble to go to when we've already got 100's of megs of 11kHz and 8kHz samples floating around. Question: Does anyone know if it's possible to use the STe DAC chip directly? In other words, is there a way I can just bypass the DMA stuff and use MFP Timer A to control sample playing (as with normal ST's)? It would be nice to have 8 bits of resolution instead of 5; the sound quality should be superior using the STe DAC than using the cheezy sound chip in standard ST's. (The Hippo digitizer is one I already support, and it sounds quite a bit better than the ST's PSG chip.) I relize that using Timer A will eat up the CPU, but I see no way around it. Could someone at Atari please comment on this? The documentation I have on the STe's sound is vauge when it comes to poking the DAC directly. Is there a register I can just stuff samples into? (I.e., Can I just update the volume register(s) directly without turning on the DMA?) Thanks in advance. Dave Baggett dmb%wam.umd.edu@uunet.uu.net