[Coco] COCO PSG - It's alive!
zippster278 at gmail.com
Sun Dec 25 10:38:53 EST 2016
For this test, when the CoCo boots, there is a small loader in the flash
in cart space at $C000 which copies the test program into motherboard RAM
to free up the banks (three right now). The song data is spread across 93 - 4K
banks in the 512K flash chip, which is where it’s playing from (through one area
of bank space at $C000-$CFFF).
So the flash gets some testing too. :)
Of course, you’d be able to use the SRAM for that purpose too, or play directly
from some other source, as long as it can keep up with the register updates
to the YM chip. If it can’t, that’s what the SRAM is there for.
> On Dec 25, 2016, at 5:42 AM, S Klammer <sklammer at gmail.com> wrote:
> Very nice!
> Once loaded by the Coco, is the CocoPSG playing the tunes from the 512K
> SRAM itself?
> Merry Christmas!
> On Dec 25, 2016 1:15 AM, "Zippster" <zippster278 at gmail.com> wrote:
>> It's alive!
>> Here's a video of the most recent board I've been working on getting some
>> initial testing.
>> This sound chip board, the COCO PSG, adds 1MB of combined FLASH and SRAM
>> as well
>> as a Yamaha YM2149 sound generator.
>> Test video
>> The board supports switching the sound generator frequency to either 1 or
>> 2MHz. The first tune,
>> Space Debris, is a CPC chiptune being played back with the 1MHz clock.
>> The second, Seagulls,
>> is (I think) from the ST scene and uses 2MHz.
>> These are both 50Hz register dumps.
>> There's quite a bit of chiptune music that can be easily converted for
>> playback on this for our CoCos,
>> and the possibility of making new tunes. I love this sound chip stuff,
>> lots of fun... :D
>> Merry Christmas everyone!!! :)
>> - Ed
>> Coco mailing list
>> Coco at maltedmedia.com
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