DSTB1: I advise not to build any new ones for now
Posted: 27 Jun 2024 14:12
Bit of a public service announcement, copied from a reponse elsewhere:
I think I ought to warn people off building these for now.
I've spent a fair amount of time chasing my tail on the firmware for these and have reluctantly come to the conclusion the design's not reliable.
I think the first problem is trying to service DMA -- blitter, hard discs, floppies, etc. I should never have tried to do that as the firmware as originally written relied on the CPU and RAM clocks being related and they aren't when doing DMA.
So if you do use DSTB1, don't enable blitter is advice number one.
Also I don't think DSTB1 plays nicely with some hard disc emulators. My ACSI2STM seems to work OK, but my PicoHD is a non-starter. Be careful here.
However even taking those things into account there are some crashes I can't explain yet. I can pass memory tests all day, but then programs executing from AltRAM will randomly fail.
I have to reluctantly assume for now it's a design problem.
In short, if you have built one and it works for you, fantastic. But please don't use the blitter with it.
If you've not yet built one -- perhaps consider an alternative design or hold off for a rev 2*
Cheers,
BW
[*] That may be a fair hold, FWIW.