Goos_E Posted May 15, 2015 Report Share Posted May 15, 2015 Jack, I tried the card I use for the acorn atom also for the atari 800 and it works just fine. I can load *.car and *.atr. So I think it is not my card that is the fault. I tried a Philips a Kingston and a sandisk card with my acorn atom. All the cards give a N/A sign in *HELP and *CAT.I am monday free so I can get some measerements with my osciloscoop. You will here from me. Goos. Quote Link to comment Share on other sites More sharing options...
foft Posted May 15, 2015 Report Share Posted May 15, 2015 In Atari 800 I use code from this site, which I think follows the linked process below (I've not checked). It seems pretty robust.http://elm-chan.org/docs/mmc/gx1/sdinit.png Quote Link to comment Share on other sites More sharing options...
hoglet Posted May 15, 2015 Author Report Share Posted May 15, 2015 Foft, Thanks for that info - very useful. What's really weird in this case is it's failing very early on - at the CMD0 - and up to this point I can't see any difference between your flow chart, and what the Atom code is doing. Can I ask what kind of speed the SD Clock would be running at in the Atari? Dave Quote Link to comment Share on other sites More sharing options...
foft Posted May 15, 2015 Report Share Posted May 15, 2015 I use this spi master hardware:https://www.eewiki.net/display/LOGIC/Serial+Peripheral+Interface+%28SPI%29+Master+%28VHDL%2956Mhz clk, clk_div is set to 2. So I think about 14MHz but To be honest I never double checked with my scope or la!Edit: of course init runs slow before the speed is boosted. I use a divider of 128 for that.Oh and worth checking the code matches the flow chart:) http://www.scrameta.net/atarixlfpga_svn/trunk/atari_800xl/firmware/sd_direct/ Quote Link to comment Share on other sites More sharing options...
hoglet Posted May 16, 2015 Author Report Share Posted May 16, 2015 Foft, Thanks for those links. Turns out we are both using the same code (even the comments are identical). I'll do some diffs later, to see if there are any subtle variations. This just isn't making sense.... Dave Quote Link to comment Share on other sites More sharing options...
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