In the Christmas break I’ve finally found a little bit of time to tinker with FPGAs again.\u00a0 Not enough to tackle anything major, but I’ve done a little bit of bug fixing on the OneChipMSX core.<\/p>\n
Or so I thought.<\/p>\n
A problem with the OneChipMSX core on newer MIST boards was brought to my attention, and when it became clear that the affected boards all had a different revision of SDRAM chip that’s where I started looking.\u00a0 I thought I had timing constraints for the SDRAM in place, but it turns out that wasn’t the case, so having added constraints I built the core, sent it to a tester who had both a new and old revision board, and was told all was well.<\/p>\n
I’ve since had a report that the new version has problems with disk errors once MSX DOS is booted, and while I can’t reproduce that problem with the released revision of the core, I’ve since made some changes to reset handling so that it’s finally possible to hard-reset the core and clear a loaded ROM without power-cycling – and now I can’t build a core for the MIST that doesn’t give MSX DOS errors!<\/p>\n
Building for DE2 results in a core that works just fine.\u00a0 Building for DE1 results in a core that hangs on loading the BIOS – which is exactly the symptom the newer revision MIST boards were showing – but I don’t have any block RAM left so I can’t use SignalTap to diagnose it!<\/p>\n
So clearly I’m getting rusty!\u00a0 I’m hoping I’ll find time before going back to work to figure out what’s going on!<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Christmas break I’ve finally found a little bit of time to tinker with FPGAs again.\u00a0 Not enough to tackle anything major, but I’ve done a little bit of bug fixing on the OneChipMSX core. Or so I thought.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-1138","post","type-post","status-publish","format-standard","hentry","category-fpga"],"_links":{"self":[{"href":"https:\/\/retroramblings.net\/index.php?rest_route=\/wp\/v2\/posts\/1138","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/retroramblings.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/retroramblings.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/retroramblings.net\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/retroramblings.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1138"}],"version-history":[{"count":3,"href":"https:\/\/retroramblings.net\/index.php?rest_route=\/wp\/v2\/posts\/1138\/revisions"}],"predecessor-version":[{"id":1141,"href":"https:\/\/retroramblings.net\/index.php?rest_route=\/wp\/v2\/posts\/1138\/revisions\/1141"}],"wp:attachment":[{"href":"https:\/\/retroramblings.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1138"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/retroramblings.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1138"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/retroramblings.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1138"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}