{"id":1217,"date":"2017-04-16T14:53:16","date_gmt":"2017-04-16T13:53:16","guid":{"rendered":"http:\/\/www.randomorbit.co.uk\/?p=1217"},"modified":"2017-04-16T14:53:16","modified_gmt":"2017-04-16T13:53:16","slug":"retrochallenge-20174-interak-cf-card-part-3","status":"publish","type":"post","link":"https:\/\/www.randomorbit.co.uk\/?p=1217","title":{"rendered":"Retrochallenge 2017\/4 \u2013 Interak CF card \u2013 Part 3"},"content":{"rendered":"

Things are a little weird as I suggested in my previous post.<\/a><\/p>\n

I have the CF card installed and if I use the ROM monitor in the Interak to access it through a series of P<\/strong>ort<\/em> commands, I can see what appears to be sensible data. If, however I use a piece of Z80 assembly language, I never see the CF card become ready.<\/p>\n

I have tried my own code and two other variants found on the web.<\/p>\n

Let me show you what I mean. This snippet came from Scott Baker’s website…<\/p>\n

1069<\/span>:         \tWAITDRQ:\r\n1069<\/span>: F5      \t        PUSH<\/span>    AF<\/span>\r\n106A:         \tWAITDRQLP:\r\n106A: DB67    \t        in<\/span> \tA<\/span>,<\/span>(<\/span>I7)<\/span>\r\n106C: E608    \t        AND<\/span> \t08H\r\n106E: FE08    \t        cp<\/span> \t08H\r\n1070<\/span>: 20F8    \t        JR<\/span>\tNZ,<\/span> WAITDRQLP\r\n1072<\/span>: F1      \t        POP<\/span> \tAF<\/span>\r\n1073<\/span>: C9      \t        RET<\/span>\r\n<\/pre>\n
To use this, I have set up the sector and all other parameters needed for a disk read. If I run this routine, it never finishes. breaking the code at 0x106C shows that the accumulator is either 0x40 or 0x41. Which means “Drive ready” or “Drive ready + error”.<\/p>\n
However, if I use “P 67” at the monitor, I get “0x58” which means “Drive ready + Drive seek complete + Data request ready”.<\/p>\n
I can run from 0x106A to 106C again and again I see 0x40 or 0x41 in the accumulator. If I use “P67” again, again I see 0x58.<\/p>\n
Can anyone see the deliberate mistake because I can’t \ud83d\ude41<\/p>\n","protected":false},"excerpt":{"rendered":"
Things are a little weird as I suggested in my previous post. I have the CF card installed and if I use the ROM monitor in the Interak to access it through a series of Port commands, I can see what appears to be sensible data. If, however I use a piece of Z80 assembly … Continue reading Retrochallenge 2017\/4 \u2013 Interak CF card \u2013 Part 3<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","footnotes":""},"categories":[47,122,33,125],"tags":[],"class_list":["post-1217","post","type-post","status-publish","format-standard","hentry","category-c93-blog-posts","category-interak","category-c84-retro-tech","category-retrochallenge-20174"],"featured_image_src":null,"author_info":{"display_name":"andy","author_link":"https:\/\/www.randomorbit.co.uk\/?author=1"},"_links":{"self":[{"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/1217","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1217"}],"version-history":[{"count":1,"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/1217\/revisions"}],"predecessor-version":[{"id":1218,"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/1217\/revisions\/1218"}],"wp:attachment":[{"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1217"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1217"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1217"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}