{"id":103,"date":"2016-11-13T19:50:27","date_gmt":"2016-11-13T07:50:27","guid":{"rendered":"http:\/\/www.junofirst.com\/?p=103"},"modified":"2016-11-13T22:03:38","modified_gmt":"2016-11-13T10:03:38","slug":"sega-system-24-sd-card-progress-part-2","status":"publish","type":"post","link":"http:\/\/www.junofirst.com\/?p=103","title":{"rendered":"Sega System 24 SD Card progress Part 2"},"content":{"rendered":"<p>Swapped the switching FET to an open collector 7406 (I didn&#8217;t have an LS handy) and I was able to reduce the delay in the read considerably.<\/p>\n<p>Reading the directory from the SD card works which is cool.<\/p>\n<p>As the SD\/FAT code needs to run in the System24 bios, it all needs converting to 68k assembler. After a few evenings work, the code to interface to the sd card is written but still needs debugging on real hardware. FAT16\/FAT32 (or maybe just FAT32) code to be converted next.<\/p>\n<p>The beauty of having the code working in C is that I can just replace each function with it&#8217;s assembler version and test each one. (after realising I needed to create some trampoline functions to convert the stack passing method to a more typical assembly call method.. unless there&#8217;s a compiler function to use register passing.. I wonder..)<\/p>\n<p><a href=\"http:\/\/www.junofirst.com\/wp-content\/uploads\/2016\/11\/20161113_224613.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-105\" src=\"http:\/\/www.junofirst.com\/wp-content\/uploads\/2016\/11\/20161113_224613-300x169.jpg\" alt=\"20161113_224613\" width=\"300\" height=\"169\" srcset=\"http:\/\/www.junofirst.com\/wp-content\/uploads\/2016\/11\/20161113_224613-300x169.jpg 300w, http:\/\/www.junofirst.com\/wp-content\/uploads\/2016\/11\/20161113_224613-768x432.jpg 768w, http:\/\/www.junofirst.com\/wp-content\/uploads\/2016\/11\/20161113_224613-1024x576.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a> <a href=\"http:\/\/www.junofirst.com\/wp-content\/uploads\/2016\/11\/20161113_224455.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-106\" src=\"http:\/\/www.junofirst.com\/wp-content\/uploads\/2016\/11\/20161113_224455-300x169.jpg\" alt=\"20161113_224455\" width=\"300\" height=\"169\" srcset=\"http:\/\/www.junofirst.com\/wp-content\/uploads\/2016\/11\/20161113_224455-300x169.jpg 300w, http:\/\/www.junofirst.com\/wp-content\/uploads\/2016\/11\/20161113_224455-768x432.jpg 768w, http:\/\/www.junofirst.com\/wp-content\/uploads\/2016\/11\/20161113_224455-1024x576.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Swapped the switching FET to an open collector 7406 (I didn&#8217;t have an LS handy) and I was able to reduce the delay in the read considerably. Reading the directory from the SD card works which is cool. As the SD\/FAT code needs to run in the System24 bios, it all needs converting to 68k &hellip; <a href=\"http:\/\/www.junofirst.com\/?p=103\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Sega System 24 SD Card progress Part 2<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-103","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"http:\/\/www.junofirst.com\/index.php?rest_route=\/wp\/v2\/posts\/103","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.junofirst.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.junofirst.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.junofirst.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.junofirst.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=103"}],"version-history":[{"count":3,"href":"http:\/\/www.junofirst.com\/index.php?rest_route=\/wp\/v2\/posts\/103\/revisions"}],"predecessor-version":[{"id":108,"href":"http:\/\/www.junofirst.com\/index.php?rest_route=\/wp\/v2\/posts\/103\/revisions\/108"}],"wp:attachment":[{"href":"http:\/\/www.junofirst.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=103"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.junofirst.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=103"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.junofirst.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=103"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}