{"id":2055,"date":"2012-11-27T21:49:27","date_gmt":"2012-11-27T19:49:27","guid":{"rendered":"http:\/\/www.kameli.net\/marq\/?p=2055"},"modified":"2012-11-28T07:59:37","modified_gmt":"2012-11-28T05:59:37","slug":"zx-spectrum-keyboard-visualized","status":"publish","type":"post","link":"http:\/\/www.kameli.net\/marq\/?p=2055","title":{"rendered":"ZX Spectrum Keyboard Visualized"},"content":{"rendered":"<p>Ok, I got interested in the keyboard membrane issue: which wires are actually the columns and which are the rows? If a row or column of keys doesn&#8217;t work, which wire is to blame? To help the debugging process I made a quick visualization (hey, don&#8217;t be too harsh on the aesthetics, I only <em>teach<\/em> at a design school) showing the traces and the corresponding keys.<\/p>\n<p><a href=\"http:\/\/www.kameli.net\/marq\/wp-content\/uploads\/2012\/11\/membrein-visu.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-thumbnail wp-image-2056\" title=\"membrein-visu\" src=\"http:\/\/www.kameli.net\/marq\/wp-content\/uploads\/2012\/11\/membrein-visu-150x150.png\" alt=\"Membrane visualization\" width=\"150\" height=\"150\" \/><\/a><\/p>\n<p>Some curious things popped up immediately. First of all, the columns are symmetric: the leftmost column continues to the right end and so on. Another interesting finding was that the rows are not in a very logical order if you consider the wires going to the motherboard. The first three are nicely mapped but then there&#8217;s a sudden jump to the first row of the right side. The maximum amount of combinations possible with 5 by 8 traces is 40, which is exactly the number of keys on the keyboard.<\/p>\n<p><em>edit: <a href=\"http:\/\/www.1000bit.it\/support\/manuali\/sinclair\/zxspectrum\/sm\/matrix.gif\">The Service Manual matrix image<\/a> explains the workings nicely from another perspective.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Ok, I got interested in the keyboard membrane issue: which wires are actually the columns and which are the rows? If a row or column of keys doesn&#8217;t work, which wire is to blame? To help the debugging process I made a quick visualization (hey, don&#8217;t be too harsh on the aesthetics, I only teach [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22,15,26],"tags":[],"class_list":["post-2055","post","type-post","status-publish","format-standard","hentry","category-laitteet","category-retro","category-visuaalit"],"_links":{"self":[{"href":"http:\/\/www.kameli.net\/marq\/index.php?rest_route=\/wp\/v2\/posts\/2055","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.kameli.net\/marq\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.kameli.net\/marq\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.kameli.net\/marq\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.kameli.net\/marq\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2055"}],"version-history":[{"count":7,"href":"http:\/\/www.kameli.net\/marq\/index.php?rest_route=\/wp\/v2\/posts\/2055\/revisions"}],"predecessor-version":[{"id":2065,"href":"http:\/\/www.kameli.net\/marq\/index.php?rest_route=\/wp\/v2\/posts\/2055\/revisions\/2065"}],"wp:attachment":[{"href":"http:\/\/www.kameli.net\/marq\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2055"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.kameli.net\/marq\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2055"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.kameli.net\/marq\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2055"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}