{"id":22,"date":"2010-02-08T20:44:29","date_gmt":"2010-02-08T20:44:29","guid":{"rendered":"http:\/\/mitat.tuu.fi\/?p=22"},"modified":"2010-03-17T20:53:02","modified_gmt":"2010-03-17T20:53:02","slug":"midi-signal","status":"publish","type":"post","link":"http:\/\/mitat.tuu.fi\/?p=22","title":{"rendered":"MIDI signal"},"content":{"rendered":"<p style=\"text-align: left;\">MIDI signal in oscilloscope. Inverted serial 31200 bits per second. Captured from USB-&gt;MIDI adapter (SWIS). First bit time is about 32us (31.2us = microsecond\u00a0). Voltage difference was 3.92V.<\/p>\n<p style=\"text-align: left;\">\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter\" title=\"MIDI\" src=\"http:\/\/mitat.tuu.fi\/wp-content\/uploads\/2010\/02\/midi.jpg\" alt=\"\" width=\"320\" height=\"234\" \/><\/p>\n<p style=\"text-align: left;\">A great page describing MIDI: http:\/\/www.tigoe.net\/pcomp\/code\/serial-communication\/midi which describes MIDI like:<\/p>\n<blockquote>\n<p style=\"text-align: left;\">&#8220;MIDI is a serial communications protocol, operating at 31,250 bits per second. Each byte has 8 bits, plus a start bit and a stop bit. It operates at 5 volts DC. The standard MIDI connector is a 5-pin DIN connector, and usually all connectors on the device are female, and both ends of a MIDI cable are male.&#8221;<\/p>\n<\/blockquote>\n<p style=\"text-align: left;\">From here http:\/\/home.roadrunner.com\/~jgglatt\/tech\/midispec.htm :<\/p>\n<ul>\n<li>MIDI is an asynchronous serial interface.<\/li>\n<li>The baud rate is 31.25 Kbaud (+\/- 1%).<\/li>\n<li>There is 1 start bit, 8 data bits, and 1 stop bit (ie, 10 bits total), for a period of 320 microseconds per serial byte.<\/li>\n<li>The MIDI circuit is current loop, 5 mA.<\/li>\n<li>Logic 0 is current ON.<\/li>\n<li>To avoid grounding loops and subsequent data errors, the input is opto-isolated. It requires less than 5 mA to turn on. The Sharp PC-900 and HP 6N138 optoisolators are satisfactory devices. Rise and fall time for the optoisolator should be less than 2 microseconds.<\/li>\n<li>The standard connector used for MIDI is a 5 pin DIN.<\/li>\n<li>Separate jacks (and cable runs) are used for input and output, clearly marked on a given device (ie, the MIDI IN and OUT are two separate DIN female panel mount jacks).<\/li>\n<li>50 feet is the recommended maximum cable length.<\/li>\n<li>Cables are shielded twisted pair, with the shield connecting pin 2 at both ends.<\/li>\n<li>The pair is pins 4 and 5. Pins 1 and 3 are not used, and should be left unconnected.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>MIDI signal in oscilloscope. Inverted serial 31200 bits per second. Captured from USB-&gt;MIDI adapter (SWIS). First bit time is about 32us (31.2us = microsecond\u00a0). Voltage difference was 3.92V. A great page describing MIDI: http:\/\/www.tigoe.net\/pcomp\/code\/serial-communication\/midi which describes MIDI like: &#8220;MIDI is a serial communications protocol, operating at 31,250 bits per second. Each byte has 8 bits, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7,8,9],"tags":[],"class_list":["post-22","post","type-post","status-publish","format-standard","hentry","category-electronics","category-measured","category-oscilloscoped"],"_links":{"self":[{"href":"http:\/\/mitat.tuu.fi\/index.php?rest_route=\/wp\/v2\/posts\/22","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/mitat.tuu.fi\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/mitat.tuu.fi\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/mitat.tuu.fi\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/mitat.tuu.fi\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=22"}],"version-history":[{"count":10,"href":"http:\/\/mitat.tuu.fi\/index.php?rest_route=\/wp\/v2\/posts\/22\/revisions"}],"predecessor-version":[{"id":28,"href":"http:\/\/mitat.tuu.fi\/index.php?rest_route=\/wp\/v2\/posts\/22\/revisions\/28"}],"wp:attachment":[{"href":"http:\/\/mitat.tuu.fi\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=22"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/mitat.tuu.fi\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=22"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/mitat.tuu.fi\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=22"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}