{"id":412,"date":"2013-04-15T23:55:39","date_gmt":"2013-04-15T23:55:39","guid":{"rendered":"http:\/\/retroramblings.net\/?p=412"},"modified":"2013-04-15T23:55:39","modified_gmt":"2013-04-15T23:55:39","slug":"projectxg-redux","status":"publish","type":"post","link":"https:\/\/retroramblings.net\/?p=412","title":{"rendered":"ProjectXG Redux"},"content":{"rendered":"<p>Anyone remember CU Amiga Magazine&#8217;s &#8220;ProjectXG&#8221;?\u00a0 This was a DIY project they ran, based on a hack that was published on Aminet, to interface a Waveblaster MIDI daughterboard to the Amiga&#8217;s serial port, to provide a pretty good quality MIDI tone module.<\/p>\n<p>The daughterboard most commonly used for this project was Yamaha&#8217;s DB50XG, though any card which attached to a &#8220;Waveblaster&#8221; header could be used.\u00a0 (Googling Waveblaster now, however, will find you a Yamaha product of <a href=\"http:\/\/en.wikipedia.org\/wiki\/Yamaha_Wave_Blaster\">quite a different nature<\/a>.)<\/p>\n<p>The DB50XG&#8217;s successor, the DB60XG was manufactured under license by NEC as the XR385, and this seems to be the easiest such card to find these days.\u00a0 It&#8217;s very similar to the DB50XG, it just has some very subtly different voicing, and can apply its DSP effects to incoming audio as well as its own sounds.<\/p>\n<p>Having built a ProjectXG many years ago, then selling it a year or so back and promptly building another one, I naturally wanted to interface a Waveblaster card to one of my Minimig variants, and listen to some old MIDI files again.<br \/>\n<!--more--><a href=\"http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/XGCard.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-413\" alt=\"XGCard\" src=\"http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/XGCard.jpg\" width=\"500\" height=\"679\" srcset=\"https:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/XGCard.jpg 500w, https:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/XGCard-220x300.jpg 220w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><\/p>\n<p>So what did I have to do to get this working?\u00a0 In the middle of the picture you can see a PicoPSU.\u00a0 These ingenious little devices are designed for powering small form factor computers, and will generate the various voltages required from a single 12v power source.\u00a0 In this instance, I&#8217;m using it to generate the +5v, +12 and -12v required by the XR385 in the foreground, and also taking +5v from the Molex connector to power the FPGA board in the background.<\/p>\n<p>The stripboard attached to the ATX connector contains a bog-standard MIDI input stage &#8211; one resistor, one diode and an opto-isolator &#8211; and also a capacitor to provide a delayed reset pulse, without which the XR385 won&#8217;t start up.<\/p>\n<p>The breadboard at the back contains a simple MIDI output stage &#8211; again very standard &#8211; just a BC547 driven by the FPGA pin.\u00a0 (Because the BC547 inverts the signal, I also invert it in the FPGA core &#8211; I couldn&#8217;t be bothered to rig up a second transistor and invert it on the breadboard!)<\/p>\n<p>So here a few snippets of music played back using my own DeliMIDI player for Delitracker, the Minimig core and an XR385.<\/p>\n<p><!--[if lt IE 9]><script>document.createElement('audio');<\/script><![endif]-->\n<audio class=\"wp-audio-shortcode\" id=\"audio-412-1\" preload=\"none\" style=\"width: 100%;\" controls=\"controls\"><source type=\"audio\/mpeg\" src=\"http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/Children_Excerpt.mp3?_=1\" \/><a href=\"http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/Children_Excerpt.mp3\">http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/Children_Excerpt.mp3<\/a><\/audio><br \/>\n<audio class=\"wp-audio-shortcode\" id=\"audio-412-2\" preload=\"none\" style=\"width: 100%;\" controls=\"controls\"><source type=\"audio\/mpeg\" src=\"http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/Machine_Excerpt.mp3?_=2\" \/><a href=\"http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/Machine_Excerpt.mp3\">http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/Machine_Excerpt.mp3<\/a><\/audio><br \/>\n<audio class=\"wp-audio-shortcode\" id=\"audio-412-3\" preload=\"none\" style=\"width: 100%;\" controls=\"controls\"><source type=\"audio\/mpeg\" src=\"http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/TakeAPebble_Excerpt.mp3?_=3\" \/><a href=\"http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/TakeAPebble_Excerpt.mp3\">http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/TakeAPebble_Excerpt.mp3<\/a><\/audio><br \/>\n<audio class=\"wp-audio-shortcode\" id=\"audio-412-4\" preload=\"none\" style=\"width: 100%;\" controls=\"controls\"><source type=\"audio\/mpeg\" src=\"http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/SuplexHold.mp3?_=4\" \/><a href=\"http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/SuplexHold.mp3\">http:\/\/retroramblings.net\/wp-content\/uploads\/2013\/04\/SuplexHold.mp3<\/a><\/audio><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Anyone remember CU Amiga Magazine&#8217;s &#8220;ProjectXG&#8221;?\u00a0 This was a DIY project they ran, based on a hack that was published on Aminet, to interface a Waveblaster MIDI daughterboard to the Amiga&#8217;s serial port, to provide a pretty good quality MIDI &hellip; <a href=\"https:\/\/retroramblings.net\/?p=412\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,4,7],"tags":[],"class_list":["post-412","post","type-post","status-publish","format-standard","hentry","category-amiga","category-fpga","category-music"],"_links":{"self":[{"href":"https:\/\/retroramblings.net\/index.php?rest_route=\/wp\/v2\/posts\/412","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=412"}],"version-history":[{"count":9,"href":"https:\/\/retroramblings.net\/index.php?rest_route=\/wp\/v2\/posts\/412\/revisions"}],"predecessor-version":[{"id":426,"href":"https:\/\/retroramblings.net\/index.php?rest_route=\/wp\/v2\/posts\/412\/revisions\/426"}],"wp:attachment":[{"href":"https:\/\/retroramblings.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=412"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/retroramblings.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=412"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/retroramblings.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=412"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}