{"id":613,"date":"2013-07-31T18:06:58","date_gmt":"2013-07-31T18:06:58","guid":{"rendered":"http:\/\/retroramblings.net\/?p=613"},"modified":"2013-07-31T23:19:24","modified_gmt":"2013-07-31T23:19:24","slug":"experience-gained","status":"publish","type":"post","link":"https:\/\/retroramblings.net\/?p=613","title":{"rendered":"“Experience gained…"},"content":{"rendered":"

…is directly proportional to the value of equipment destroyed!”<\/p>\n

I don’t know who first coined this phrase, but it’s always struck a chord with me.<\/p>\n

I came close to gaining lots of experience in the last week!
\n<\/p>\n

Having attached the MicroSD socket to the Vampire500 board, I was slightly disappointed to find that I couldn’t get any response from a MicroSD card – which I found to be rather hot when I ejected it!\u00a0 That’s never a good sign.<\/p>\n

Closer investigation revealed a layout error on the PCB; the pins were routed correctly for a traditional SD socket, but MicroSD sockets have a subtly different pinout! (http:\/\/elasticsheep.com\/2010\/01\/reading-an-sd-card-with-an-atmega168\/<\/a>)<\/p>\n

After some thought, it occurred to me that the simplest solution to this would be to abandon the MicroSD socket completely, and hardwire an SD-to-MicroSD adapter to the board!<\/p>\n

\"DSC_7438\"<\/a><\/p>\n

OK so it’s ugly, but it should work!<\/p>\n

On firing up the board again, I found that I could read the partition table off the card, but that my programs were crashing randomly before doing anything useful – and the Amiga accelerator core had developed SDRAM errors too – so I figured I’d probably disturbed some solder joints on the FPGA or SDRAM chip by flexing the board while working on it.\u00a0 So I had the bright idea of refreshing the solder joints.<\/p>\n

This didn’t go smoothly.<\/p>\n

The pin pitch on the FPGA is significantly smaller than the SDRAM and MicroSD socket, so the confidence I’d built up in installing the MicroSD socket quickly drained away as I ended up with pins bridged, pins misaligned, and as I tried to rectify that, lifted pads!<\/p>\n

I’m pleased to report, however, that after a lot of patience, lots of application of flux-soaked solderwick, lots of gentle persuasion of pins with a sewing needle attached to a screwdriver, and lots of peering through a magnifying glass and singeing of eyebrows, the board seems to be restored to full health!<\/p>\n

\"Image0359\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

…is directly proportional to the value of equipment destroyed!” I don’t know who first coined this phrase, but it’s always struck a chord with me. I came close to gaining lots of experience in the last week!<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,4,8],"tags":[],"class_list":["post-613","post","type-post","status-publish","format-standard","hentry","category-amiga","category-fpga","category-hardware"],"_links":{"self":[{"href":"https:\/\/retroramblings.net\/index.php?rest_route=\/wp\/v2\/posts\/613","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=613"}],"version-history":[{"count":5,"href":"https:\/\/retroramblings.net\/index.php?rest_route=\/wp\/v2\/posts\/613\/revisions"}],"predecessor-version":[{"id":619,"href":"https:\/\/retroramblings.net\/index.php?rest_route=\/wp\/v2\/posts\/613\/revisions\/619"}],"wp:attachment":[{"href":"https:\/\/retroramblings.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=613"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/retroramblings.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=613"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/retroramblings.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=613"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}