2026-04-16T10:18:54Z https://yabu.me Electrotopia⚡️ https://yabu.me/npub1g8rkdfne0p6ktkkylyr25fzdpm7sctn86aydsl29h0lcc9gd6desakwa56 https://mastodon.nl/system/accounts/avatars/110/564/532/945/290/105/original/96582ee0a6804987.gif https://mastodon.nl/system/accounts/avatars/110/564/532/945/290/105/original/96582ee0a6804987.gif https://yabu.me/nevent1qqst22x0xhd6hg4mpspunuu8tqdmp6maxf5pnhslvtn6haxsw2sn9mczypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxqqxdpz Anyone else ever notice that DIP-40 chips are never boring?<br/><br/>Like if you see a DIP-40 on a board, you know it&#39;s something interesting!<br/> <img src="https://mastodon.nl/system/media_attachments/files/115/151/205/975/413/614/original/1acb074b063454e9.jpg"> <br/> 2025-09-05T10:26:15Z https://yabu.me/nevent1qqspemxms2qtt3kf9r2c64jj6y2c946cu5za7xgslp77xngvufuk75gzypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxdwuka4 In reply to <a href='/nevent1qqsx25hcer3yugafg68j6wy8hlex9grjyuyru33x6lqpqth65cehpfs5xjl6w'>nevent1q…jl6w</a><br/>_________________________<br/><br/>yep OG VGA textmode is 720 by 400...pretty cursed in my opinion. 9 horizontal bits per character🤮 2025-07-01T21:48:28Z https://yabu.me/nevent1qqszfhg6lgze3vz2unpmgq8dn90xy2j5548pdtn0wtq3w8slah78m9qzypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxkjnmga Three generations of keyboard interface cards for my Z80 machine. <br/><br/>First: Simple interrupt logic and two buffer ICs for reading X &amp; Y signals from the keyboard matrix.<br/><br/>Second: Added connections and logic to also read two rotary encoders. <br/><br/>Third: Replaced the buffers with latches that are disabled when read (reduces chances of metastability) and reimplemented interrupt logic as a state machine. <br/><br/>Very happy with the final card. Represents a serious leap in engineering compared to my original.<br/> <img src="https://mastodon.nl/system/media_attachments/files/114/777/913/259/123/586/original/90565de918ac3cea.jpg"> <br/> <img src="https://mastodon.nl/system/media_attachments/files/114/777/913/767/886/053/original/a6122d9fd632a47f.jpg"> <br/> 2025-07-01T12:23:22Z https://yabu.me/nevent1qqswmm4s22yg9stj04erfa27znyz64utgwfqmr93x00xzjll88ckumszypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxtsl4kj In reply to <a href='/nevent1qqsfaas7lff5fd9qgk34ssnm0hww68zpd66uwkf9rrl8sh0sdecssnggwsgqw'>nevent1q…sgqw</a><br/>_________________________<br/><br/>decimal machines were pretty common in early computing. People weren&#39;t used to binary yet so lots of machines used BCD for arithmetic because it was easier for humans to understand and debug.<br/><br/>The extra hardware cost wasn&#39;t worth it though, so eventually pure binary machines prevailed. 2025-05-28T11:41:24Z https://yabu.me/nevent1qqs9z5pvw5y3ye8dv6spm3zcjtdd40ph6e8dr3eqeuallucy6cyps3gzypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxvgu292 In 1981 #IBM got the legendary Paul Rand to redesign their logo. He did not disappoint.<br/><br/>Eye Bee M<br/> <img src="https://mastodon.nl/system/media_attachments/files/114/318/484/474/095/730/original/eede614b43b4373b.jpg"> <br/> 2025-04-11T08:55:19Z https://yabu.me/nevent1qqs99gjqye46chvm8jaszaklgef047cr29xxt50z7lcrfga8ujhmw8czypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxd9sd7g In reply to <a href='/nevent1qqsdvjxdwtyusze3phn78cevlcr5yh54czh0x639a9hz0h9mhm4sngcwe0uwr'>nevent1q…0uwr</a><br/>_________________________<br/><br/>it&#39;s just 640 with double wide pixels 2025-03-27T19:20:10Z https://yabu.me/nevent1qqsy42ql8c4jw9wjpzhqvwvcyqk08rwhyh7tw7dzfdsyygd9cf92e3czypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhx5klzta By designing the icons for the 1984 #macintosh, Susan Kare added a much needed personal touch to the computer industry.<br/><br/>Her icons were incredibly descriptive given they were just 32 × 32 pixels, and at that resolution she may also have been paid the most money-per-pixel of any digital artist in history! (I hear apple did pay her well)<br/><br/>Happy #marchinosh<br/> <img src="https://mastodon.nl/system/media_attachments/files/114/230/216/763/118/447/original/ced36297f4cdf645.jpg"> <br/> <img src="https://mastodon.nl/system/media_attachments/files/114/230/217/435/912/646/original/00c94d8a13bc73fa.jpg"> <br/> 2025-03-26T19:02:17Z https://yabu.me/nevent1qqsfnd8wvpssfq82paw6zsl2usswmhsxmn9urfevkd9tc0uq54eh43czypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxq3zf38 In reply to <a href='/nevent1qqstuzpgsangwm322d53rj728ewm9v6l0q8q545q3eg9sukat34qngsqsyqm5'>nevent1q…yqm5</a><br/>_________________________<br/><br/>oh I see. I just explained it badly. <br/><br/>The interrupt signal is generated by the ANDing them. <br/><br/>The CPU reads the raw inputs (through schmitt triggers) 2025-03-08T22:56:05Z https://yabu.me/nevent1qqsywrn0hfl9vshpxnq8u6n5p8dfrvfz0kulfuvquu52vp9f2has3pgzypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhx47kjrz In reply to <a href='/nevent1qqstuzpgsangwm322d53rj728ewm9v6l0q8q545q3eg9sukat34qngsqsyqm5'>nevent1q…yqm5</a><br/>_________________________<br/><br/>when the first edge falls, the other with still be high and you&#39;re just looking at that to tell the direction. 2025-03-08T22:53:23Z https://yabu.me/nevent1qqsvpxc8clm7x8ynncfhr8l7xsdascle0qpauu8tnltglthej39khyqzypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxesae30 In reply to <a href='/nevent1qqswg2tkw79f7l62vmckdujcxm4epgj0hvzy6rydv9ewm87579v5hucepphlw'>nevent1q…phlw</a><br/>_________________________<br/><br/>thanks, I&#39;ll be writing drivers for it soon so this&#39;ll be useful. 2025-03-08T22:41:40Z https://yabu.me/nevent1qqsqzl0ll827cr9sgwjgd0mr0qjufmncev3r09puty7fh34c5vkv4wczypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxm4xmjg In reply to <a href='/nevent1qqsvmzafxevkj5d6e3x7akeuls0ld3mtwaa0ps3fzkzuwhzh49u9a8clxq7rz'>nevent1q…q7rz</a><br/>_________________________<br/><br/>all the inputs are active low, so I&#39;m just ANDing them all together and the negative edge generates an interrupt. 2025-03-08T22:40:24Z https://yabu.me/nevent1qqsg2e4xnup4umx59m69v2gm80m55cek92y0crp6wadf95zy8pa2ekgzypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhx5drr57 In reply to <a href='/nevent1qqsxxqxmq0y2n3pmrupshswkslxrlnyzefs687xqsna8geg20t0hfxspgzv9f'>nevent1q…zv9f</a><br/>_________________________<br/><br/><a href="https://en.m.wikipedia.org/wiki/Rotary_encoder">https://en.m.wikipedia.org/wiki/Rotary_encoder</a> <br/><br/>^ look at the section on incremental encoders.<br/><br/>The interrupt just causes it to store the outputs of the encoders (it&#39;s visible as an 8-bit input port), then schedule further processing the next time the OS is called. <br/><br/>The Z80 is running at 8MHz, pretty snappy, so the interrupt response time should be quick enough provided it&#39;s not serving lots of higher priority interrupts...but yes it is cutting it closer than I&#39;d like. 2025-03-08T22:11:37Z https://yabu.me/nevent1qqsgjqgys0n4jape0gchawu0ugzllf695whmv6u2enxlk8rvl2rsdjczypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxzqvt05 In reply to <a href='/nevent1qqsvnccvltrju4pgky7f6n5kpayzlkclglye7u9ydpmczxaavn90juqh20j5d'>nevent1q…0j5d</a><br/>_________________________<br/><br/>and yeah the backup battery is a 9V. <br/><br/>I designed the buck converter to accept 9V from the wall anyway so this was another an easy addition. 2025-03-08T22:01:48Z https://yabu.me/nevent1qqs03pkccs9uts30292yavh69ade4sksta20jehv2wmyj90r4rs4pnqzypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhx3aeaq3 In reply to <a href='/nevent1qqsvnccvltrju4pgky7f6n5kpayzlkclglye7u9ydpmczxaavn90juqh20j5d'>nevent1q…0j5d</a><br/>_________________________<br/><br/>no ADCs. They&#39;re rotary encoders so their output is digital.<br/><br/>All I&#39;m doing is schmitt triggering the inputs and adding a bit of logic to generate an interrupt when it detects a low transition.<br/><br/>Most of the interrupt logic is shared with the keyboard anyway so this addition hasn&#39;t increased the chip count much. 2025-03-08T21:59:43Z https://yabu.me/nevent1qqsvntg09hxnxamnh2hjnfkpul08zj9f48nn4hwk39fafft6tmg4llqzypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxgm6n93 In reply to <a href='/nevent1qqsgz2lztnmxvs60e3dj7x3q9cwuyzpey6nrm3dpn2qg6qgqpr7mn7gtwr3rk'>nevent1q…r3rk</a><br/>_________________________<br/><br/>thanks. <br/><br/>I was surprised about how easy it was. Everyone with an interest in electronics could (and should) apply for their foundation licence. It&#39;s only a couple of evenings of work. 2025-03-08T21:55:32Z https://yabu.me/nevent1qqs9hv67r523fkuy674n38h4dj9xc9ajgkpf6re8zfq9fnxhvjctsnszypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhx9tzs82 My #Z80 machine is getting some new input devices.<br/><br/>Watch this space!<br/><br/>#electronics #breadboard #homebrew<br/> <img src="https://mastodon.nl/system/media_attachments/files/114/128/997/854/812/460/original/c793dac0d6204f81.jpg"> <br/> 2025-03-08T21:46:35Z https://yabu.me/nevent1qqs2rwt9qh3cl0x3r6grw5ddxafqztddyy93dqsndwrnreq56rgjmsgzypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxdnwxzf I&#39;ve been meaning to get this done for a few years. So happy I finally found the time to do it!<br/><br/>🎙Callsign: M7TZC<br/><br/>#amateur #radio #foundation<br/> <img src="https://mastodon.nl/system/media_attachments/files/114/128/974/073/774/469/original/0acae9a80a988f06.jpg"> <br/> 2025-03-08T21:42:33Z https://yabu.me/nevent1qqsqccdgfu8zlxdv8z7pu2cmvjr9ghfkct4wcdxtavvucdssc6wv83gzypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhx66h733 In reply to <a href='/nevent1qqsdegn7dtk3hc7vf04sm3pg0mjnjfnhq3nhdg2l60f7s8nr075qzvshfkj5x'>nevent1q…kj5x</a><br/>_________________________<br/><br/>I&#39;ll take some of the MC34063s if they&#39;re still going?<br/><br/>It&#39;s a brilliant little chip! 2025-02-06T23:00:44Z https://yabu.me/nevent1qqsyl9s37w2kzrdcwjpjvy4j9q8srrcv4l50tvwywzjw7k7wmuemlmczypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhx56qg53 In reply to <a href='/nevent1qqsxu5u7427a7f0g0m5tvajrmus9hy8f0hfywcmv0mdmsjyluyqaz8quk4e7j'>nevent1q…4e7j</a><br/>_________________________<br/><br/>i actually use a trick like this for my buffers.<br/><br/>If you put the buffer on a page boundary then you only need to reload the low half of the pointer (1 byte) as apposed to the full 16-bits. 2025-01-21T06:37:51Z https://yabu.me/nevent1qqsykyzkft2050fjk9wjqex5qs2wjdx3kfe88m5zn68sg64qdls2h0gzypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhxqpnv6m In reply to <a href='/nevent1qqszele0au9jg60cgu8egsd3fgd38xsre905rqyfxjycph7n70qcevch7sauq'>nevent1q…sauq</a><br/>_________________________<br/><br/>yeah Set and Reset aren&#39;t synchronous. The output will change the moment you pull those inputs low, they don&#39;t use the clock. 2024-12-19T23:07:55Z https://yabu.me/nevent1qqsrhvx7f52mqvuf8cz7fuux63zytxn2cch2v0uy4g8uejawdk8r02gzypquwe4x09u82ew6cnusd23yf5806rpwvlt53kragkallrq4phfhx89zw7u Finally got my 320 by 200 #VGA video card PCBs last week. Glad to be off the breadboard!<br/><br/>Here&#39;s a view of my hex editor on my #Z80 machine using it.<br/><video controls width="100%" class="max-h-[90vh] bg-neutral-300 dark:bg-zinc-700"><source src="https://mastodon.nl/system/media_attachments/files/111/524/166/911/767/775/original/492c0e0dcb4a27c0.mp4"></video><br/> 2023-12-04T21:07:30Z