[{"data":1,"prerenderedAt":200},["ShallowReactive",2],{"project-37979841":3},{"id":4,"name":5,"line":6,"line_source":7,"title":8,"url":9,"domain":10,"maker":11,"posted_at":12,"year":13,"points":14,"comments":15,"rank_in_year":16,"shown_in_year":17,"top":18,"tier":19,"category":20,"subcategory":21,"format":22,"keywords":23,"reception":28,"sentiment":29,"stance_mix":30,"scored_comments":34,"aspects":35,"strip":38,"post_text":40,"what":41,"said":66,"maker_in_thread":110,"shape":118,"grid":122,"attempts":159,"same_week":164,"maker_shows":32,"maker_hidden":192,"reader_version":193,"card":194},"37979841","eepromlogic","Use an EEPROM as Programmable Logic","title","Show HN: Use an EEPROM as Programmable Logic","https:\u002F\u002Fgithub.com\u002FDusteDdk\u002Feepromlogic","github.com","dusted",1698015592,2023,22,15,1608,3109,52,"shown","hardware","programmable logic","other",[24,21,25,26,27],"eeprom","lookup table","prom","logic design","curious",-0.083,{"positive":31,"neutral":32,"mixed":31,"critical":33},0,4,1,5,{"idea":36,"docs":37},{"positive":31,"critical":33},{"positive":31,"critical":31},[31,31,31,31,39,33,31,31,31,31,39,39,31,39,31],3,null,{"problem":42,"audience":40,"pricing":40,"motivation":52,"time_to_build":40,"stack":56,"openness":65,"stage":65,"team_size":65},{"value":43,"source":44,"evidence":45},"Implements combinational logic using EEPROM lookup tables instead of gates or FPGAs.","maker",[46,49],{"id":47,"by":11,"text":48},"37983433","Yes, however, it's best suited for the complex parts (logic that needs a lot of inputs and few outputs) due to the fact that the eeproms it generates data for are arranged as 8…",{"id":50,"by":11,"text":51},"37983469","Definitely, if you just need some nand gates, this is probably the worst way of doing it, where it can be of some use is when you want to describe more complex behavior, where…",{"value":53,"source":44,"evidence":54},"Needed logic for a DEC J-11 CPU build while staying period-correct without an FPGA.",[55],{"id":47,"by":11,"text":48},[57],{"value":58,"source":59,"evidence":60},"Lisp","commenter",[61],{"id":62,"by":63,"text":64},"37993733","kjs3","This was routinely done for 2 decades or so. Small (e.g. 32x8, 256x8) fast bipolar proms were extremely common for things like address decoders in the 70s and 80s. I've used fast…","unknown",{"praise":67,"objections":73,"requests":85,"questions":86,"alternatives":94},[68],{"value":69,"source":59,"evidence":70},"Clever approach and useful for complex logic with many inputs.",[71,72],{"id":62,"by":63,"text":64},{"id":50,"by":11,"text":51},[74,78],{"value":75,"source":44,"evidence":76},"Slow compared to discrete gates; EEPROM access time limits speed.",[77],{"id":47,"by":11,"text":48},{"value":79,"source":59,"evidence":80},"Simpler to use plain NAND gates for basic logic.",[81],{"id":82,"by":83,"text":84},"37983196","royjacobs","It can function as a NAND gate, and anything can be built out of NAND gates. At that point it might be simpler to just use actual NAND gates though :)",[],[87],{"value":88,"source":59,"evidence":89},"Could it be used to build a minimal Ben Eater style CPU?",[90],{"id":91,"by":92,"text":93},"37983015","c7DJTLrn","Could this be used to build a super minimalistic Ben Eater style CPU?",[95,99,106],{"value":96,"source":44,"evidence":97},"PLA or GAL devices",[98],{"id":47,"by":11,"text":48},{"value":100,"source":59,"evidence":101},"RAM as programmable logic",[102],{"id":103,"by":104,"text":105},"37983786","pomatic","Another interesting strategy is to use RAM as programmable logic. It's faster, which can be beneficial in some situations, and is obviously easy to change on the fly. The catch…",{"value":107,"source":59,"evidence":108},"Registered PROMs and fast bipolar PROMs",[109],{"id":62,"by":63,"text":64},{"comments":32,"answered":111,"key":112},2,[113,116,117],{"id":114,"text":115},"38010158","Interesting idea! With DRAM it becomes slightly funky because you want to allow for refresh, but with SRAM it's certainly a cool idea to get more speed, if you can live with the…",{"id":50,"text":51},{"id":47,"text":48},{"commenters":119,"max_depth":32,"maker_replies":32,"first_comment_mins":120,"lifespan_hours":121},9,576,56,[123,127,129,130,132,134,136,138,141,144,145,149,152,154,157],[124,31,31,125,126,31],"37990067","other\u002Fneutral\u002Fnone","matja",[62,33,31,128,63,31],"other\u002Fneutral\u002Fidea",[103,111,31,128,104,31],[114,111,31,131,11,33],"project\u002Fneutral\u002Fperformance",[91,39,39,133,92,31],"project\u002Fneutral\u002Fidea",[82,39,33,135,83,31],"project\u002Fcritical\u002Fidea",[50,39,31,137,11,33],"maker\u002Fneutral\u002Fidea",[139,39,31,125,140,31],"37983276","madmulita",[142,39,31,143,92,31],"37983523","other\u002Fpositive\u002Fnone",[47,39,31,131,11,33],[146,39,39,147,148,31],"37990473","maker\u002Fneutral\u002Fdocs","RetroTechie",[150,39,39,151,63,31],"37993931","maker\u002Fneutral\u002Fnone",[153,39,31,151,11,33],"37995596",[155,39,39,133,156,31],"37984830","Joker_vD",[158,39,31,143,92,31],"37988777",[160,163],{"id":161,"t":162,"points":33,"comments":31},"37963667",1697856596,{"id":4,"t":12,"points":14,"comments":15},[165,170,174,178,183,188],{"id":166,"name":167,"points":168,"category":169},"38012032","OpenAPI DevTools",811,"dev_tools",{"id":171,"name":172,"points":173,"category":169},"37943931","Autotab",376,{"id":175,"name":176,"points":177,"category":169},"37981683","Pypipe",213,{"id":179,"name":180,"points":181,"category":182},"38006814","Restaurants in Peace",181,"consumer_social",{"id":184,"name":185,"points":186,"category":187},"37956065","CFR[]",176,"creative",{"id":189,"name":190,"points":191,"category":169},"37995761","Revert",168,false,"v2",{"id":195,"name":5,"line":6,"ai":192,"cat":20,"year":13,"points":14,"comments":15,"rec":28,"s":196,"top":18,"kw":197,"maker":11,"domain":10,"tier":19,"attempts":111,"strip":198,"url":9,"mix":199,"praise":69,"objection":75,"sub":21},37979841,-0.08,[24,21,25,26,27],"000031000033030",[31,32,31,33],1794036643550]