{"version":1,"type":"story","url":"https://digestai.news/story/dave-plummer-builds-custom-ram-board-for-pdp-11-using-chatgpt","json":"https://digestai.news/story/dave-plummer-builds-custom-ram-board-for-pdp-11-using-chatgpt.json","markdown":"https://digestai.news/story/dave-plummer-builds-custom-ram-board-for-pdp-11-using-chatgpt.md","slug":"dave-plummer-builds-custom-ram-board-for-pdp-11-using-chatgpt","headline":"Dave Plummer builds custom RAM board for PDP-11 using ChatGPT","summary":"Dave Plummer, a former Microsoft engineer known for work on Task Manager and Windows Pinball, used ChatGPT and the EasyEDA online circuit simulator to design a new RAM board for the 1970s PDP‑11. The board fits on a Q‑Bus backplane and uses a Lattice MachXO2 FPGA model 2000HC as a memory controller, four ISSI 1 MB memory chips, a U2S I/O chip, DIP switches, and a few capacitors. The PDP‑11’s 22‑bit bus reserves the top 256 KB for I/O and ROM, and its word‑aligned memory access means the lowest address bit selects the byte lane. Plummer’s initial design returned only every second word, a classic PDP‑11 trap. After several attempts to flash‑program the FPGA, he corrected the logic in the FPGA code. He also experimented with a Raspberry Pi‑based solution via a QBone DEC interface board with a Beaglebone Black. The project illustrates how AI tools can aid in retro hardware design, though it remains a hobby effort without commercial release.","keyPoints":["Dave Plummer, former Microsoft engineer, builds a 4 MB RAM board for PDP‑11 using Lattice MachXO2 FPGA.","Board uses four ISSI 1 MB chips, U2S I/O chip, and EasyEDA circuit design.","PDP‑11 bus requires word‑aligned access, so memory returns every second word; fixed in FPGA code."],"whyItMatters":"The project shows how AI assistants like ChatGPT can help hobbyists design and troubleshoot complex retro hardware, reducing the learning curve for vintage computing enthusiasts. It also highlights the practical limits of legacy bus architectures and the need for careful logic design when interfacing modern components with old systems.","category":{"slug":"hardware","name":"Hardware & Compute","url":"https://digestai.news/category/hardware"},"entities":{"companies":["Microsoft","Lattice","ISSI","Tom's Hardware"],"models":["Lattice MachXO2","ChatGPT"],"people":["Dave Plummer","Bruno Ferreira"]},"firstPublishedAt":"2026-10-31T11:40:00Z","updatedAt":"2026-10-31T11:40:00Z","sourceCount":1,"hasPrimarySource":false,"sources":[{"outlet":"Tom's Hardware","title":"Veteran Microsoft engineer makes his own RAM from scratch using AI — custom FPGA board dodges extreme 1970s PDP-11 memory prices","url":"https://tomshardware.com/pc-components/ram/veteran-microsoft-engineer-makes-his-own-ram-from-scratch-using-ai-attempts-to-build-4mb-of-1970s-pdp-11-ram-from-scratch","publishedAt":"2026-10-31T11:40:00Z","type":"press","primary":false,"lead":true}],"sourceNotes":null,"discussions":[],"thread":null,"cite":{"text":"Digest AI, \"Dave Plummer builds custom RAM board for PDP-11 using ChatGPT\", 31 October 2026, https://digestai.news/story/dave-plummer-builds-custom-ram-board-for-pdp-11-using-chatgpt","publisher":"Digest AI","title":"Dave Plummer builds custom RAM board for PDP-11 using ChatGPT","datePublished":"2026-10-31T11:40:00Z","url":"https://digestai.news/story/dave-plummer-builds-custom-ram-board-for-pdp-11-using-chatgpt"},"generatedBy":"Written by Digest AI's editorial model from the linked sources; the sources are the record.","license":"Headlines, digests and key points are written by Digest AI and may be quoted with a link to the story page. Linked articles belong to their publishers. Terms: https://digestai.news/terms#reuse"}