<![CDATA[Just saw a tantalizing image of the 80c286 microcode ROM, via @sqpat]]>Just saw a tantalizing image of the 80c286 microcode ROM, via @sqpat

It's not an implant ROM like we found on the NMOS 286. That's surprising, since it means the ROM mask was redone for the 80c286, something that I assumed was unlikely after talking to a few folks.

The image is not quite clear enough to attempt a bit extraction. But it means that it's possible.

]]>https://forum.fedi.dk/topic/79fa06d6-c7a8-47a3-8fe7-b15dfd99f4d0/just-saw-a-tantalizing-image-of-the-80c286-microcode-rom-via-@sqpatRSS for NodeSun, 11 Oct 2026 10:53:09 GMTFri, 25 Sep 2026 03:49:03 GMT60<![CDATA[Reply to Just saw a tantalizing image of the 80c286 microcode ROM, via @sqpat on Fri, 25 Sep 2026 03:56:08 GMT]]>@sqpat

It's tantalizing because you can essentially see the bits. The column-selection circuitry is at the top, the row multiplexers and ROM output lines on the right.

]]>https://forum.fedi.dk/post/https://oldbytes.space/users/gloriouscow/statuses/117329662371000416https://forum.fedi.dk/post/https://oldbytes.space/users/gloriouscow/statuses/117329662371000416Fri, 25 Sep 2026 03:56:08 GMT