PDP-11/03, LSI-11 KEV11-C CIS option

Eric Smith spacewar at gmail.com
Sat Jan 30 14:29:32 CST 2016

Does anyone have a PDP-11/03 or LSI-11 with the KEV11-C CIS
(Commercial Instruction Set) option? It may have also been known as
DIS (Dibol Instruction Set).  It apparently consists of two microcode
ROM chips (MICROMs), 23-004B5 and 23-005B5.

Last month I posted here about building a circuit to dump the contents
I've dumped the base LSI-11 instruction set chips and the EIS/FIS
chip.  I've partially disassembled the former:
and verified that the latter matches the EIS/FIS microcode source code
provided with the KUV11 writable control store support software. I'd
like to dump the CIS microcode ROMs as well. The resulting dump would
be usable by anyone with a KUV11. I'm contemplating developing a
MICROM replacement board, which would be useful for those without a

I've made more progress with the WD9000 Pascal Microengine microcode
than the LSI-11 microcode because someone provided a photomicrograph
of the CP2161 control chip and I was able to dump the PLAs. I should
be getting a photomicrograph of the CP1621 control chip of the LSI-11
soon, and will be able to do the same for it.

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