dumping Western Digital Microms (PDP-11, WD16, Pascal Microengine)

[Eric Smith]

On Mon, Dec 21, 2015 at 9:48 AM, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
> I was going to point out that there is another uROM (KEV11) for the LSI-11,
> for the EIS/FIS, and also that there is some variation in the numbers of
> the uROM chips, but along the way, I ran into a puzzle.

> - 2007C 23-003C4, 3010D 23-008B5, 3007D 23-007B5

The 23-007B5 and 23-008B5 apparently are multiple Microm variants for
the base instruction set. GIven that the WD numbers are still 3007D and
3010D, I'd expect these to be only packaging or minor electrical variants,
but it would still be nice to read a set for verification.

There are also two part numbers for hybrid Microms, with two Microms
packaged on one DIP carrier, DEC P/N 23-002B6 or 23-003B6.


> ii) the 'Control' chip must also be a uROM, and that
> there is some variation in how the 3 chips can be plugged in?

The control chip and data chip are not Microms, and MUST be plugged into
the correct socket.

The Microms all have the same pinout, and are wired completely in parallel,
so they can be interchanged.

In addition to the normal

> Getting back to the KEV11, the one I have seen is a 3015 23-003B5.

There are a number of variants. That is a KEV11-A EIS/FIS, suitable for
the M7270 quad module etch revisions E and F, and the M7264 dual.

Another version of the KEV11-A EIS/FIS, suitable for the M7270 quad
module etch revisions C and D, is the 23-091A5. I don't know the WD
part number.

The KEV11-B provides EIS without FIS, suitable for the M7270 quad
module etch revisions C and D, 23-090A5. I don't know the WD part
number.

The KEV11-C provides a subset of the CIS commercial instruction set,
sometimes known as DIS (DIBOL instruction set), using two Microms,
which are 23-004B5 and 23-005B5. I don't know the WD part numbers.
I suspect there is probably also a hybrid (single DIP carrier) version of
the KEV11-C, but I don't know the part number.