Using the TD8-E with the MS8-C memories

[Bob Armstrong]

>Eric wrote:

> However, some PDP-8/a configurations used the later revision of the
>M8300/M8310/M8330-YA CPU along with semiconductor memory (usually
>MS8-C or MS8-D).  In this case, the engineering designation of the CPU is
>KK8-F, to distinguish it from a KK8-E which might not have the necessary
>stall support.

  AFAIK the only requirement for using a KK8-E in the 8/A chassis is that
the M8320 timing generator board has to include a certain ECO.  This is
spelled out in the "PDP-8/A Operator's Handbook", p3-3.  The rest of the 8/E
board set is the same either way, and the modified M8320 still works in an
8/E chassis.  I assume that at some point all the M8320s produced had this
ECO and thus would work either way.  This is the first I've heard about them
having a special designation.

  The manual doesn't say specifically what the TG module ECO does, but it
wouldn't surprise me at all if it had something to do with implementing NTS
STALL.  In any case the change can't have been too complicated since it
could be done in the field as an ECO.

Bob