Using the TD8-E with the MS8-C memories

Chuck wrote: It's the signal that slow memories use to stall the processor if the memory cycle will take longer to complete than the processor timing normally allows, either because the memory is slow or (for semiconductor memory) it is performig a refresh cycle. The stall signal wasn't originally part of the Omnibus definitision because it wasn't necessary with MM8-E or MM8-EJ core memory. The KK8-E CPU didn't support it until late revisions of the M8330 module. The PDP-8/a most commonly uses KK8-A CPU, which is a single hex module (M8315) that runs slower than a KK8-E and doesn't support the optional EAE. 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. Eric