Working on CPU module

A project log for PDPii

PDP-11 compatible motherboard in mini-ITX form factor

SHAOSSHAOS 04/27/2018 at 06:360 Comments

1st module that I'm trying to create right now is CPU module with 1801VM2 onboard - I'm buffering everything (VM2 pins are very weak) and also this module has address decoding and indication for some important signals:

CPU might be clocked by button, by TTL oscillator or by external clock (CLCI):

Board will look like this (160x100 mm):

It could be vertically inserted into mini-ITX backplane (not yet designed), but also might be used as a standalone VM2 tester

BTW thanks to OSHPark for rendering this image ;)

Printed it on paper to see how it may fit into mini-ITX computer case:

As you can see CPU module is a little too high - power adapter will not allow to put it in most of the slots of mini-ITX backplane but if it will be the last board (as pictured above), it should be ok, because power adapter is a little bit shorter than mini-ITX board and we have some free space there on the side...