Showing posts from April, 2015

User Interface Design: Instruction, Clock and Sequencer

Over my last seven posts I've been slowly putting together the card designs so that the computer will be able to operate the MOV-8, ALU and SETAB instructions. The final step in this series is to update the designs for the two display cards along with the main switches to work with the new cards added recently.

Diving straight in here is the latest version of the Display A design:
This is the card that sits in the upper left of the enclosure and doubles up as a display as well as a means of directly operating some of the control lines. Each block on the diagram is an illuminated tactile switch that directly displays and operates an individual control line. I've faded out all of the existing switches so that the new ones are highlighted.

The two new yellow switches in the middle drive the Load Instruction Register and Load Condition Register lines. Previously I'd temporarily wired up the 'Sel AS' switch up to the load condition register line but now it'll have i…

Control Design: MOV-8, ALU and SETAB (part 2 of 2)

In part one of this two part post I introduced the design of the control relays for each of the MOV-8, ALU and SETAB instructions. With these in hand I can now move on to placing these on the control cards and wire everything together. That's 'cards' rather than 'card' as the control relays will be spread over two cards just like the sequencer relays are. This is partly because there's more relays than would fit on a single card but mainly because access to a wider range of busses is needed.

Getting stuck in, here is all the relays laid out across the two new control cards:
On the left hand card there is the CHAT relay floating at the top right then down from there are the three SETAB relays and below that the five ALU relays. On the right hand card there is the eight MOV-8 relays. As with the sequencer card there will be more relays added to these cards as further instructions are added.

Adding in the wiring posts, internal links and diodes gives the followin…