Shoot the engineer

A project log for One-instruction TTL Computer

A breadboard-able computer which uses only a single instruction - MOVE

Justin DavisJustin Davis 06/19/2017 at 17:431 Comment

There's an old saying that goes "In every project there comes a time to shoot the engineers and start production". Well, ya that's kinda true. We always see improvements and want to make changes. I'm thinking of making a significant change to the project to reduce my chip count and complexity. Right now I have a register for the source address and one for the destination address. And they have their own separate busses and will need their own decoding. These two sections are essentially redundant, so I'm thinking of combining these circuits into one.

The new control flow would go like this:

Now instead of three clocks per instruction, it will go to four. However, again this could be reduced if the RAM/ROM is not the source or destination. So it could still be as little as two, but requires a little more logic. But it would save at least 6 chips even if I'm adding the temporary holding register. There'd now only be one src/dst address to decode. I want to reduce my chip count as much as is reasonable while maintaining an 8-bit databus. I'll have to archive my project in case it doesn't work out.


Ed S wrote 06/20/2017 at 06:38 point

What you might do - what we did - is regard your progress as a series of prototypes. Each one informs you as to what to try next. It's not so much a project, as a program of projects. (Our progress was OPC-1, then OPC-2 which wasn't a step forward, OPC-3 which was a step sideways, OPC-4 was an idea we never did much on, OPC-5 started looking good and branched into two.

  Are you sure? yes | no