Grundy NewBrain: Part 8a (Internal SRAM Store Board)
13Working on creating a replacement internal store board for the Grundy NewBrain to replace the existing 32KB of DRAM with a single SRAM.
The original design uses two banks of 16k x 1bit DRAM and so has two separate row address selection signals (RAS16 & RAS32) plus the column address selection signal.
We need to demultiplex these so they present at the same time to all the SRAM address lines.
Part of this requires figuring out how to re-use or re-design the original RAS signal creation. I thought that it might make for a mildly interesting video.
Once again - I don't profess to be an expert in either Kicad or digital electronic design - but by getting my hands dirty I am learning little by little.
By all means you are welcome to point out the flaws in my naïve assumptions ... thanks!
My work on this project can be found on Github - as of now (4-Sept-2023) I have not finished nor tested this design:
https://github.com/0ddjob/Grundy_NewBrain