Tag Archives: FPGA

FPGA CPU Design — DRAFT

when I was little I was always fascinated with how things worked.  and back in the TRS-80 days it was simple and clear.  well things have progressed GREATLY since those days, and its a lot less understandable to the base user these days.  you add this nostalgia to my wishing to flex my school knowledge some in the decades since and I came up with this…

So I started building my device using a program called Logisim I’ve had some issues loading the site lately so heres the direct download on Sourceforge.  once I started progressing with that I realized its not even USABLE.  short of manually setting the logic/etc and watching the output and using an excel sheet manually its not what I wanted.    so naturally I took the big leap into something I knew very LITTLE about which has the power to do what I want (realize the actual CPU).

So as much as this is me building a CPU and yes I will demonstrate every piece for you as I do this in logisim, I will also keep the FPGA code base up on GIT with it so you can see and learn with me.

First off, I do NOT expect this to be overly useful to anyone for anything real as it’s an old school 8 bit CPU, and I expect about as much power as the old Z80.  It will be nice to at least say “I DID IT!”  but who knows, maybe one of you will take the base learning and turn it into something real world with some actual power.

Now for starters.  the base of the CPU is going to be the ALU (Arithmetic logic unit)  and in my design i’m going to start it with the basics.  lets ADD something.

Watch for the next post where we start the actual work.

a lot on my plate == no posts

Yes, I know i’ve neglected my blog for FAR too long again..  well no more.  I’ve made a schedule and I will stick to it.  new posts on many of the projects I’ve been working on to come.  every week there will be at LEAST one.

first coming up in a day or so will be about the FPGA CPU design i’m playing with.  this serves no REAL purpose other than to say look what *I* figured out.  and has already elicited assistance from a fellow blogger.  Alex from http://langster1980.blogspot.ca was a great help in sorting out my Component embedding whoas.

Then there’s the Coleco Video output fix, 2 AVR projects and a Microchip as well as countless 3D printing updates. so stay tuned!

Where have I been

Well that didnt go so well. Life, Kids, Sports/etc… things get in the way.  but lets fix that now.  I have been playing around with a Mimas V2 for a short while trying to learn FPGA and i’m doing well I think.  Recently I decided to try and learn how to drive the VGA.  although far from a proper working solution I can get the driver to work on my multisync monitor.  I have reached out to a fellow FPGA/Mimas V2 blogger (Alexander Lang) and he’s agreed to help me figure things out.  of course I’m always interested in information/assistance from my readers as well so heres the GIT.

https://github.com/duckyvirus/MIMAS_V2_VGA

Pics, etc will be available soon, unfortunatelly posting this from the office right now.  I also promise to try and get back into the weekly postings again and I’ll share more on my projects (I have several on my bench right now).

as always stay well and don’t forget your towel!

— James