Introduction: SIMPLE Z80 Computer

About: I started out knowing nothing about electronics. Bought a Electronics Learning Lab from Radio Shack and Bam! It became my daily hobby and career path of choice. Although I am still in school I continue to try …

Hey everyone!

*** Most recent update -> I completed the main 'brain' of the system

This is my first time posting here on Instructables but I hope to do it regularly! I have always been interested in computers and I have wanted to understand them as detailed as I possibly can, so I decided to build one from scratch. I love computers, so I have already assembled full PCs, but nothing ever to this scale. Breadboarding is a hobby of mine so why not combine both!?

The product I eventually achieved was this simple z80 CPU, with RAM, some LED read outs, a Clock source and a way to alter the RAM. That's it. Completely bare bones. This project taught me tons and I have been inspired to build more complex machines, currently I am soldering a new one with RAM, ROM, and input and output ports. It will also eventually have a seven segment display.


Step 1: Second Version

This is my second version of the z80 that I am building. It is in its early stages, but I plan to program it all and run much more code on it. The last machine only ran simple memory operations. I plan to interface it with a microcontroller of some kind....most likely a arduino.

I am not putting up a guide unless there is some interest. So if you want to learn how to do this I would be glad to know!

Also, here is a great kit and resource. I have been in contact with the owner of this website and he is a great help! I suggest purchasing his kits as well, they are fun to build! I have not bought his entire computer, but I plan to at some point!

Step 2: Here's a Better Picture

For now, unless anyone here wants to know how I built this simple machine I will not put up a guide. If you want a guide feel free to ask! I will be happy too. Here is a better picture of the board I designed and soldered. This is the BAREBONES z80 (with a few extra chips). I love seeing other projects so feel free to comment with your own projects! I will continue to update as I solder my next version!

Step 3: Quick System Checkup

Tested the memory (mainly the ROM, still need to test RAM) after soldering my Chip Select logic, and it works! I need test that RAM and check that it works too

Step 4: BRAINSSS.....actually Just Brain

Well its been a while! I got stuck on one problem for a while, the Chip Select mechanism. In logic I had it down, but hand soldering leads to many errors. Anyway, after a good amount of time testing, I fixed it and ran some assembly code that sent data to the CPU, then sent data to ram, the read from ram, and sent it back to rom. It worked! That means my main "Brain" is complete, including all the major components of CPU, RAM, ROM. I still have to solder an on-board time circuit as of right now I am utilizing my arduino to time, and I will also add some debugging tools on my board assuming I have room after IO, Oh, also some pull down resistors on the data bus, but those are not super necessary at the moment. Anyway just wanted to show my progress!