Flash Programmer

A project log for Z80 Computer

An attempt to build a Z80 computer capable of running CP/M

techavtechav 05/03/2015 at 07:320 Comments

I've been working through the code for reading/writing/erasing my flash chips. I've got reading down and outputting hex format nicely. Chip erase is working, but sector erase still needs some work. For writing, I've been working on the code separately, and have it correctly parsing hex format; I just need to roll it in to the rest of my code. I'm getting to the point where the code is unmanageable in the Arduino environment though. I need to get a programmer and start using a real IDE.

I spent the last two weeks obsessively checking the USPS tracking site hoping for any update on the parts I ordered from China to come in, and finally today they were delivered. I got some 40-pin ZIF sockets, pin headers, a Mega shield protoboard, and after a few hours soldering, I have an Arduino Mega Flash Programmer Shield. Not my prettiest soldering job, but it works. I am a little annoyed with myself for a careless wiring mistake—my control lines I ran around the board to Analog 2-4, when I meant to run them to Digital 2-4, which would have been a short, straight shot. Oh well, it works either way.

Hopefully once this semester has wrapped up I'll be able to finish the programmer and get some code burned, so I can start testing the Z80. I think I've got my initial schematic figured out, but need to order more buffer/drivers and maybe a few other odds and ends logic. I want to try to build the glue logic out of 7400-series, but if budget doesn't allow, I'll use the Altera CPLD I already have.

I also picked up a used copy of "Microcomputers and Microprocessors" at Half Price Books. It goes through interfacing and programming the Z80, 8080, and 8085. It has already proved very helpful for a few points I was fuzzy on.