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Initialisation vector - Early Designs

A project log for z80 Experimentation Kit

A project to produce a kit for experimenting with z80 CPUs - More an embedded board than a PC

michael-cullenMichael Cullen 01/02/2018 at 13:520 Comments

I’ve been researching and playing around with schematics for a few days now and I think I’m getting somewhere. A non-exhaustive list of what I have is:

External Programming

One of the things I’d like to have in this design is an easy way to program the EEPROM within the circuit to create something more self contained. Currently I have an ATmega 8515 in the design - mainly because it’s the cheapest AVR on RS with enough pins to do this. It sits on the address and data busses so it should be possible to have it read and write the SRAM as well. Unfortunately it can’t use the IO components because there weren’t enough pins on the microcontroller for the IO toggle line. I have an idea though that might allow it access to more pins - or maybe even allow using a smaller microcontroller. The only issue is it requires some extra ICs and the part count is getting quite high!

Next Steps

In no particular order, the next steps are:

Other thoughts

Right now there are a few things that need more thought:

Discussions