The Naz80-A is the first of the build process and is designed to offer a simple single stand alone computer with just an LCD display and hex keyboard.

What’s NaZ80 stand for, well ‘Not another Z80’. This project has been done a hundred times and there is nothing new about it. However, I’ve not done it before, so wanted to put one together. This may also include a simple z80 compiler  – yes, not another z80 compiler. But Its fun writing a high-level language for a processor. It also gives the opportunity to make up some interesting peripherals for this.

I think the idea will be to go from something really simple to something running CP/M, VGA Monitor, Keyboard, and probably even a floppy drive – I want to keep it Retro and not have any Atmel’s or other processors doing fancy stuff – Its too easy

Versions

‘A’ – Simple computer with LCD Display, Hex keyboard and a simple monitor program to allow for basic operation.

‘B’ – Add Serial and parallel ports

‘C’ – Add composite display and PS2 keyboard

‘D’ – Implement CP/M

‘E’ – Add Floppy drive

Why the Z80? Well, like so many (older) people, it holds a special place in my heart. In the ’80s, at the age of about 9 or 10, I took on a newspaper delivery job to save up and buy the ZX81. It cost R99 (in South Africa), the same price as the UK. It was a lot of money for a 10 year old, but I did it. I can clearly remember going to the shop to buy the computer – So exciting.  I remember being on the lounge floor with the ZX81 plugged into our TV coding away. It was huge fun.

Hardware Specifications

• Z80 Processor
• 4Mhz Crystal Oscillator 
• 256 bytes ROM – Expandable to 32K
• 255 bytes RAM – Expandable to 16K
• 2 x 16 LCD Display
• Hex Keypad

Software Specifications

• Simple Monitor program 
• List memory contents
• Edit memory contents
• Run from location
• Built in routines  for LCD, keyboard and other functions

Schematic for the NaZ80-A