For those who are a tiny bit familiar with me, I've been interested in microprocessor architectures way before I learned to write software. That's about 15 years ago now. Sometimes, lately, I question myself as to why I haven't just bought old CPU components earlier.

As you may or may not know, these architectural designs are over 50 years old about now. They remain a classic. But, the components are quite difficult to find in Europe. I did manage to find a retro-style webshop which I purchased used or NOS components from!

Part list

I couldn't find all WDC CMOS versions of the 65-family of ICs, so I went with a peculiar combination:

• W65C02S (CMOS, 14 MHz)
• MOS 6522 (NMOS, 1 MHz) 'VIA'
• R6551 (NMOS, 2 MHz) 'ACIA'
• W27C020 (256 KiB) EEPROM
• AS6C62256 (32 KiB) SRAM
• SN74LS00N NANDs

Given that I have a 1 MHz crystal oscillator, this runs fine. I'm using an LM7805 fixed 5V voltage regulator to power this through a 9V battery. There's a slight but acceptable voltage drop throughout the circuit.