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About the Olduino/Z

The Olduino is a retro-Arduino.  This one uses a Zilog Z80 processor from the 1970s but adds hardware and software so it can function  like an arduino and use some arduino add-on shields.  The Olduino/Z is more limited than an Arduino but that is part of the fun.  The Olduino/Z has 8 dedicated output pins and 7 inputs one each of which is dedicated to serial I/O.  It lacks(so far) analog input and output capability but can still use many basic shields.  The Olduino has hardware support for high speed SPI(Serial Peripheral  Interface) through a TP3465V interface chip on the olduino board.  It does bit-bang serial communications to an attached PC at 9600 baud courtesy of a monitor program in the onboard ROM.  Programs in C using arduino-type constructs like digitalWrite() and millis() are written on a host PC using the Z88dk compiler setup and loaded into non-volatile ram by an xmodem bootloader.

16-03-29 aboutimage

The Olduino is based on Lee Hart’s Z80 Membership Card computer   (manual with schematic) and the Z88dk Z80 development kit with the  Small Device C compiler(SDCC).

There’s a nascent interest group for the Z80 Membership Card at

14-08-27 billtoo

My name is Bill Rowe. I built my first home computer in the 1970’s from the Popular Electronics article. I got out of hardware hacking in the 1980’s but came back when somebody gave me an Arduino in 2008. When Lee Hart made the little Membership Card I thought “Hmmm Olduino?” The Olduino has been through several generations of hardware and software and boasts its own C compiler. I have enough development plans to keep the project going for a while.  You can reach me through the form below or directly as bill_rowe_ottawa at

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