BY-product: Z80 based simple computer

A project log for Retro DIY computer project

Previously I made 4-bit CPU, and I would like to follow the progress of human being.

kodera2tkodera2t 11/30/2015 at 09:498 Comments

This is totally by-product inside 6809 project since it is working by Z80. Here you see very simple (simplest? ) Z80 system with PS/2 keyboard and monitor support. Left board contains LPC810 working as serial console, and right one AKI-80, which I bought just by 500JPY. ( Raspberry Pi Zero comparable ?? ;-)

"AKI-80" was sold by Akizuki denshi tusho in Akihabara (Japanese site), Tokyo in early 1990's. This board had some evolution from original AKI-80 (this board), AKI-80 gold (32kB SRAM) and Super AKI-80 (including RS-232C interface). They still sell Super AKI-80 by 4980JPY (including monitor ROM and C compiler for Z80) but this time I got "dead stock" of original AKI-80 just by 500JPY. They already stopped sales of non-super AKI-80 but full information (Japanese) still can be found at their site.

My board was just "board" and without any additional parts (X'tal, capacitors, auto reset IC) and I put several modifications (so not auto-reset)

This Z80 is not simple surface mount package but...

IT IS Highly integrated version of Z80 (TOSHIBA TMPZ84C015) containing Z80-SIO, PIO, CTC, and CGC just in one chip! Unfortunately this Z80 is already out-of-production but even now you can find 2nd source by Zilog at digikey. (Indeed, this is quite rare case, Zilog sells Toshiba's original product...) As a consequence of high integration, minimum computer, consisting serial I/O, can be made just with additional RAM for main memory and ROM for firmware. This time (sometimes happens to me, though), I just write EP-ROM by hex file released by great programmer (NOT ME) at ( Console is made of LPC810, this is also not my original one (information can be found at Seriously this is great masterpiece of LPC810 application!!!) and working well between PS/2 keyboard, Monitor, and AKI-80. Connection between AKI-80 and LPC810 console can be derived from this image( in this link MAX232 is connected. Instead of it, just connect with LPC810 console..) In fact, this image is a part of Japanese book and full information about this type of RETRO computer can be found by this Japanese book, written by TinyBASIC author of above link.

Actual operation can be found in the following movie.. I would thank all the original authors for releasing their great works on the web. Have fun!


Felipe E. Bennett wrote 07/16/2018 at 03:07 point

Hello, i found similar chinese  Kit in a Mexican Store, i  put link to the kit for all to check.  I already bought one. Should i get more? the price is around 30 usd. Regards

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Yann Guidon / YGDES wrote 12/01/2015 at 00:31 point

This is incredibly awesome !

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kodera2t wrote 12/01/2015 at 11:22 point

Thank you comment. Indeed it was far simpler than I've expected. Indeed, it consists of TMPZ84C015, LPC810, SRAM(64k), EPROM(128k) and one 74HC00. 5 chips enables keyboard/video Z80 system!!

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Yann Guidon / YGDES wrote 12/01/2015 at 17:00 point

If I had that in my teenage time, I would be far more advanced today :-D
I hope you release more informations about this board, or even make a dedicated "project" here, even though I'm a 6809 guy and not a Z80 guy ;-)

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kodera2t wrote 12/02/2015 at 11:38 point

OK sure. I will edit my project log with some information inclusion!

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Yann Guidon / YGDES wrote 12/02/2015 at 21:18 point

Wow ! this is even better ! a lot of great informations :-)

I'd love to do something like that with the YASEP ;-)

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kodera2t wrote 12/03/2015 at 00:06 point

Thank you comment. After following legacy technology, I want to take off to VHDL world, like YASEP... !

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Yann Guidon / YGDES wrote 12/03/2015 at 02:34 point

I'll gladly help you.

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