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Pete's Projects: V20-MBC - Printable Version

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Pete's Projects: V20-MBC - BigPete - 03-14-2026

A few years ago I assembled a V20-MBC:

https://hackaday.io/project/170924-v20-mbc-a-v20-8088-8080-cpu-homebrew-computer

However I never managed to program the microcontroller that functions as glue logic and boot rom. While looking through my stash of components while planning a different project I stumbled upon my stash of v20 CPUs and since I never really tested them I figured now would be a good time to return to this project and finish it up.

So, a few purchases later (USB to Serial adapter, SD Card Module, AVR programmer) I now have a device that is up and running.


.jpeg   IMG_3929.jpeg (Size: 2.99 MB / Downloads: 49)

Here it is running CPM:

.png   CPM86.png (Size: 78.03 KB / Downloads: 52)

And here we are running DOS 2.1 (newer versions require DMA which this board doesn't have):


.png   DOS.png (Size: 105.72 KB / Downloads: 53)

.png   DOS2.png (Size: 98.52 KB / Downloads: 53)

Obligatory Mandelbrot Set:


.png   Mandelbrot_set.png (Size: 142.31 KB / Downloads: 53)

Pete's Projects: V20-MBC - BigPete - 03-16-2026

This is why I've been quiet for the last week or so. Now on to the next thing, I guess!

Pete's Projects: V20-MBC - BigPete - 03-16-2026

No, it can't run doom (No graphics) but text based games are playable! Examples coming eventually.

Pete's Projects: V20-MBC - BigPete - 03-16-2026


.png   trek.png (Size: 25.38 KB / Downloads: 51)

Pete's Projects: V20-MBC - Jim Rockford - 03-17-2026

BigPete, post: 2269921, member: 4840 Wrote:No, it can't run doom (No graphics) but text based games are playable! Examples coming eventually.
That has not stopped a machine from running some version of doom using ascii characters for graphics.

It will, on the other hand, probably run Adventure and Zork just fine Wink

Pete's Projects: V20-MBC - BigPete - 03-20-2026

Jim Rockford, post: 2269926, member: 28508 Wrote:That has not stopped a machine from running some version of doom using ascii characters for graphics.

It will, on the other hand, probably run Adventure and Zork just fine Wink


.png   Screenshot_20260320_135331.png (Size: 28.95 KB / Downloads: 42)


.png   hack2.png (Size: 33.21 KB / Downloads: 43)


.png   adv.png (Size: 61.33 KB / Downloads: 40)

Yeah. we gaming now!

Pete's Projects: V20-MBC - BigPete - 03-21-2026

Hack is still fun as hell for a 40 year old game

Pete's Projects: V20-MBC - Jim Rockford - 03-23-2026

BigPete, post: 2269942, member: 4840 Wrote:Hack is still fun as hell for a 40 year old game
Before I worked at more secure places, I kept a thumb drive with exes of nethack and a handful of other text games for when I would get bored.

Pete's Projects: V20-MBC - BigPete - 03-26-2026

up next is the uTerm that is designed to work with the MBC devices:

https://j4f.info/uterm

This one will be a pretty easy build with one exception:

The STM32F030F4P6 chip is a SMD IC with a Pin Pitch of 0.65mm which is the smallest work I've ever had to do. I'm half tempted to invest in a hot air rework station for this one task. Well, I'm going to try it with the iron first. I have enough of the PCBs to fuck it up a couple of times.

Pete's Projects: V20-MBC - Jim Rockford - 03-26-2026

I find that a little more than scary. I don't even think I have an iron tip small enough for that sort of work.