Z80 retro-computer - the size of your wallet (if you have a fat wallet)

I short while ago, I teased that I was going to do some time-travelling back to the 1970/80s....

I did actually purchase a Z80 MBC3 device, getting around the Brexit problem of not being able to purchase items from The Netherlands because of the massive VAt charge for importing the goods into the UK - yeah, great, thanks populace dim-witted knuckle-scraping thug heads for that decision - anyway, way arond it was for the seller to pay a small fortune themselves in fee's / costs and also for me and to get the item via eBay too.... yep, of course there is a loop-hole. don't expect it to stay open for too long though.

More info at github and a new WEBSITE to purchase the kits from

I received the board and all the parts and was ready to do a soldering session and then a really odd thing happened in the UK - the sun came out...for more than 1 day. This meant I had to switch from doing things "in the house" and go and do all those "other things" that involve being outside, like gardening, cleaning of motorhome roofs, etc..etc... so the electronics would have to wait.

Well, thanks to a nice chap called Derek Cooper, who saved me doing some soldering work by selling off a few of his spare devices that he'd already put together - I now have TWO Z80 devices :-)

This one is an RC2014 based device that is nice and modular in design with plug-in and out boards, a bit like the ones you see in the movie 2001, that Dave is seen yanking out of HAL whilst the AI is singing Daisy Daisy.... I received this device, very well packaged! and I proceeded to plug in the MASSIVE 128MB (yes, that is MEGA-BYTEs) CF Card and then plugged it into my laptop (an UBuntu linux distro. of course)

Well, as the device uses a FTDI to USB converter (basically converts SERIAL to USB Tx/Rx to send data back and forth to the host computer), I plugged it in and a new /dev/ttyUSB0 appeared, great news, a quick $lsusb shows the device is detected, just need to open a terminal session to the device.

There are a few options available to do this as shown here, simplest is using 'minicom'

$minicom -s

went into settings for port, changed A to be /dev/ttyUSB0 <pressed ENTER> then ESC and then Exit.

and sat there a t a flashing prompt...I pressed keys, I fiddled with things, I pressed the reset button on the RC2014... nothing. I sighed. did something get broken in transit? I noticed the main board has an LED lit but the CF Card one has an LED but it is not lit... did stuff become unseated?

I then started again, ah ha! It LIVES!

So, it has detected the following DEVICES:

Which is correct.

Looking at the text from the image above, I see that I actually have to TYPE commands to get the Z80 to boot into anything. So if I want to boot into CP/M, I actually have to type CPM

If I want it to boot into BASIC (like the good old days), I have to type BASIC

I actually did wonder how it was going to "detect" what I wanted to do. I guess we're doing it the old fashioned way :-)

BASIC it is then:

(I did wonder, as muscle memory put that semi-colon on the end - it's there, if you remember, to make the text print after itself rather than onto the next line - I now need to RUN this to see if it errors or does what my brain remembers!)

Ha!Ha!Ha! okay, so because it is running in a Terminal window session, it doesn't behave as I expected - it does attempt to do it though, the text just goes off the screen on the same line and you have to ctrl+C to break out of it. Ah, I guess running it without will have to suffice for now. anyway, proves that BASIC works fine.

Now, a [reset] and type CPM and see what we have there.

Yep, thanks to Derek for setting up the CF Card for me previously), I should really go back it up just in case, as you can see CP/M boots up and works a treat!

There are 16 partitions available, ZORK appears to be on drive C, but on drive D, oh look there is a C compiler!

Muwahahahhaaaaa! Okay, so this is kinda fun. oh apparently I am [user0] and if I become [user1] then I can see different content, there will be TURBO PASCAL instead of C. I need to figure out how to change user to be able to see that.

So, what's the big hu-ha with this? Well, I never used CP/M back in the day, it was just a little bit before my time, I was kind of aware of it, but I arrived at the Microsoft DOS stage in time - and due to their marketing and dominance, they basically took over from CP/M and became the defacto-standard; regardless of whether MS-DOS was actually better or not. As I grew up with MS-DOS 3 / 5 / 6, it is kind of interesting to "see what was there before" and to realise just how good and powerful it was / is and potentially what I can now use it for in its limited fashion.

There are several little projects that I want to do that don't need a Raspberry Pi, a PICO, or an Arduino as they are "too much", however, I could use the humble Z80 to do the task instead.

....

and of course, I couldn't just leave it at that - the blades are modular after all! Yes, the board that I purchased was on a fixed 3-board backplane, so cannot be extended further, however, I found THIS GREAT SITE, that then just sold me a 5-slot version and I may or may not have also purchased the Pico VGA output board too (yes, there is a sense of irony there using the massive power of the Pico to just be a graphics card output!), then I just may look into getting the Input/Output board(s) too... and see what I can then do with them....

https://z80kits.com/shop/rc2014-pi-pico-vga-terminal/

https://rc2014.co.uk/modules/pi-pico-vga-terminal/

[UPDATE: the VGA, Backplane 5-slot and a few other items arrived in the post today! I'll solder them up next week]

Right....well, now I have that up and running. I may come back to soldering the MBC3 this weekend, oh hang on, I just remembered the BEAST is at a car-show this weekend, maybe I should give it a little clean and then go sit in a field all day to show it off to other people, it's a shame I can't take a table and soldering iron and built the MBC3 device there.... or maybe I can?!