Episode: 3993
Title: HPR3993: z80 membership card
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr3993/hpr3993.mp3
Transcribed: 2025-10-25 18:24:14

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This is Hacker Public Radio Episode 3993 for Wednesday, the 22nd of November 2023.
Today's show is entitled, said 18 Membership Card.
It is part of the series Hobby Electronics.
It is hosted by Brian Inohio and is about 16 minutes long.
It carries a clean flag.
The summary is a review of a kit.
Hello Hacker Public Radio, Brian Inohio here.
I'm up from under my rock and I'm recording another show.
This connected to the project of the Homebrew Z80 project, the last couple of episodes
that I did or about, and looking around YouTube and such to get ideas, I found an interesting
computer called the Cosmic Elf, which is based on a different chip than the Z80, RCA 1802.
And then looking around, as you do on the YouTube, going on the YouTube rabbit hole, I came
across a website, SunriseEV.com, Sunrise-eV.com, and it's a links are in the show notes.
It's a website of a gentleman Lee Hart, from the front page to find out he's an electrical
engineer.
He says that he was there at the beginning of the computer revolution and it has a lifelong
love of electric vehicles.
So his website is broken into three parts, actually.
One is for EVs, which we're not going to talk about today, and one's about old-style
computers, which we are going to talk about today.
And also there's some of his writings, which are actually quite funny, some of it.
So anyway, when you look through his website, you'll see that he offers a number of kits.
The kits range are all retro computer kits, and they use old-style components, no new
stuff in it.
And one of the original things that got me to his website was a cosmic elf that's built
into an Alttoids can.
It's really cool.
It's an Alttoids tin, which if you don't know what Alttoids are, they're a little...
They're a curiously strong mint in the little metal box, and I don't know, I think 10,
12 years ago it was a big deal to put stuff in them, and it is kind of cool.
But there's the cosmic elf with the big toggle switches in front to programming, and then
if you look around, you'll see that he has what he calls the C80 membership card.
The C80 membership card is what I ended up buying from him, and you can buy just blank
boards.
There's schematics that are available, and you could horse horse the parts yourself
or you could buy the C80, the full blown kit, which is what I did, which is the C80 membership
card, which is the main CPU board, and the front panel, which allows you to program the
little computer right in the palm of your hands.
So that's the kit that I bought.
I'll just say first off that this is a work of art, the ability to design a computer,
put it in and make it into a form that would fit inside an Alttoids can and actually functions,
and it's actually a very usable computer, it is quite amazing.
My hat's off to Lee Hart and what he's designed, but it goes beyond that.
The documentation is tremendous.
It comes with, and I've got a picture in the show notes, as I thought it was worth showing,
but it comes with the main instruction manual, has this cool, full color throwback to
like a mad magazine kind of front page, and I guess it's actually, it says here, it's
inspired by creative computing, 1979, and that in it is sort of a tale of how these two
guys talking back and forth like on a bulletin board and designing a computer, and then
in the end you end up with the documentation on how to assemble this work of art.
The documentation is just excellent, it's the instructions of throw and easily to follow
if you're a slightly above a novice soldering person, I'm sure you can build one of these
kits if you just take your time and read what's there, but that's not all.
In addition to it, you get a note from Gil Bates himself, the emperor of marketing at
itibiting micro company, and it talks about the computer, that's like the user manual
for the Z-A-D membership card, and it's printed out on this old school wide form printer
paper with the holes on the side, the feed paper, and it's got, it's all printed out in,
and it's an ASCII art, and it's a very nice brief, but very thorough introduction on
how to use the membership card, either via the front panel, or by hooking up a serial
cable and using a computer and a terminal, you know, PCNN, and a terminal emulator, terminal
programs, a Terra-Term or, if you're on a Windows box or putty or, or just e-max like I would
use.
So you get the kit, the kit's $80, so it might be too much for some people, but I had some
allowance saved up, and I decided to buy it, and it comes, everything comes in a small,
you know, in an envelope, and you get all the components are inside the little alt towards
the kid that you get, and so the, go to my pictures here, because I will, the pictures
are in the show notes, and I'll just sort of quickly, quickly narrate what's on the pictures
if you're not going to look.
So the first picture is the actual picture, is the assembled membership card.
That's the Z80 processor, the RAM, the E-Prom, some glue logic chips, so the regulator
for power, and that board by itself is a functioning Z80 computer.
You can hook a serial connector to one of those FTDI cables you can find on Amazon, and
you can start programming the computer just with that part.
The second picture is the backside shows some of my tremendous soldering skills, and
you'll also see that there's some unique use of the headers, those pin headers.
He describes how to do it, and if you follow his instructions, that's what makes the
whole form factor squashy enough to fit inside that alt towards 10.
The next picture is the front panel, and that's the interface board that you can then,
you can just use this to program the Z80.
It has a, E-Prom has a monitor program, monitors a very low level program that allows you
to examine memory cells, and insert memory, and modify memory, and so basically do programming.
This keyboard has, it's pretty amazing, it's got some LED and some feedback, so we press
buttons at beeps, and that's what that big golden disk in the center is.
And you can, and I have, you can, you can just go ahead and program your heart's content
right there, just one byte at a time programming, which I'll describe here in a second.
The next picture just shows the backside of that front panel board, and it's got some
of these white connectors, which I've never seen before, but they're, you have to cut them
up a little bit to make it all work, but it's, it's pretty easy, like I said, the instructions
are excellent.
And then the next picture shows how they're sandwiched together, and you can already see
how it'll fit right into a little alt towards can.
And there it is, the next, the next picture shows the, the whole computer inside the
alt towards 10.
I lined my alt towards 10 with some electrical tape, just for, so we'll short out anything
we'll short out.
And then I also made, I had this little battery pack for years, this, that's the next picture.
And it has this built in USB cable.
And so I made a little USB adapter board, and I'm able to, and there's, I have a picture
of the alt towards 10, just in case you don't know what that is.
And then the, there's, there's another picture that shows the computer sitting on top of
that battery box with those USB adapter plugged in.
That's, you're just for power, that's just to power the, the, the little computer.
And then I put, put a cheat sheet inside the front cover, that shows the functions of
the keys and some, what the little LEDs mean at the top, just to help out, once you get
going, you sort of quickly figure out where, where keys are and what they mean.
But it's helpful.
And then there's the last picture is the picture of the documentation, all, all very cool.
So in the end, the, easy to assemble, I thought, just take your time, read the instructions.
The board is beautiful, the solder mask is awesome.
Even though it's a tight fit, it's, it was easy to solder it and get any solder bridge.
It's all through holy components, so there's no SMD, soldering, no real tiny stuff.
So it's, if you're looking to, for a soldering project, the next step up, maybe this could
be something for you, something that's actually a little bit funner than, funner, a little
bit more fun than, than merely blinking lights or something like that, a, a, a, a, a, a
useful computer.
Um, there, uh, I talked about how I added some things, the battery pack and that, and then
it all bell-crows together.
So I can just hold it in my hand and, with that front panel, I can happily, uh, put in
machine code and make the little computer, uh, do stuff.
So, um, so that, I guess I should talk about its usage, uh, it's really a great little
board to, to learn Z80 assembly code.
And so, assembly code, I'm not gonna, if you don't know what assembly code is, go to Wikipedia,
but basically what you're doing is, for, what I've been doing is hand assembling programs.
I write them down, real small routines, decrements, stuff, move a, a bite of, uh, move, uh, some
information from one register into another, uh, 16-bit addition, 16-bit subtraction.
Small routines, they're maybe, you know, 15, 20 lines, something very small because you
have to punch in everything, uh, number by number, so you don't want it to be too long.
But a lot of, so I, I write what I want to do down, I've got a book, a couple of books
with some, uh, tutorials, and then, so I follow their, their tutorials, and then I, uh, hand
assemble it, so I take the monomic, and I find the number, and I convert the numbers,
and I, and I've got a systematic way of writing it out on a piece of paper, and you end up
with a, uh, sheet of numbers, and then you just, one by one, enter those numbers from the
front panel, and then you can go back and look to make sure you make any mistakes, and
you can fix things if you do, and then you can run the program, and, uh, see some output,
hopefully.
And, and so I don't think this is long term is the way to go with, uh, with any computer,
but it certainly is a way to learn the rudimentary or the, or the, the foundations of assembly
language program, um, in a fun way. And then the next step with this computer, if you're
to go on is to hook it up to a, uh, uh, regular PC via that serial terminal, and then you can
use the monitor, and then it's, then you have the keyboard available, and it's much easier
to do stuff, and then you can, there's assemblers available for, um, the Z80, uh, that are open
source, and you can, to then, uh, rights of assembly code have the, assembler, uh, assemble
the, the program, and then spit out a, uh, uh, file, which you did could upload with your, uh,
serial terminal. And then if that's not enough, you can buy another board that he offers. It's, uh,
it's a little bit more. It's like another $50, but with that board, you get 120 K of RAM. You get, uh,
a proper, uh, your art chip and some input output chips. That's a Z80, um, it's something that
Xilog built, uh, to, as part of the whole Z80 family of chips. And, uh, with that, you can run
CPM. And if you don't know what CPM is, it's basically the, it's a very early operating system.
It's a single, single person operating system, not multi-user like, like Linux. And it's, uh,
but it allows you to access files, move files, save things to disk, things like that. And it's, uh,
that little board allows you to run CPM, which is, uh, it's like DOS if you're a Windows person.
I guess you could, uh, we could understand that. Uh, and then at that point, you've got,
there's all kinds of software out there. There's financial software. There's lots of games. There's,
um, uh, Zork, I guess, was probably think first was on the CPM. So anyway, it's,
there's all kinds of good stuff for that. So the, the computer is, is, um, uh, even expandable,
just from beyond the kit that I bought, which is very cool. So my takeaway from this, uh, is that,
Lee Hart is a genius. He makes, uh, and this kit is excellent kit. The, the creativity in it,
the, you know, it's not just, uh, an A4 sheet of paper with some instructions. He went,
he actually did some creative thought on how to do documentation, which is wonderful. And the
documentation itself is just amazing. And then, um, uh, it's, uh, well within the reach of a,
of a novice soldering person to, to put together, he has, if you're not a Z80 person,
if you want to do 65 by two, if you want to do cosmic elf, there, he's got all the stuff right
there on his website. Very, very, very, uh, nice stuff that's there. Um, I think if you're looking
for a gift for somebody who's maybe a kid who wants to learn to solder or is soldering, but what's
something, another, another thing that challenged to put together and have a, a functioning computer,
that's kind of, be kind of cool. If you, um, uh, or if you're going to buy a gift for yourself,
something to do, I just, I cannot say enough about the quality and the, the, the workmanship of
this piece of art, this little computer that, that, uh, reminds us of the bygone errors when,
when computers were, uh, much more understandable and probably led to more creative,
creativity and less destructiveness that the current internet provides. So with that,
it's, uh, I'm Brian and Ohio. I'm signing off. And, uh, I guess I'd like to remind everybody to
pick up a mic and record a show for yourself, keep the project going. Bye-bye.
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