Z80 Mem­ber­ship Card

I love the Z80, I started my career writing Z80 assembly for various embedded projects on a Z80 host system 45 years ago.

But you don't need a physical Z80 to enjoy that classic instruction set. For example see this source file from one of my projects; https://github.com/billforsternz/zargon/blob/main/src/zargon...

The good ole' Z80 assembly code is right there unaltered on the right, but it executes using C macros. In my humble consumer laptop I get a 40,000 times performance boost compared relative to a colleague's physical Z80 running the same code. I love the combination of nostalgia AND modern hardware performance.

I grew up in a world where the Arduino already existed, but it was not until I tried building homebrew Z80 computers like this that I really felt I understood how computers/processors work at the low level.

Consider this a warning though: this hobby has caused me to involuntarily collect every model of Z80 powered TRS-80 computer.

If you wish to become hooked anyway, this project might be another good place to start: https://hackaday.io/project/159973-z80-mbc2-a-4-ics-homebrew...

Here's some context on the RCA 1802 (COSMAC) Membership Card, also by Lee Hart at the same website, which is the real star of the lineup:

http://www.retrotechnology.com/memship/memship.html

There's also an 1802 Membership Card—which I knew as the COSMAC Elf Membership Card [1][2]. Switches and LEDs. I built one of these kits a decade ago but mine didn't work. (I still need to pull it out and try to debug it. For all I know I did assemble it correctly and there is just a RUN switch or something I did not know to flip.)

[1] http://www.sunrise-ev.com/1802.htm

[2] http://www.cosmacelf.com/gallery/membership-cards/

Love the Freak Brothers references; two US counter cultures that do cross pollinate. Z80MC RAM & ROM seem v generous compared to the ZX81 I used to cut my asm teeth, wobbly RAM pack and all...

Nice to see old tech revitalised - I had fun with the Australian version of a Z80 single board computer - https://en.wikipedia.org/wiki/TEC-1

It's a shame Zilog stopped making Z80s. Presumably this means you can't make one of these from new components any more. Perhaps someone could create a new iteration of the same idea.

Very cool. My version of this years back was a TI-83+ I learned asm on.

I think this is very cool, even though I have no historical connection to the Z80 it's of course a well-regarded and firmly entrenched/popular retro CPU.

But this really is a stretch:

The Z80 Membership Card itself is a stand-alone single-board computer that can "power up" your projects, like the Parallax BASIC Stamps or Arduino microcomputers.

Both of those are very commonly called microcontrollers, not microcomputers, since they have all of those extra chips merged into the single package of the CPU.

Take a look at the Arduino Uno [1] which is a very typical (if old) example: you will see that the board is not covered in ICs from edge to edge, since all of the main functionality is in the single-chip microcontroller. I think the second big-ish package visible is for the USB, but that also disappears on more modern controllers with on-board support for USB.

[1]: https://en.wikipedia.org/wiki/Arduino_Uno#/media/File:Arduin...

This is pretty eye-opening. It really drives home how simple the core control logic can be. Starting with toy cars or small-scale vehicles feels like a great way to teach and validate these ideas before layering on unnecessary complexity.

fwiw, I have two Z80s--maybe more--in a box among all my other parts.