Altaids 8085

[syzygy]

For some reason, I had an interest in playing with an 8085. Nothing too serious, just enough to capture the flavor of those past days. I was looking for a minimal system and some minimal effort, because this was strictly for S & G.

I looked into a minimax8085 and an altaids8085. Both looked interesting and I went with the latter. Here, I thought I would share my first impressions in case anyone else is interested.

I bought a bare-board, which was a pleasure to fill. Everything is through hole and the silk screening makes it all so easy.



I had to get some parts but I also had some parts. Everything went well.


I used an FTDI USB-serial board and a separate power supply. As per the article and examples, I used TeraTerm to communicate; which I was already familiar with.

Powering up was an "oh yeah!" moment.


As you can see, there is a nice little collection of software included (I burned the .hex from the zip file, into the eprom).

So, at this point, I figured I needed to flash an LED and I needed to write some kind of a Tiny Basic program - the author wrote a variant of Palo Alto Tiny Basic.

I don't know if I have ever written a program in any version of any Tiny Basic, so I was just trying to get something...anything. In a little bit, I had a "guess the number" game.


You can save and retrieve your programs (XMODEM). You can also just send the file and watch the 2400 Baud keypresses which is entertaining - for a bit.

I did manage to flash an LED, but I really need a simple latch like an ls175 (e.g, the article example) and I couldn't find one in my boxes, but I managed to kludge something together using an ls373 that worked, more or less. The schematic shows clearly how he decodes a WR signal (there are two ports decoded (I/O) and 9 pins taken out on the board.

So, all in all, I think that it is pretty nifty piece of work and a relatively inexpensive way of playing with an 8085. I can foresee a few weekend projects with this little board in my future. If you are interested, by all means, check it out.

 

[gcmurray]

Our local university homebrew club just did the Altaids 8085 as a group project. Did a build party and got (mostly) done before the end of the day. Then we did a little presentation on burning EPROMS and using the FTDI board to interface with it, use a program like gnu screen to connect and after pressing reset, voila, there's the monitor! I at first couldn't figure out how Tiny BASIC uses strings, but then I noticed some documentation inside the rom asm file that talked about the memory layout for Tiny BASIC which says that there's an @ array, and that it overlaps (going downwards in memory) with the other array space, and then I put that with the fact that there's the PUT$ and GET$ command to figure out how to work with strings. I was attempting to DIM A$(5) for a small string and it did not recognize the $. If anyone has a reference to this particular version (Palo "Altaids" Tiny Basic) that would be great. Granted, it's more-less as the other ones, but it would be nice to have a specific reference. Here's my little SBC in a can:



I would like to try to interface with my dumb terminal and also maybe connect it to a LoRA module to communicate.

 

[syzygy]

@gcmurray Welcome to the site. I was surprised to learn that you had a university class that used that board, but pleasantly surprised. I am curious, what is the name of the class? EDIT: Reading a little more carefully, I see that the project was part of a computer club activity rather than a course...still pretty cool - I like the idea of a 'group build"

There are several versions of Palo Alto BASIC and you can find much on them, e.g., here and here. Also, check out the biographical information on the author Li-Cheng Wang.

 

[gcmurray]

Yes, it was good fun and it really did help everyone avoid mistakes and get things right the first time (some of us had never seen a tantalum capacitor before!) I will take a look at these resources, I appreciate it @syzygy !