KenF wrote:Anybody else on here that makes their own cards? Either by sending a KiCad file to a fab shop, or from scratch? I actually got into the PCB hobby somewhat before restarting my interest in 8 bit computers - sometime in the early 90's. As my interest in 808x/Z80s is to use them, rather than collect and restore, a specific need for the bus is not satisfied by going to Amazon and viewing their vast offers of S-100 cards.
Nowadays the process is fairly inexpensive, although requiring a considerable amount of space and LOTS of water, but really good, if not totally professional-fablab quality, cards can be made. I see a considerable number of builders that design circuits and micros, but all send them out to be actually made. (
https://www.retrobrewcomputers.org/doku.php?id=start) Probably doesn't cost that much, but has to take a week or two or more before something comes back. I can make an S-100 (or S-44, S-86, etc) card in about an hour, not including soldering components. (And definitely not including KiCad time, which can be an hour or a month.)
Just curious. Haven't yet found anyone who does the whole raw process.
Ken
I guess what I'm attempting to do is as raw as it gets. I have no idea what I am doing, but I am learning as I go. Truthfully, I'm not working on an S-100 card, but I'm trying my hand at making a physical demonstration of how memory works for the average John Doe. The memory is using four AMD AM9101's, with two in Parallel to make 8-Bits. Then the second set of two to make 4Kb. This design was based on the Altair 680's 1KB memory board. Initially, it was just to read and write 0's and 1's using a bank of 8 LEDs for visual-aide, then I decided to use a hex to 7-seg LED driver IC. Now, it has evolved into a more practical and relatable setup, the output of the memory would go into a Character Generator IC, like a Motorola MCM6574, then output to an 8x8 LED matrix. All of this is still up in the air, but I think it would better explain how a raw text file works on the computer. I plan to use a similar 8-Bit input to the Altair, so the operator would have to study the 6574's character set for inputting the proper code. Maybe, I'll replace it with a keyboard.
I am still new to the whole PCB design process. Heck, I still haven't even taken "Engineering Design" at my community college yet (that will be next semester). I'm using the "learn as I work"-approach with KiCad. It took me a few days to come up with the hex to 7-seg. design on my circuit. On top of all that, it doesn't help that no one makes these chips anymore. I know experience really helps, but how does your design process work for creating these S-100 cards, is there a common template you use?
More generally though, it's amazing how easy it is for anyone to design and manufacture PCBs nowadays compared to 10 years ago. I am surprised by the vast amount of replica boards available to buy, like an Apple I motherboard or that Altaid 8800. To see people making S-100 boards again will spark a new interest in 8-Bit Microcomputers for my generation (Z). Heck, I didn't even know about the Altair until I watched Pirates of Silicon Valley when I was 12. On top of that, it will save older systems from being thrown out due to bad caps, faulty ROMs, or dead cards. The vintage stuff fetches astronomical prices, for what essentially is just 32KB of memory. A 512MB stick of SDRAM can be purchased for literal pennies.