[vcf-midatlantic] First homebrew computer project
kd2dhp at gmail.com
Sun Jan 2 02:02:59 UTC 2022
Thank you for your expertise on the matter. I'm very much still learning
and appreciate any and all input. Getting to the point of layout and
assembly is probably months away, so I've got time.
On Sat, Jan 1, 2022, 8:42 PM Jonathan Chapman <lists at glitchwrks.com> wrote:
> My current inventory of MCS-80 components:
> C8080A CPU (gold/white)
> P8212 8-bit I/O port
> C8214 priority interrupt control (gold/white)
> (2) D8216 4-bit bi-directional bus driver
> D8228 system controller & bus driver
> (2) D8238 system controller & bus driver
> C8255 programmable peripheral interface (gold/white)
> (3) C2112A 256x1 bit SRAM (gold/white)
> Looks like you about have the contents of the SDK-80 starter kit!
> I'm sure I'm probably missing one or two crucial support chips.
> Just the 8224 clock generator, which is pretty important -- it's a hassle
> to do it without. Let me know if you need one, I have several NOS parts and
> around 300x Soviet clones (which run cooler anyway).
> I'll definitely need a bunch of a much higher capacity RAM, since 96 bytes
> just doesn't seem like enough. I'm pretty sure I have a ton of SRAM chips
> of more reasonable capacity but I just have to dig them out. Same goes for
> Realistically it makes the most sense to go with a 2716 EPROM or newer, as
> there are usually drop-in EEPROM options, and you can program with even
> modern-ish programmers. Plus they're typically 5V only after that point,
> except for some sort of oddball TI parts.
> As as far as construction and form factor, I was thinking about doing it
> on s100 prototype boards and a large backplane so that I could add
> commercially built cards to the system.
> You probably want to actually do S-100 then, there are better
> backplane/connector options if you're not actually going to implement S-100
> bus. Plus, as you say, that opens you up to a ton of ready made cards!
> I might eventually want to add a floppy controller. I know it would
> probably make more sense to use some type of flash interface, but I want
> this machine to be configured as if it was built in the late seventies or
> early eighties.
> Nothing wrong with floppies! That's mostly what I use.
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