4 ms·
For a simple 8-bit system such as this, even if “no GALs” is a requirement, all the chips one would need can still be bought today, brand new, and are still in
by noone_youknow 3y ago
For a simple 8-bit system such as this, even if “no GALs” is a requirement, all the chips one would need can still be bought today, brand new, and are still in production in one form or another (e.g Alliance SRAM, SST flash, 74HCT logic etc).
Worth noting that 16V8 and 22V10 GALs are still being made too, and I’d argue that programmers for them aren’t exactly “outdated”.
Not that I have anything against this design, I’m always happy to see a new SBC, though it could be argued that it still “hides” more of the bus inside the MCU than would perhaps be ideal.
- kragen 3y agohow about cplds are cplds okay you can get currently-manufactured cplds for under two bucks https://www.digikey.com/en/products/filter/cplds-complex-programmable-logic-devices/695?s=N4IgjCBcoLQJxVAYygFwE4FcCmAaEA9lANrggC6AvvjAEyIgqQY75GSkCsFl1I9HRgAcANgBMeQA https://www.digikey.com/en/products/filter/cplds-complex-pro... and probably nobody is going to say that an lc4032ze or an atf1502 is faster than a z80 (i mean, it's literally faster, in the same way that a 74hc04 is, but you sure aren't going to emulate a z80 on it)
- noone_youknow 3y agoThe trouble with CPLDs in my experience is the software environments and (for some at least) programming hardware. Especially for the Atmel 15xx parts, the software is windows-only, old and annoyingly crash-prone. The GALs are at least programmable from modern OSes with commodity programmers. That said, the CPLDs themselves are good chips, and I don’t think especially inappropriate for a vintage project
- kragen 3y agowell, on the plus side, the cplds are thoroughly documented, right? no struggles to reverse-engineer bitstream formats or programming waveforms. so you can write your own software to program them however you like