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Here's to the systems programmers – Writing Hello World on a home brew CPU

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Re: Here's to the systems programmers – Writing Hello World on a home brew CPU

#31
post #24

Earlier quoted context omitted.

I'll give it a shot :) logic cells: easy, by universality of NAND. RAM: distinction between flip flops and RAM is unnecessary from a strictly technical standpoint. a massive (or not so much) array of flip flops with decoder and mux (also just made of NANDs) can get you by. ROM/flash: maybe I could argue NAND flash counts as just a NAND gate, but not quite. I'll concede nonvolatile memory with just plain old NANDs. Ma…

"I'll give it a shot :)" I admire your initiative. :) "logic cells: easy, by universality of NAND." Got me dead to rights there. Seems to be able to do anything boolean. "a massive (or not so much) array of flip flops" http://www.learningaboutelectronics.com/Articles/D-flip-flop... Close but still need the resistors. "May I suggest a" That's not a NAND gate but it's pretty neat. Thanks for that link. Especially as wh…

Those resistors are not part of the flop, they're just there to limit current through the LEDs to make the state visible. See here for a D flip flop: https://en.wikipedia.org/wiki/Flip-flop_(electronics)#/media....

My point was about Vcc and ground was just meant as a response to the "power-related analog components". If you don't already have a regulated power rail even a single NAND gate won't be able to do it's thing, so its definitely a requirement but if you say you are allowed a functional NAND gate you must be allowed power rails as part of that.

Re: Here's to the systems programmers – Writing Hello World on a home brew CPU

#32
post #31

Earlier quoted context omitted.

"I'll give it a shot :)" I admire your initiative. :) "logic cells: easy, by universality of NAND." Got me dead to rights there. Seems to be able to do anything boolean. "a massive (or not so much) array of flip flops" http://www.learningaboutelectronics.com/Articles/D-flip-flop... Close but still need the resistors. "May I suggest a" That's not a NAND gate but it's pretty neat. Thanks for that link. Especially as wh…

Those resistors are not part of the flop, they're just there to limit current through the LEDs to make the state visible. See here for a D flip flop: https://en.wikipedia.org/wiki/Flip-flop_(electronics)#/media... . My point was about Vcc and ground was just meant as a response to the "power-related analog components". If you don't already have a regulated power rail even a single NAND gate won't be able to do it's t…

I'll be darned. So, NAND gets some extra points on the flip flop. Far as analog, even if I ignored power rail we still have ADC's, DAC's, etc. This time I hesitate as I say I doubt they'll be implemented just with NAND gates.
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