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by tyingq 2540 days ago
"From 7400 series devices, which are very simple integrated circuits by modern standards"

So it's clear, a 74xx is just a bunch of NAND gates. Nothing at all higher level than that.

3 comments

Except they're not. He's using 74161 counters; that's a MSI device, not just primitive combinatorial logic and flip flops.
Ahh, good catch. I was distracted with the 7400 description. Though a 4 bit counter isn't terribly high level either.
Counters are a series of flip-flops anyway, right? And a few latches for reset and load.

https://easyeda.com/normal/74161X2-4qkCwOIZh.png

Although NAND gates are universal gates (any combinatorial boolean logic function can be built from nothing but NAND gates), in practice it's usually more space efficient to use a mixture of different gates.
And usually more power-efficient and faster in execution speed.
Among my group of SW engineering circle, we had a running joke that software is a series of 1s and 0s, it is the sequence that is important.