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Mechanical CPU Clock
An anonymous reader writes "I designed this CPU clock to help people learn about how a CPU works. The Mechanical CPU Clock shows the basic building blocks of a CPU (ALU, buses, RAM, registers, and a Control Unit). It executes a set of instructions which will emulate a simple wall clock. A detailed build/explanation is available on instructables.com."
Looks like he's trying to serve webpages with a mechanical CPU or something....
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Are you still listening? This is something I would watch on Slashdot TV.
http://www.youtube.com/watch?v=0H4LTOYpAM4
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If you use this mechanical CPU to implement a clock, then how do you implement the clock of the CPU?
Brilliant work, but I find his terminology confusing.
From what I can see, there's really only one register - since the "registers" are linked, he can only store a 4-bit number (plus an instruction counter in the form of the track "flag"). "Register B" is really an instruction to clear both the register and the instruction pointer, and "'registers A&C"' are really an [inc A, if A<11 then IP=0 else IP=1] instruction. From this perspective, it's a two-instruction, one-register machine.
I only did that because I just couldn't get nine instructions and three different registers from watching the device function.
Am I the only one to see it that way? Are both ways (at least partially) valid?
You are right. The [inc A, if A11 then IP=0 else IP=1] is actually one instruction that was optimised after the first prototype. Originally I had these as separate registers with three other flip flops at the top for the program counter. However, I noticed that I can remove that (which made the clock simpler and more compact) if I combined both instructions together and only use one ball drop for the inc and check. I would love to figure out other ways of explaining this to people who don't even know there is a CPU in a computer. So any suggestions are welcome.
Reminds me of the Digi-Comp II that I had as a kid. It had the same rocker type mechanisms which simulated registers. See: "http://www.oldcomputermuseum.com/digicomp_2.html#"