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Some of the most interesting projects in calculating are the "Just for fun," builds that individuals dream upwardly. A year and a half ago, we met the Megaprocessor, a room-scale CPU implementation with each and every component visible, clocked at a blistering 20KHz. At present we've got another from-scratch CPU implementation on a smaller scale, and its own unique window into the history of CPU design.

Paulo Constantino has built himself an 8-bit CPU implemented on breadboard, with a veritable explosion of wires running across the hardware to connect everything together.

All programming is done via DIP switches, and the CPU tin perform tasks like counting from 0-255, or playing an off-primal-but-recognizable-variant of the Mario theme. No shade for the incorrect notes; I can't even play the Mario theme on a pianoforte, much less program something else to play information technology for me.

Part of what's interesting nigh projects like this, and the earlier Megaprocessor, is the mode they demonstrate previous state of the art technology. Breadboards take all but replaced earlier methods of prototyping hardware, like wire-wrapping, but there was a time when this kind of CPU design procedure represented a cut-edge hardware implementation. We take modernistic-day PCB manufacturing and printed circuit boards for granted, but these technologies had to be invented.

The image above shows the wire-wrapped backplane of a Zilog Z80 organization, circa 1977. The Z80 was an 8-bit CPU developed by Federico Faggin, who also led the development of the first unmarried-fleck microprocessor (the Intel 4004), as well as several later Intel CPUs, the 8008, 4040, and 8080. The Z80 was a major improvement over the 8080, retained software compatibility with it, and is still in production today. Yous can encounter a distinct similarity between the wire-wrapping technology nosotros were using in the late 1970s and the modern solderless breadboard approach used today.

In this case, looking at the tangle of wires required for a simple 8-bit CPU illustrates how more than complex chips, with wider buses and more functions, required the creation of new mounting technologies. It eventually became impractical to wire-wrap a prototype. Increasing clock speeds and larger buses meant trace lengths needed to be controlled more than rigorously. The Megaprocessor similarly showcases a time when reducing the distance between function units and increasing component integration cutting costs, reduced power consumption, and led to long-term operation gains. Sometimes information technology'due south as interesting to run into where calculating used to be as where it's headed today. As for Constantino, Motherboard reports that his side by side goal is to integrate a keyboard, making his homemade CPU a bit easier to program.