BMOW or Big Mess of Wires: Self-made CPU
With the big Mess of Wires (BMOW) Steve Chamberlin created a fully functional CPU from standardized logic elements. Pc Games Hardware delivers some information about the incredible project.
Inspired by the CPU Homebrew scene Steve Chamberlin started to build a self-made CPU which he named "BMOW-1” (Big Mess o' Wires). The idea behind this: To make a CPU from standard parts like adders, NOR elements, counters or Flip-Flops (1 bit memory) and other components. This CPU was supposed to deal with 8 bit programs just like the machines of the early 80s Steve Chamberlin grew up with. Furthermore there should be an option to connect it to a PC and the device was intended to be fast enough to run interesting programs (like chess games) at usable speed.
At this website Steve Chamberlin describes the whole construction of BMOW - from the first idea until the manual wiring of about 1,250 pins on an Augat board, which had preinstalled pins - a so called Wire Wrap board. The pins are at least plated with Gold and according to Chamberlin's estimation have material cost of more than 3,000 USD.
In some parts the wiring is so complex that up to 10 layers are stacked above each other. Steve says that when he was getting into it he was able to get up to 25 of these connections in an hour. From the pictures in our gallery you can guess what effort this must have been.
• Current frequency: 2 MHz (ca. 3 MHz theoretically possible)
• 512 kiByte RAM (Random-Access-Memory)
• 512 kiByte ROM (Read-only-Memory)
• Power consumption: 10 Watt (2.0 A, 5.0 V)
• Video: 512 x 480 Pixel, 2 colors; alternative: 128 x 240 Pixel, 256 colors
• Audio/Music: three voice, programmable
• TKeyboard: PC default with PS/2
• Text LCD for debugging with 24 letters, 2 lines
• ca. 1,250 wire connections (2,500 hand-made wire contacts
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