One Bit CPU Runs at a Blistering 60Hz

(*7*)

Should you truly assume exhausting about it, a CPU is only a very general-purpose state system. Smartly, maximum CPUs are, anyway. The MC14500 is a one-bit pc that has handiest 16 directions and was once intended to serve in easy duties the place a large CPU wouldn’t paintings for house, energy, or finances causes. On the other hand, [Laughton] took the theory one step additional and created (*(*(*13*)*)*)a single-bit pc without a actual directions to keep an eye on a printing press. The completed system makes use of a suave structure in an EEPROM to pressure an never-ending program.

In truth, we’d say that is extra of a state system, however we love the theory of it being a minimum CPU which could also be true. The design makes use of the EEPROM in an ordinary method. Every CPU cope with truly addresses a block of four bytes. The byte that will get processed is dependent upon the present segment and the standing of the one-bit flag sign in.

Every four-byte block has two sections. There are two directions that learn inputs and units outputs. The primary instruction executes if the flag sign in is fake and the second one executes if the flag sign in is correct. All the inputs and outputs are, after all, unmarried bits. The second one pair of bytes are two addresses for the following instruction. Once more, the primary instruction is for a false flag sign in and the second one is for a real flag sign in.

The I/O is a little atypical. Every segment (*(*13*)*) instruction selects an enter to retailer within the flag sign in and will set or transparent one of 7 output bits. After all, it’s possible you’ll now not need to write an output on every instruction, so there’s an 8th bit that isn’t attached. Writing to it has no impact.

There’s no exact RAM reminiscence, however the design loops again two output bits to the enter bits so as to retailer two bits and skim them again later. Actually, kind of an EEPROM-based state system however nonetheless a a laugh concept. We’ve noticed a couple of MC14500 builds, too, if you wish to to find out extra about what impressed this system.