Playing with 74LS181, a DIP-switch and some LEDs 9

Playing with 74LS181, a DIP-switch and some LEDs
I will be using 74LS181 ICs for my 16-bit ALU and I bought some today in a local hobby store. I decided to give a try with this little breadboard setup. It’s not really a CPU but it was fun. The inputs are set by the DIP switch. Switches 1-4 set the A input and ...

Instruction set

I mentioned in my last post that my intention is to design with a two-address instruction set. This means that my instructions will have zero, one or two operands. There is no important reason for this. I am familiar with 6502 (accumulator, one-address) and x86 instruction sets, and I am more used to the latter, ...

Kickoff

This site was set up to document my attempts to build a fully-featured, self-contained microcomputer using only basic logic elements (74-series TTL). The idea itself is nothing new and projects like this one are already out there (and completed – check my links page to see Bill Buzbee’s or Steve Chamberlin’s masterpieces which inspired me ...