So for the past few weeks I've been building 1 bit registers. And I mean a whole bunch; 32 to be precise. For registers B through E of our 8-bit digital computer. And now I'm starting to wire them together. This is a circuit which implements the entire circuit we described in Introduction to Digital... Continue Reading →

A new quick video with a bit of a status update: I now have a working accumulator register tied to my ALU. (I'm also working on the flags register as well as the 4 8-bit registers B through E introduced in the "Introduction to Digital Computers Part 4" video. This includes video of the ALU... Continue Reading →

One of the boards I designed simply does not work. Worse, it's not a simple error: I can't simply cut one or two lines on the board and run jumpers. Turns out a bunch of resistors were incorrectly wired to power--and cutting them would require so much work it's easier to basically start over again.... Continue Reading →

Why build one when you can build 8, string them together in a primitive card cage and wire wrap the pieces together? This is the accumulator and the ALU together for the first time. I need to build a test circuit and verify the connections before I video tape this part of the work. And... Continue Reading →

So it turns out my 1 bit ALU--which has both circuitry for our accumulator and a tristate circuit to write to our bus, works correctly! Over the next week my plan is to assemble 8 of them and hook them up to my ALU.

They're nowhere near as complicated as the 1 bit ALU boards, but they do contain the accumulator circuit as discussed in our "Introduction to Digital Computers Part 4 video, along with a single tristate circuit for allowing the contents to be written to our bus, as discussed elsewhere in the same video. These accumulator circuits... Continue Reading →

One thing about my "Introduction to Digital Computers" series I wanted to verify was that all the circuits designed in the series in fact works correctly. And one aspect of that--which we introduced in the first part of the fourth video--was the complete ALU. While I've taken the liberty to do some minor redesigns (so... Continue Reading →

Okay, this took much longer than I wanted it to. But finally the fourth video for our Introduction to Digital Computer series! In this fourth video I start to tie the pieces together. We first finish the Arithmetic Logic Unit, then we tie it in with six registers: an accumulator, flag register, and four general... Continue Reading →