A place to learn about coding, making things, and stuff that strikes my fancy.
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 →
So this one is a little different; in this video I show the steps to go from the design of an arithmetic logic unit to actually demonstrating a working 8-bit ALU, made entirely out of 2N3904 transistors. The show notes include links to circuit diagrams and files in case you may want to build your... 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 →
So here's a quick little Arduino project which combines an Ethernet shield, a display shield and an Arduino-compatible Adafruit Metro to display the current weather and forecast. The goal of this project was to pull weather data from a remote server (in this case, the DarkSky API) to display the current temperature, weather and a... Continue Reading →
So here's where the next video stands. First, as I noted in a previous blog post, I've settled on an 8080-like MPU with 6 8-bit registers and an internal 8-bit bus. Now to make an internal 8-bit bus work, you nee a tri-state gate, a logic circuit which can be used to disconnect our logic... Continue Reading →
So one of my goals of my series "Introduction To Digital Computers" is to show the design of a computer that can be built entirely out of NPN transistors. The idea is that by showing the design of a digital computer from the absolute ground up--from something you can hold in your hands rather than... Continue Reading →
