A Blog About Random Computer Subjects
Introduction I recently (like a few months ago) stumbled onto an article about the Nibbler. It’s a 4-bit computer built out of discrete logic. There is no microprocessor, so this is lower level than slapping together a minimal system with a Z-80. Here’s the original article if you want to see what I’m attempting: Nibbler … Read moreA 4-bit Computer
My latest hobby is to learn VHDL and apply to the Mimas V2 FPGA board. As with any language, reading about the language is all well and good, but attempting a real application is where the rubber hits the road. I read through several tutorials and some introduction material to familiarize myself with some of … Read moreVHDL – Shift Register
After finishing the beginner’s guide for the Mimas V2 Development Board, I decided to try my hand at a circuit that I previously built with the GAL16V8 chip. I already had the PDS file for the BCD to Hexadecimal LED display, so I decided to try that. First, I needed to figure out what I … Read moreFPGA – Hex LED Display
I recently purchased an FPGA development board. Specifically, the Mimas V2 Spartan 6 board. There’s a really good introduction to this board which you can access by clicking here. The board looks like this: You can connect a micro-USB to USB cable to this board and program it from your PC. Plus, the power from … Read moreThe FPGA
In previous blog posts, I showed how the GAL16V8 operated and how to program it (see here and here). In this blog post, I’m going to discuss the differences between the 16V8 and the 22V10. Here’s the specification sheet for the GAL22V10: Lattice GAL22V10 Specifications. On first inspection, both devices look identical, except for the … Read moreProgramming the GAL22V10
When I wrote my blog post about building an ALU from an EPROM, I intended to use an EPROM from my old bag of parts. Unfortunately, none of my old UV erasable PROMs worked with the programmer. I’m assuming they are old and not usable. So I purchased a pair of 28C64’s from Jameco Electronics. … Read moreBuilding an ALU From EPROM – The Circuit
I’ve always wanted a decoder that did more than the TTL 7447 BCD to seven-segment display decoder did. I wanted the full hexadecimal output. One of my first real projects for the GAL was to create such a chip. I have an old PAL databook that was published by National Semiconductor in 1982. I pulled … Read moreGeneric Array Logic Hexadecimal Display
I’m going to continue this series while it’s still fresh in my mind. In case you missed it, part 1 is here. I learned electronics when I was in High School. I had two years of electronics classes and I also built circuits out of digital logic gates as a hobby. This is in the … Read moreDigital Electronics for the Beginner (Part 2)
I’ve been blogging a bit about digital electronics lately. One of the devices that I have never had the opportunity to experiment with is the Programmable Array Logic or PAL. The last time I built a circuit was when I was in College in the early 90s. At that time I owned a Mac Plus … Read moreGeneric Array Logic Devices
Let’s say you’re a programmer and your experience in digital electronics involves that one class you were required to take in college. Or…you’re a young person who is interested in learning this cool stuff, because, well… it seems cool. One option is to buy one of those learning kits and go through the tutorials. If … Read moreDigital Electronics for the Beginner