We can buy hardware, we can repair hardware, and we can even restore hardware even when its initial conditions are terrible, but there are enthusiasts out there who don’t hesitate to raise the level of difficulty and start manufacturing their own hardware. One of them is engineer and developer Ben Eater, remembered for his spectacular DIY 8-bit computer. What’s next on the list? Nothing less than a video card with logic chips, four breadboards, and a bunch of wires.
Beyond The Snark Barker
A couple of weeks ago we talked about The Snark Barker, a replica of the Sound Blaster 1.0 that you can build yourself. Beyond the natural complexity of the project, at the end of the day it is more convenient for the enthusiast to follow that route because of the outrageous prices of the original hardware. However, The Snark Barker is not a board we can consider “educational.” If what really interests you is knowing how a component works as you build them, we have something better for you...
The worst video card in the world
… and it’s a video card. No, forget about AMD and Nvidia. I mean a video card at a fundamental level, the minimum necessary to generate a series of pixels on the screen. In fact, its creator Ben Eater named it “the worst video card in the world.” At first glance, anyone would give him the reason. Chips, wires, and a weak structure define its design, but the theory behind it is rich and abundant.
How it works
The 32-minute video has an introduction to the VGA standard, and what are the most relevant signals for its operation: Red, Green, Blue, H-Sync and V-Sync. The next step is to choose a resolution, and he opted for 800 x 600 with a “pixel clock” of 40 MHz, but with a difference: he lowered the clock to 10 MHz, thus generating 1/16 of the final resolution (200 x 150).
To create a horizontal line, the system must count 200 pixels, send a blanking signal, set the sync low, and send another blanking signal before it can draw the next line. The pulse durations are well documented, but with a 10 MHz clock, Ben had to make new calculations. That means you have to count pixels, and for that he uses a series of 74LS161 binary counters, which cost about 3 euros for a pack of 10 on eBay.
Unfortunately, this video does not reach the generation of signals and the presentation of images on a standard monitor, but knowing Ben Eater, it is most likely that the worst video card in the world will become a complete series. If you want to learn something new and you like computer hardware, you can’t pass this up.
Ben Eater on YouTube: Click here
