Let’s Build a Video Card

> Overall his projects are fascinating for anyone with interest in retro computing or learning how computers work at the lowest level

I'm on the RAM-building portion of the 8-bit breadboard computer for exactly this reason. I wanted to bridge the gap between (this is an electric circuit that lights an LED) and (this is how you can take a simple inverter and a logic gate to build a D flip flop, which can power registers, SRAM, and more) and (this is an 8-bit example of a Von Neumann Architecture computer).

His videos are perfect for that. Very well made and I don't have to take classes in circuit design or digital logic control & design at a college to learn the high level of how this works.

Ben Eater's entire catalog is gold, he gets right to the meat of things, clearly explains what's happening, and makes the subject matter accessible and entertaining.

His 8-bit CPU series made me finally understand how microcode works. His videos are very clear and well explained.

I'm curious how well that works out, building something that complex on a breadboard. I had an FM radio project that gave me a lot of trouble until I realized the breadboard was introducing a lot of parasitic capacitance.

A mod probably added the year - we'll take it out. Thanks!

Previous thread for those who are curious: https://news.ycombinator.com/item?id=20614129

Here's an entire demoscene demo on a microcontroller.

https://youtu.be/sNCqrylNY-0

DVI just encodes VGA signal in digital form :( Same for HDMI. Both are still sending pixels at VGA timings, Hsync/Vsync/blanking and all, with clocking locked to PixelClock.

DisplayPort is packetized, but not in a 100% sane way. You would expect that clean slate purely digital interface designers would at least optionally allow sending whole screen update at a time. Alas you are still sending same VGA formatted pixel stream (Hsync/Vsync/blanking), just chopped into TUs (32-64 symbol Transfer Units) with stuffing (aka never used garbage) between them, even when connected to eDP display supporting Panel Self-Refresh (own frame buffer inside display).

Technically less different than you might think, but it is much higher speed due to being bit-serial. The lowest pixel clock that must be supported by all devices is around 25 MHz (for VGA), which results in a bit rate of 250 MHz (8 payload bits per pixel per TMDS pair, encoded as 10 bits on the wire).

DVI is a very large spec. It supports everything from pure VGA over it's analog pins as well as full fledged HDMI (its actually the other way around, HDMI is secretly just DVI). Finding monitors which support all of the simpler modes is an issue, whereas finding monitors which support old school VGA is fairly easy.

Interesting idea. Basic DVI is somewhat VGA with analog signal replaced with TDMS. I think if you limit yourself to only few predefined colors with 8b10b encoding hardwired in shift registers, it's doable. (for signal integrity you can only pick colors that have balanced encoding)

edit: as pointed in other comment, lowest bit clock is 250MHz, which might be a problem, it seems fastest discrete logic chips are topping out at ~150MHz

The TMDS signals are a little too fast to implement in breadboarded logic, but DVI/HDMI are pretty easy to implement on an FPGA, especially if you restrict the colors used.

Likewise. I was tinkering with Arduino already but his videos got me hooked.

I've been watching his videos for a long time and as far as I can see, the goal is never technical sophistication or doing things in a "production ready" way. Rather, it's making the innards of a computer understandable. The way that he did it here, he could easily explain when and how the CPU had control of the bus and when the video card did _and_ he had a picture that he could point at to visually explain what was happening.

I've also noticed that he'll start simple and then layer on more complex things as the series progresses. No idea if he's planning on doing that here, but a good example was with the 6502 computer where he implemented it out of the gate with no RAM so that the video could focus on getting things up and running.

He's the Bob Ross of electronics. I find speeding up the video a tad helps keep my attention.

I've been having significant trouble sleeping the past few months. Even on calm-minded days, the second my head hits the pillow the stresses come back, I get worked up, and can't sleep. Rewatching his videos is one of the few things that has helped to quiet things down.

If I'm not in a hurry to learn something I love talks and explanations that I can watch multiple times and still learn something new because I didn't fully understand it the first time. That's why I also sometimes watch these kinds of videos while working.

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