A Comparison of Early Graphics Cards

We have to admit, we expected to be bored through [The 8-Bit Guy]’s presentation, only to stay riveted through his comparison of early graphic card technology.

Some presentations get a bit technical, which isn’t bad, but what is so interesting about this one is the clear explanation of what the market was like, and what it was like for the user during this time. For example, one bit we found really interesting was the mention of later games not supporting some of the neat color hacks for CGA because they couldn’t emulate it fully on the VGA cards they were developing on. Likewise, It was interesting to see why a standard like RGBI even existed in the first place with his comparison of text in composite, and much clearer text in RGBI.

We learned a lot, and some mysteries about the bizarre color choices in old games make a lot more sense now. Video after the break.

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VGA Output On A Freescale

Even though VGA is an outdated and becoming somewhat deprecated, getting this video output running on non-standard hardware is a rite of passage for some hackers. [Andrew] is the latest to take up the challenge. He got VGA output on a Freescale i.MX233 and also got some experience diving into the Linux kernel while he was at it.

The Freescale i.MX233 is a single-board computer that is well-documented and easy to wire up to other things without specialized hardware. It has video output in the form of PAL/NTSC but this wasn’t quite enough for [Andrew]. After obtaining the kernel sources, all that’s needed is to patch the kernel, build the kernel, and build a custom DAC to interface the GPIO pins to the VGA connector.

The first thing that [Andrew] did was load up the Hackaday home page, which he notes took quite a while since the i.MX233 only runs at 454 MHz with just 64 MB of RAM. While our retro page may have loaded a little faster, this is still an impressive build and a great first step to exploring more of the Linux kernel. The Freescale i.MX233 is a popular chip for diving into Linux on single-board computers, and there’s a lot going on in that community. There are some extreme VGA hacks out there as well if that’s more your style.

VGA In Memoriam

The reports of the death of the VGA connector are greatly exaggerated. Rumors of the demise of the VGA connector has been going around for a decade now, but VGA has been remarkably resiliant in the face of its impending doom; this post was written on a nine-month old laptop connected to an external monitor through the very familiar thick cable with two blue ends. VGA is a port that can still be found on the back of millions of TVs and monitors that will be shipped this year.

This year is, however, the year that VGA finally dies. After 30 years, after being depreciated by several technologies, and after it became easy to put a VGA output on everything from an eight-pin microcontroller to a Raspberry Pi, VGA has died. It’s not supported by the latest Intel chips, and it’s hard to find a motherboard with the very familiar VGA connector.

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Driving WS2811 LEDs with…VGA?

We thought we’d seen it all. All the ways to drive WS2811/2812 “Neopixel” LEDs, that is. And then [Steve Hardy] comes up with a new one: hacking a computer’s VGA output to drive 500 WS2811s in a string. And it’s quite a hack. You can check out the video (it’s worth enduring the horrible wind noise) below the break.

bits[Steve]’s big realization was that he could send the digital data that the Neopixels needed by carefully selecting a resolution and clock rate for the VGA to match the timings that the WS2811 modules wanted. A resolution of 840×1000 at 28MHz produces 70 pixels per WS2811 bit, or 12 bits per line. This means two VGA lines need to be sent for the RGB triple for each LED, hence the 1000 rows.

There are some further tricks before [Steve] got around to writing a custom OpenGL shader that converts regular graphics to his strange black-and-white bit pattern to drive the LEDs, but you’re going to have to read [Steve’s] blog for all that. If you’re waiting for a full code write-up, [Steve] says that one’s pending.

We’re just stoked to see the computing power that lies within a video card used for other purposes. Once you think of the VGA output as a general-purpose high speed (analog!) output, it opens up a whole bunch of possibilities if you can write the corresponding video software. As [Steve] points out, he’s only using the red channel right now — he could trivially add another 1000 LEDs just by tweaking his video code.

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PSoC VGA on a $10 Development Board

We’ve always found the Cypress PSoC an interesting beast. It’s a CPU with functional blocks that you can configure to build various I/O devices, including incorporating FPGA logic using Verilog. [MiguelVP] has an excellent multi-part project that produces VGA output from a PSoC. So far it just generates a fixed pattern, but a frame buffer is in the works, and there is plenty of detail about how to configure the PSoC for the task.

Although the PSoC has some analog capability, [MiguelVP] uses a cheap R2R DAC and VGA connector to interface to the VGA monitor. You can get the same PSoC board the project uses for about $10. The software, unfortunately, is Windows-only, so be prepared to fire up a virtual machine if you run Linux or Mac. Our own [Bil Herd] did a video introduction to PSoC that you can watch after the break.

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ATtiny Does 170×240 VGA With 8 Colors

The Arduino is a popular microcontroller platform for getting stuff done quickly: it’s widely available, there’s a wealth of online resources, and it’s a ready-to-use prototyping platform. On the opposite end of the spectrum, if you want to enjoy programming every bit of the microcontroller’s flash ROM, you can start with an arbitrarily tight resource constraint and see how far you can push it. [lucas][Radical Brad]’s demo that can output VGA and stereo audio on an eight-pin DIP microcontroller is a little bit more amazing than just blinking an LED.

[lucas][RB] is using an ATtiny85, the larger of the ATtiny series of microcontrollers. After connecting the required clock signal to the microcontroller to get the 25.175 Mhz signal required by VGA, he was left with only four pins to handle the four-colors and stereo audio. This is accomplished essentially by sending audio out at a time when the VGA monitor wouldn’t be expecting a signal (and [lucas][Rad Brad] does a great job explaining this process on his project page). He programmed the video core in assembly which helps to optimize the program, and only used passive components aside from the clock and the microcontroller.

Be sure to check out the video after the break to see how a processor with only 512 bytes of RAM can output an image that would require over 40 KB. It’s a true testament to how far you can push these processors if you’re determined. We’ve also seen these chips do over-the-air NTSC, bluetooth, and even Ethernet.

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