Retro ISA Card Means Old, Slow Computers No Longer Need Old, Heavy Monitors

One thing about vintage computers is that they depend greatly on whether or not one can plug a compatible monitor into them. That’s what’s behind [Tube Time]’s Graphics Gremlin, a modern-design retro ISA video card that uses an FPGA to act just like a vintage MDA or CGA video card on the input end, but provides a VGA port for more modern display output options. (Actually, there is also an RGBI connector and a composite video out, but the VGA is probably the most broadly useful.)

Handy silkscreen labels make everything crystal clear. Click to enlarge.

Why bother making a new device to emulate an old ISA video card when actual vintage video cards are still plentiful? Because availability of the old cards isn’t the bottleneck. The trouble is that MDA or CGA monitors just aren’t as easy to come across as they once were, and irreplaceable vintage monitors that do still exist risk getting smashed during shipping. Luckily, VGA monitors (or at least converters that accept VGA input) are far more plentiful.

The board’s design files and assembly notes are all on the project’s GitHub repository along with plenty of thoughtful detail about both assembly and troubleshooting, and the Verilog code has its own document. The Graphics Gremlin is still under development, but you can also watch for the latest on [Tube Time]’s Twitter feed.

Thanks to [NoxiousPluK] for the tip!

VGA Graphics Card In 74xx Logic

Feeling nostalgic we presume, [Glen Kleinschmidt] set out to build a 640x480x64 VGA controller card from discrete logic chips. If we ignore the 512Kx8 Cypress SRAM video memory, he succeeds, too — and on a very readable, single page A3 schematic. The goal is to interface some of his older 8-bit machines, like the TRS-80 Model 1 and the BBC Micro, but for now he’s running a demo using a 20+ year old PIC16F877 micro.

[Glen] provides all the schematics, Gerbers, and C source code on his website should you be inclined to reproduce one for yourself. He has three versions in the works, with various capabilities (there’s a table on his website). As an alternative, one could always use an FPGA or a custom-built chip such as the SSD1963 to generate video for these micros, but sometimes the urge to go retro is too great to resist. We get the feeling that for [Glen], this is a project unto itself, and being able to interface it to his 8-bit computers is just a convenient excuse.

This isn’t [Glen]’s first retro project, either. Check out his analog computer “bouncing ball” project we covered back in 2017. Have you struggled with the build vs. buy decision, and how do you decide?

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Pushing Pixels To A Display With VGA Without A PC

[Ben Eater] is back with the second part of his video series on building a simple video card that can output 200×600 pixels to a display with nothing but a VGA connection, a handful of 74-logic chips and a 10 MHz crystal. In this installment we see how he uses nothing but an EEPROM and a handful of resistors to get an image onto the screen.

The interesting part is in how the image data is encoded into the EEPROM, since it has to be addressable by the same timing circuit as what is being used for the horizontal and vertical timing. By selecting the relevant inputs that’d make a valid address, and by doubling the size of each pixel a few times, a 100 x 75 pixel image can be encoded into the EEPROM and directly addressed using this timing circuit.

The output from the EEPROM itself not fed directly into the monitor, as the VGA interface expects a 0 V to 0.7 V signal on each RGB pin, indicating the brightness. To get more than three colors out of this setup, [Ben] builds up a simple 2-bit DAC that allows for two bits per channel, meaning four brightness levels per color channel or 64 colors effectively.

See the video after the link for the full details. While pretty close to perfect, a small issue remains at the end in the forms of black vertical lines. These are caused by a timing issue in the circuit, with comments on the YouTube video suggesting various other potential fixes. Have you breadboarded your own version yet to debug this issue before [Ben]’s next video comes out?
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Hackaday Prize Entry: An Open Source Graphics Card

For last year’s Hackaday Prize, [PK] tried to build a video card for microcontrollers and headless Linux systems. It was only 640×480 resolution VGA, but the entire project was designed around a CPLD communicating with a microcontroller over SPI. This prize entry was, by [PK]’s own admission, a failure. It was late, but now he’s had an entire year to perfect his design. That means he can enter version two of his VGATonic in The Hackaday Prize.

The VGATonic version 2 uses a Xilinx XC95144XL CPLD for the VGA timing, and an ATTiny 2313a to read the SPI bus. Video memory is four megabits of static RAM. That’ls pretty much all you need for the most basic VGA graphics card, and all of this is packed onto a 3×3 inch PCB.

You can do a lot with 640×480 8-bit graphics running at 25FPS. In the video below, [PK] has a ‘hello world’ of sorts, Doom, running on a Raspberry Pi 2 with his SPI graphics card. Yes, it’s a graphics card for the Raspberry Pi, and it looks really good.

Further refinements of the design will include some primitive graphics routines. Not OpenGL or anything fancy, just something to reduce the number of writes on the SPI bus. It’s a great project, and perfect if you want to add video out to an Intel Galileo or other microcontroller project. [PK] has a video demo, you can check that out below.


The 2015 Hackaday Prize is sponsored by:

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external_laptop_gpu

Beefing Up Your Laptop’s Gaming Chops With An External GPU

If you’re not willing to shell out for a reasonably powerful laptop it seems that there’s not a ton that can be done to boost your gaming performance. That is, unless you have an empty Express card slot and the right chipset.

[Phatboy69] recently put together an external video card for his notebook, with fantastic results. His Vaio Z128GG had an Nvidia GT330M graphics card onboard, which is decent but nothing to write home about. Using an Express card to PCIe adapter, he added an external Nvidia GTX580 to his system, and he couldn’t be more pleased with the results. While the card does take a performance hit when connected to his laptop in this way, he claims that his graphics performance has increased ten-fold, which isn’t too shabby.

There are many variables on which this process is heavily dependent, but with the right amount of tweaking, some great laptop gaming performance can be had. That said, it really does take the portability factor of your notebook down to about zero.

If this is something you might be interested in, be sure to check out this thread over at the Notebook Review Forums – it’s where [Phatboy69] found all the information he needed to get his system up and running properly.

[Thanks, Henry]

A Masochistic Video Card

Have a penchant for pain? Why not destroy your fingertips with a wire-wrap tool building a video card made entirely out of discrete components.

When [Chris] decided to build an entry for the Dangerous Prototypes 7400 logic competition he already had his hands full. The 74xx chips he had on hand had a maximum clock frequency of 25MHz, but the VGA pixel clock runs at 40MHz. dividing the H sync timing by 4 means the maximum speed required of the video card is only 10MHz, albeit with a reduced resolution.

The video card was constructed on perfboard with wirewrap sockets. An 8-bit DAC was included, allowing the card to display 256 separate colors but only the three primary lines were wired up to the VGA cable. As is, the card cycles through 8 different colors in a constant loop, not bad for a pile of chips.

VGA out has been done on everything from an ARM to an ATtiny, but rarely, if ever, has VGA been done with discrete components. While this video card may not be our first choice for bitcoin mining, it’s still a very impressive build. Check out the walk through video after the break.

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Six Monitors, One Video Card

6 displays 1 videocard

With most of us utilizing at least two monitors these days in our day to day operations, six monitors, while an awesome thought, might seem a little too excessive. After all, do we really have space for multiple video cards?

AMD has a new setup in their testing lab that is running six Dell 30inch displays at 7680×3200 through a video card holding six DisplayPort connectors.

Maximum PC has the scoop on the setup, and they say that this single GPU will be coming out on AMD’s DirectX 11 capable chips. Details are slim with the amount of video RAM, speeds and cost not known at present.

Think of the possibilities! Trade shows are one thing, but how about a video wall at home for gaming and movies? How would you use the six monitors shown above? Be sure to leave your ideas in the comments.