ISA

Playing with TIGA #2 – repair

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Our SPEA Graphiti HiLite 1024 2D graphics accelerator finally works. The repair was faster than expected – it took less than an hour. We just fixed the broken traces between the GPU and RAMDAC and that was it. The card outputs very sharp workstation-quality image even in 1152×870 and 256 colors. We are one step further to start programing it.

Playing with TIGA #1

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This is my new project for next few months – SPEA Graphiti HiLite 1024 – a TI TMS34020-based professional CAD card (“TIGA”). The video output does not work properly as some traces between the GPU and RAMDAC are bad, but the rest of the card seems to be ok. Once I fix it, I would like to play with the chip and program some benchmarks to see the real performance. It looks like TIGA cards are valuable among collectors, but there is very little info about what can be done with them. TMS340x0 chips are fully programable 32-bit integer CPUs and this (rather low-end) card has 1MB of program/data memory (in addition to 1MB of framebuffer memory). It is like a complete computer on a card.

These chips were used in the graphics subsystem of Sun 386i UNIX workstation and some CRT terminals (like DEC VT1000). There were even Amiga Zorro cards with these chips (boosted with TI floating point co-processors), but presumably the concept was too complicated at the time when most people cared just about BitBlt and basic acceleration of line drawing.

(fortunately, my Siemens Nixdorf PCD-4Lsx PC is just big enough to accommodate one full-size ISA AT card… the card is very picky and refuses to work on Pentium systems or anything with ISA clock beyond ~8MHz)

A Sound Card David Made 30 Years Ago

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This is a sound card designed and built by David (a friend of mine who does most of hardware repairs here on my tumblr) in the early 90s. He was a 15-16 years old high school student when he created this thing. It’s a custom design with 12-bit DAC, DMA support and connections for mono out and mono in. He was forced to use an 8-bit ISA bus because 16-bit AT prototyping card PCBs were not available in Czechoslovakia stores at the time (not long after the Velvet Revolution). There was also a problem to get necessary parts for stereo output.

The sound card is not compatible with any standard, so he wrote a program to playback wave sounds and created a “driver” for MODPLAY to playback tracker music. His reason to make his own sound card was simple – 8-bit Sound Blasters had worse sound quality and 16-bit sound cards were too expensive for him.

He still has one of the assembled cards, a prototyping board, all technical drawings and a WordPerfect document describing the design and operation of the card.

There is a quick video of the working card: https://www.youtube.com/watch?v=rL8u9aRfaK8

External Graphics Cards

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A friend of mine showed me a low-cost option to expand graphics capabilities of Atari TT030. VME bus was converted to ISA and a standard ISA VGA board could be used then. It looked very cumbersome to me and I was thinking how desperate one must be to do it this way.

After few months, another friend sent me the eGPU kit that allows to connect a desktop PCIe graphics card to a computer (laptop) that has only M.2, mini-PCIe or ExpressCard connection. I tried only the ExpressCard version but there are people who made holes in their laptops, removed a Wi-Fi adapter and installed a thin cable that can connect internal PCIe x1 with the external adapter. With an additional ATX power supply, huge compatibility issues and necessary OS hacks, this is even more cumbersome. Anyway, I’m pretty sure that there is a target audience even for this.

Looks like some people didn’t change much in almost 30 years.