In the nearly 18 months since a CD-ROM-based “Nintendo PlayStation” prototype was first found in an estate sale, emulator makers and homebrew programmers have created a facsimile of what CD-based games would look like on an SNES. Efforts by hacker Ben Heck to get that kind of software actually working on the one-of-a-kind hardware, though, had been stymied by problems getting the CD-ROM drive to talk to the system.
Those problems are now a thing of the past.
In a newly posted video, Heck lays out how the system’s CD-ROM drive suddenly started sending valid data to the system literally overnight. “I was working on this yesterday and the CD-ROM wasn’t even detecting the disc,” Heck says in the video. “I came in this morning and jiggled the cables around and got ready to work on it some more, and all of a sudden it works… did a magic elf come in overnight?”
I’m a sucker for exotic game hardware.
I wonder what kind of additions might have been added to the hardware layer on the development process. As it is, all the the CD offered was extra storage, but the buffer so the SNES could pull data from at cartridge speed wasn’t to bug, at point 256KB. Unlike the Sega CD, this didn’t upgrade video hardware, either (though, sound hardware for a boost).
After thinking about it some, I’m pretty sure the SNES could have handled some full-screen FMV off of the CD, without additional hardware, provided it was encoded right, and even still had enough data left over for audio to go along with it.
My back-of-the-envelope calculations suggest 186KB/second bandwidth needed to keep the RAM buffer on the CD with fresh data, and the SNES-CD has a 2x drive, which can do 300KB/sec.
TASBot can : https://www.youtube.com/watch?v=Ukq29ePnTqI?t=55m55s
Correct link : https://www.youtube.com/watch?v=Ukq29ePnTqI&t=55m55s
The SEGA CD didn’t upgrade the video, no matter what those “256 color!” ads say. Here’s what it added:
12.5 MHz 68000. Yes, another CPU.
512 KB of ram for that 68000 for programs and data.
256 KB of ram that could be swapped to the Genesis side for transferring data… mainly tile data for the Genesis VDP.
An ASIC that could rotate and scale rectangles of pixels in memory. This would allow scaled/rotated sprites without using prescaled/rotated sprites in the ROM, which consumed lots of space. This is the only “video” update. It was a pretty flexible blitter, and one of the very first things they did using it was make a couple of “Mode7” games to show that Nintendo wasn’t the only ones capable of Mode7-style games. With some effort, you could do some pretty cool stuff with the ASIC – it was just short of being a full-fledged texture mapping processor. The ASIC could only work on data in that 256KB of swap ram.
A PCM audio chip with 64KB of audio ram. This gave the SCD eight channel, panning, envelop modulated digital audio. The 64KB was a bit tight for sample storage, especially as it didn’t support compressed samples.
A CD interface with 64KB of sector cache ram, and a 1X CDROM. The slow speed was the main limitation here. You can’t really pull data off it fast enough for GOOD full motion video. So you got rather crappy CINEPAK video instead. The CD interface could DMA the data straight to the 68000 program ram, the ASIC swap ram, or the PCM audio ram, so the CPU wasn’t tied up transferring data from the CD, it could be doing things like decoding CINEPAK data.
It’s impressive to watch him pull the thing apart on the operating table and help create an emulator. That’s an impressive skillset that I haven’t seen much. Everyone does software but it doesn’t seem like very many people do hardware at that level.
They do.. they just don’t get online and boast about it.
What’s the old saying? It’s not boasting if you can actually do it? Anywho, it’s a video program he runs to make a bit of money while giving interested parties (like me) a chance to see what someone with talent in the field can do with various pieces of old hardware. I love his show. I soldered boards as part of my job when I was younger, but I was never so good with my hands. He’s a virtuoso of hardware.
You’re probably just looking in the wrong places. Fewer people do hardware in general because you typically need more gear for it than software development, but plenty still do it. Check out the forums related to homebrew hardware for classic machines like the C64 – homebrew network cards, SD card readers and so on.