Hi Guys,
Glad to join the discussion!
It was the summer break after my first year in grad school when I started the SIMMConn des […]
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Hi Guys,
Glad to join the discussion!
It was the summer break after my first year in grad school when I started the SIMMConn design. At the time the AWE64 was the cream of the crop of sound cards. I couldn't afford the Gold version, let alone the Creative memory modules. Using the 72-pin SIMM seems to be the most economical way to put more memory on the AWE64.
Unlike the Creative memory module which is a straight-forward design, there is some more work to do in order to accommodate a SIMM. The SIMM has 32-bit data bus, whereas the EMU-8000 uses 16-bit. I would need to multiplex the 32-bit memory into the 16-bit bus base on the address range EMU-8000 accesses. At the same time, the memory refresh command needs to be duplicated to the other half of memory that's not being accessed, otherwise the content in the memory will be lost. I managed to squeeze all the logic into a GAL device and made the first prototype.
I convinced my dad that people who are like me would buy these. With the investment from him I had 500 pieces of adapters made (250 of Value and 250 of Gold), with printed manuals and nice looking, colorful retail packaging. It turned out to be the worst investment he has ever made. The AWE64 was soon replaced by the PCI sound cards. After the first 50 or so, the quarterly sales of the adapter dropped to near zero. Interestingly, sales slowly picked up after around 2005, and 2014 was the best year until the stock ran out.
Around the time the prototype was finished, I found the AWE-SIMM website by Jeff Briden and had some good email conversations with him. Apparently his adapter was based on the same principle but in a slightly different implementation. Memory expansion was fixed at 16MB and DIP parts were used which are more DIY-friendly. Inspired by his openness about his design, I decided to open my design as well and posted all the manufacturing files on the website.
The PCB is a simple 2-sided board and all the parts are easy to get except the 2mm pitch dual-row receptacles that mate with the headers on the AWE64. I custom-ordered them from Taiwan. The PCB was designed to accommodate both straight and right-angled SIMM sockets with no modification needed. At the time I was not able to find a right-angled one. It turns out even with a right-angled one the stacked height is still too tall. To tuck all the memory within the allowed space of an ISA card, one would have to go with the Creative memory module approach and have the memory chips soldered on the module.
All the adapters were supposed to be tested in 1998 and I had no idea why I ended up with a box of untested SIMMConn Gold. My apologies go to everyone who asked about it in the past year or so, for the long delay. I was finally able to test all of them and most of them are good. So here they are again on ebay. There should be enough for everyone in this thread. Unfortunately the last shipment of Value boards was inadequately packaged and every board suffered some damage. I picked the ones in fair to good conditions and they are mostly gone now.
Please feel free to use the design files to run another production. One should be able to make it a wash for a group buy in the neighborhood of 25. I’m not planning on doing it myself, as I have other projects in desperate need of my time. Anyone who’s willing to take the plunge and do it, feel free to contact me if you have any technical questions.
I’d like to say thanks to everyone who inquired or ordered a SIMMConn at some point of time in the past 17 years. Having satisfied customers around the globe is the best reward I can possibly get for the effort I spent on this project.
Best regards,
Xu Wang
