First post, by rasteri
I've been playing with PC104 CPU boards recently and was frustrated by how expensive it is to plug an ISA card into them. Most adapters are more than $100 and that seems ridiculous when you could probably make your own adapter reasonably easily using IDC connectors and ribbon cable.
But I was doing a big PCB order anyway so decided to spend a couple hours knocking up some boards, cost each less than $20 :
The small one leaves access to the main board but means that the card lies outside the PC104 footprint :
The large one sort of folds the ISA card back on top of the PC104 board and is probably more useful if putting the assembly in an enclosure :
I tested them and they work great! Here's a video of my old Ensoniq Soundscape Opus running on an Advantech PCM-5890 :
Gerbers for the boards can be found here (your fab house will need to be able to do 5mil trace/space) : http://rasteri.com/ISA_PC104_Adapter_Gerbers.zip
And the source CAD files are in Altium Circuitmaker's cloud : https://circuitmaker.com/Projects/Details/ras … o-PC104-adapter
This is just the first revision so don't go plugging anything irreplacable into it until I've done more testing, but they seem to work perfectly for me on all the cards and motherboards I've tried. There's no decoupling capacitors or anything since I figure most ISA cards will have plenty on board, and the traces aren't very long anyway. The power traces are thicker than the data traces but they could perhaps be even thicker, I don't know how much current an ISA slot is expected to cope with.
The designs are public domain, do with them as you wish.