interesting stuff!
If you don't mind me asking, how much did you pay for the pcb DK?

He charges $30 I think plus shipping which is cost price. I bought it nearly a year ago and just never got around to doing it, so maybe that price has changed.

It's too bad he didn't base his project around the 8086 instead. Then he could have used that 16-bit backplane to develop a proprietary 16-bit bus for expansion boards. 8086 was a true 16-bit chip, but very few systems based on 8086 made full use of it. 16-bit ISA can't really be utilized with 8086 though since it requires 24 address lines (8086 only has 20), but if proprietary firmware were written for say a VGA card there would be a tremendous benefit from having the 16 bit databus. Same goes for EMS memory expansion.

I'd also like to know what happens if you try to run 13.3MHz turbo mode on a system equipped with an 8087...I probably don't want to know.

@DK
very nice price and a cool project, I predict fun times ahead building it 😀

It's too bad he didn't base his project around the 8086 instead. Then he could have used that 16-bit backplane to develop a proprietary 16-bit bus for expansion boards.

While that is true it would have increased complexity significantly. He's gotta start somewhere and I think this is pretty impressive for the first model 😀

Anonymous Coward wrote:

16-bit ISA can't really be utilized with 8086 though since it requires 24 address lines (8086 only has 20), but if proprietary firmware were written for say a VGA card there would be a tremendous benefit from having the 16 bit databus. Same goes for EMS memory expansion.

Could he still have done a "fake" AT bus with the extra DMA and IRQ channels? Most 16-bit cards just need that along with the 16-bit data bus (like IDE).

I suppose cascading the extra DMA and IRQ controllers ala AT style shouldn't be too difficult. I wonder if there were any XT clones out there with proprietary expansion buses that did that.