Mike's PCjr Page

Ouch! $24.

If you wanted to give this a shot, I'll have a few devices in DIP packages here next week. Device simulators are great, but I don't really trust things until I get them on a board under a scope. So I can do that next week. I took a quick stab at translating the schematic logic into WinCUPL HDL. As I...

That's pretty easy. I suggest downloading WinCUPL from Atmel and have a look at the examples. I also have a programmer. I'm open either way. Need jmetal and Mike to chime in. But with a PAL, someone would definitely have to pre-order at least those, gang program them, and send them out individually ...

I think being able to program the thing in circuit via the computer itself is imperative and almost mandatory for a project like this. Once the XT-IDE was released the BIOS revisions and changes started coming quite rapidly, and there was even a second BIOS written for it by someone else (not Hargl...

I welcome it. But it's entirely up to you. Pre-buying parts opens up the possibly of significantly reducing the parts count with a little programming... but it requires programming. I just wanted to bring that up for discussion. Though not having to rely on someone for external programming is probab...

Were you able to find a socket that allows stacking of the 8088 directly on top of the original socket? The best I can come up with is a normal 40 pin 600 mil dip plus a double up/down pin 600 mil socket offset 100 mils to the side. Thought about using a wire wrap socket, but the tail pins would be ...

I was thinking the idea of a pre-purchased/packaged kit was definitely out. Too much upfront cost for someone. We could do a group buy on the PCBs, but you'd always want the option of Joe Smith downloading the Gerbers and ordering his own board from a quick-turn house. Then buy the rest with a (eg) ...

The EEPROM is used so that the contents can be programmed in-circuit after soldering everything onto a raw board. If you used PROMs or EPROMs, someone would have to gang program a bunch and send them out. Not many people have access to chip programmers.

You shouldn't run inputs directly to Vcc. The resistors are there to limit current to under what the part can sink. You'll need another network with the addition of the dip switches.

3) I see what you are doing now and we're saying the same thing about ALE. I never said it wouldn't work. It's just odd seeing it that way as the traditional means for ISA decode is by command strobes. Your solution is 8-bit ISA centric and could also be done by taking MEMR/MEMW through either a spa...