Mike's PCjr Page

Well the boards came in and I already had the parts to stuff all three. Except I hit a bit of a show stopper snag. I'm a wire-wrap noob and didn't realize the pin diameter is about 3 times the pin size of a normal socket. So A) my plated holes on my PCB are too small, and b) the wire wrap pin tails ...

So you are certain that most of the IDE drives out there will tolerate a 16 bit operation to the 8 bit registers? I'm worried about how those things were implemented - there were a lot of corners cut. Even if it is allowed on paper it might not work on drives. It's not up to the host. All operation...

The 40 pin may be a problem then. And I'm not entirely sure what to do about it. Your points are valid except that I would like to point out the industrial flash modules also come in 44 pin self contained form. Which is pretty nice since they don't have an extra power cable. Your summary of the IDE ...

Both of those are easy in Eagle. While I haven't used KiCAD, I can't imagine a GPL package is more or even equally capable to commercial software ranging into the thousands of dollars and is already way under-featured for my needs (eg. anything to help impedance matched trace routing would be a god-...

Also I'd like any thoughts on maybe a repository where we can start aggregating design files.

I gotta say, that board does look a whole lot better than what I've got so far. I think I'll wait to hear your results with this before I proceed with anything else. :) Don't let me stop you. The CPLD approach was just an experiment. But for what little it will cost vs the time I already invested, ...

What do you think about a 2.5" HD sticking out the back of the sidecar about an inch? Here's a representation The long dash line around the edge of the image (except on the right) is the rough outline of the sidecar plastic profile. The short dash line is how far the HD would extend. Just a tho...

Checked the BIOS when I got home. It does check every address between C0000 -> EE000 in 2K increments. However the cartridge ranges (D0000 -> EE000) use a CRC where the option ROM addresses (C0000 -> CE000) use a checksum. So I'm not sure how much value there would be in adding configurable range su...

Most layout editors will allow you to specify minimum clearance between vias, pads, traces, board edge, etc. The auto router will respect that. Vias aren't a bad thing. Generally speaking though, manual routing cleans up the board to a degree you can often use larger trace widths with lower impedanc...

Hypothetically, if one were working on a design as a learning experience and it included... again hypothetically... - a 5V CPLD in a through-hole package - an extra RAM part - a 512K flash because of cheaper price and easier to find - and, via dip switch, allowed using part of the flash to provide t...