Archive for the ‘Disk II-USB’ Category

Say Hi At VCFse in the Atlanta Area

Monday, March 18th, 2013

This year, for the third year in a row, I’ll be leaving the family in the care of our dog, Toby, and be spending a weekend with fellow retro-computer hobbyists. Since this years VCFeast, had to be cancelled, I’ll be treking down to VCF southeast in Atlanta for the weekend of April 20 and 21st. These weekends are always fun, so I highly encourage everyone that might be interested in these things to make the effort to join us.

Here is the link with informaiton for that event.

Stop by my exhibit. I’ll be operating a Mimeo 1 and a reproduction SCELBI 8H (one of a very few working SCELBIs in the world). I’ll even give you a chance to “drive”. Tell me you read my blog and get a free SCELBI/8008 reference card.

See you there…

Various Thoughts…

Friday, March 5th, 2010

Capacitors and transistors still not here, but I expect them any day.

Although I have more testing to do, I believe that the software for the PS/2 to ASCII keyboard interface is working the way I want it to. I still need to hook it back up to an Apple 2, as well as try a different keyboard(all testing to date has been with a single example). I plan on building a small batch of printed circuit boards, once I get a few of the Apple 1 kits shipped out. The Apple 1 project has been expensive and I’m going to need to recoup some of the investment before spending more money.

If you stick to acquiring old units through flea markets, word of mouth and yard sales, retro-computing doesn’t tend to be an expensive hobby. However cloning an obsolete design can get expensive, real quickly.

Now that the Apple 1 is nearly complete, my mind has been free to start revisiting some projects that are on hold. I have been looking to see if I have overlooked any internet data on the City Point and Army Line Model Railroad. So far, it looks like my previous research efforts have turned up most of what is readily available. Once the Apple 1 stuff has settled down, I plan on building an initial module in order to try out some construction techniques. I also have some thoughts about animating the layout using my Mimeo 1 as the brains. Animation of a layout in this era might be a bit different than more modern eras, since the internal combustion engine and electric power were not developed. However there was plenty of wind, steam, human and horse power available to move things around. Also the sounds of a busy wharf might make for some interesting computer controlled sound effects.

One other thing I’ve got on the drawing board, is putting together a short video podcast demonstrating operation of the keyboard interface and the Apple 1 monitor. Be forewarned, if you have subscribed to my podcast you might have a large file coming your way, in the not to distant future.

Disk II interface updates #17

Saturday, August 15th, 2009

No major progress this summer on the Disk ][ interface – too many distractions . The USB interface is pretty difficult, though I do have the Disk ][ interface recognized by a PC as a disk interface.

Beyond the usual family activities and homeowner maintenance projects, a few other projects have interfered, including constructing the microphone preamp that I needed to improve the quality of my podcast and research on the City Point and Army Line Railroad. I also just received good scans of an original Apple 1 circuit board, which may be the catalyst that kick starts an Apple 1 replica effort. Too many projects, not enough time :-(.

Disk II interface updates #16

Friday, July 3rd, 2009

Great news: I finally got the USB interface working well enough to get a command down to the processor handling the Disk ][ interface. The PC even recognizes a mass storage device. Now I have to work on some code that will handle those commands – my original code used ASCII commands from a terminal. I should be able to make faster progress now.

Disk II interface updates #15

Tuesday, June 23rd, 2009

Ok, did my deep dive of USB standards and think I have a handle on the technology.

I tweaked the code to make it look like a Mass Storage device using bulk only protocol to the host. The AVR handling the USB interface will simply transfer the USB mass storage commands/data/status between the AVR handling the disk interface and the USB bus.

So far the basic transfer is not working, but I think I have a good grounding on the technology, and now the process becomes a debug effort.

Stay tuned…

Disk II interface updates #14

Wednesday, May 20th, 2009

step 1, figuring out where the lost serial data went, is evolving into a complete investigation of the USB bus architecture and a relook at using CDC vrs Mass Storage device class and the V-USB(AVR-USB) implementation in general. The HW implementation is unlikely to change. This is likely to take some time.

Disk II interface update #13

Friday, May 15th, 2009

Good, somewhat surprising news. I programmed the AVR that is being used for the USB interface and the device attached to a PC on first attempt. So far I haven’t been able to get serial data through it, but just communicating with a PC is fantastic progress. Next steps…

1) Figure out where serial data is being lost
2) I’ll plug in the Disk ][ interface AVR and get some basic operations working
3) I’ll have to finalize and implement the host/Disk ][ communications protocol.

Disk II interface update #12

Monday, May 11th, 2009

Disk section of new proto board checks out – I’m able to read/write/format disks with same functionality as the first proto board. Inner tracks don’t seem to read quite as reliably as before, but I’ll look at this later on. Using a crystal for clock seems to be a good thing, because the format function seems to fit a track a little better on to a disk. I couldn’t tune that RC oscillator well enough to suite my liking.

Next step is the USB interface.

Mike Willegal

Disk II interface update #11

Friday, May 8th, 2009

Quick update – holes drilled and components soldered in (except for AVR’s, which go into sockets). Power supply checks out OK. I will be able to bring up USB and Disk interface sections separately. Communications between the two AVRs is through a serial interface and I have added a header which will allow me to interface from a RS232 port on a PC directly to each AVR, during initial bring-up. First, I intend on bringing up the Disk interface to state where I left it on original proto board. Some tweaks to the SW must be made because of change in AVR versions, but this shouldn’t take very long. Once that is working, I’ll bring up the USB interface. Finally I’ll combine the two and work on host protocol, which is the last major activity planned for this project.

Disk II interface update #10

Tuesday, May 5th, 2009

I have all the parts and etched the board this morning. Registration between layers isn’t as good as I’d like, but it will do for a prototype. It will take another evening to drill holes and solder in the components. Some of you may wonder why I go through the effort of making a PCB for a prototype. Well I think a PCB results in a vastly more presentable finished board and I like the esthetics of it. The result should also be a little more reliable than the results of other prototype processes. I don’t think that it is that much more trouble than say wirewrap or point to point prototyping. Finally, creating a prototype using the same artwork that a production house would use, makes going for a production run much less risky.

The board is designed to fit an a Serpac A20 enclosure, as used on my shutter tester project – This is not the cheapest enclosure, but I think it is a pretty good looking off the shelf box. I’ll have to come up with some kind of cool decal to put on top of it.

-Mike W.

PS In this image I haven’t yet removed the ink from the laser printer image that is used to form the resist.diskii-PCB