Archive for March, 2011

Wozanium Errata :-(

Sunday, March 27th, 2011

As I mentioned a few posts back, the Brain Board/Wozanium is a complex system and I’ve been bitten by a couple of small issues with the initial version 4.0 firmware.

The first few Brain Boards shipped (version 4.0 Wozanium firmware) have a couple of bugs. Because of the first issue, I’ll be shipping updated PROMs to those few individuals who were lucky enough to get the first units. Shipments going out after today will have version 5.0 firmware with these issues fixed. Here is the errata and workaround.

Errata 1:
Depending upon how the memory in your system powers up, the wozanium drivers could be clobbering the first few bytes of page zero memory. This will prevent the simple dump text example on the back cover of manual from working. It doesn’t look like BASIC uses these locations, so BASIC programs run fine.

Using the A1 monitor, set location $BC25 to 0.

Errata 2:
Upon power up, if reset is typed before the screen is cleared, there is a less than optimal display seen.

To avoid this, after power up, always clear screen, before typing reset. If you type reset first, you can always clear screen afterward with the right arrow key, with no harmful effects.

I was having a third issue, which was a picked pixel on the screen when running Wendell’s Star Trek on my system during the display of certain menus. The picked pixel was consistently the same, but the occurrence of the problem was very erratic. It would usually appear soon after powering up and would sometimes stop happening after reloading the program. After many attempts to try to get this to consistently repeat and detailed code review, I had strong suspicions that it was some kind of odd hardware issue. Running 3 different memory test utilities failed to uncover any memory problem. However, since re-seating the second bank of memory in my system, it has not reappeared. I’ll continue to try testing over the next week or so.

Before sending replacement PROMs to Brain Board version 4.0 firmware owners, I’d like to get mileage on version 5.0 and also make sure the picked pixel problem is gone for good. This will probably take a few weeks. If you are a version 4.0 owner and want updated PROMs sooner, rather than later, let me know and I’ll send them out now.

Apple IIc – first impressions

Sunday, March 20th, 2011


I’ve had Apple computers since I bought my Apple II in the first half of 1978. Within a year I had a job as a programmer for Systems Enginering Laboratories, and my interest in personal computers dissipated significantly. In early 1984, my home computer was upgraded to a 128K mac with imagewriter. Since then, I’ve been using macs as my primary personal machines.

It was only in 2004, when I pulled my original Apple II down from that attic in order to make a shutter tester, that I became interested again in the original Apple II line. Because my computer interests moved in other directions, I had little experience with the Apple II line since about 1980. Until recently, I never had any particular interest in the Apple IIc. It seems that it might be useful as a portable machine, especially since so many modern TVs have composite video inputs.

Well a few months ago, I was given a IIc without power supply. Since then, I’ve been very busy with the Brain Board and Mimeo 1 work and haven’t had time to cobble the power supply together. Well this morning I found a few hours and finally was able to bring this baby up.

First challenge was the power supply. Apple specs 1.2 AMPs DC at 15 volts. I have a Radio Shack (realistic) bench power supply rated at 1 AMP, with variable output, up to 25 volts, DC. I figured that since the power supply could be turned up to 25 volts that maybe it would source the 1.2 AMPs at 15 volts. After wiring the connector, I connected it up. The computer made a beep but then shut itself down. After several attempts, I realized the power supply couldn’t hack it and was shutting itself down. OK, now I’m looking for a wall wart with something close to the correct parameters. The first one that looked close, was rated at 1.2 AMPs at 12 volts DC. Now this same wall wart wasn’t hefty enough for the DISK II-USB project, so I was skeptical, but decided to give it try. I hooked it up with a voltmeter on the DC outputs so I could see how much the voltage sagged when the disk drive was turned on. To my surprise, this wall wart seemed to be able to handle the IIc, at least without anything external plugged in. It did sag down to around 11 volts at times, but I think the internal power supply will accept anything down to 9 volts. Ok, so now I have an Apple IIc powered up, what are my initial impressions.

Apple IIc test set up


  • First of all, the IIc’s disk drive is quieter than what I’m used to. It’s not silent, but certainly much quieter than the old Disk IIs.
  • The keyboard really isn’t that good. Maybe mine is old and out of shape but the keys seem clunky to me.
  • I run a lot of old integer basic programs and use firmware cards instead of language cards in my II and II plus machines. This isn’t really a knock on the IIc, I just have to make sure I boot with a disk that has integer basic on the drive. Same problem exists with the IIe, which is pretty much the same machine, only with slots.
  • It would have been nice, if they could have squeezed one expansion slot into this form factor.
  • For some Brain Board compatibility tests, I had to open up the machine to borrow the 65C02 processor. Though it is not hard to get into, there are some rather fragile tabs that help hold the case together. Be careful, if you decide to open this unit up.
  • I haven’t checked composite video compatibility with any digital monitors, but I’ll have to check that out before I actually try taking it somewhere.
  • Summary…Other than the clunky keyboard, I think that this is a cool machine and I may actually end up dragging it along on a trip in the future.

    First Batch of Brain Boards Shipping Tomorrow

    Sunday, March 20th, 2011

    The design is frozen and ready for general shipments. I’m now accepting orders and will be shipping the first batch of Brain Boards tomorrow.

    Send me an email, for ordering information.

    Brain Board Update #2 – Beta Almost Complete

    Sunday, March 13th, 2011

    The Brain Board/Wozanium pack web page is up and includes a link to the Beta Manual with has all kinds of information about the implementation. I have a little more to add, including an example downloadable driver that allows a user to control the machine through a super serial card.

    I have had some good feedback from the Beta team. Several improvements have been made to the Wozanium firmware and will undergo testing this week. I plan on starting general shipments on 3/21/2011.

    Cost for kits will be $59 with free shipping in USA and $10 shipping internationally. I also plan on offering built up units, once I get through any flurry of initial kit orders. Send me an email, if you have any questions.

    Datanetics Keyboard Enclosure

    Sunday, March 6th, 2011

    While I’m waiting for Brain Board beta feedback, I finished assembling the Datanetics Keyboard Enclosure I built to match my Mimeo 1 Enclosure. Here is the final result. Not my finest work, but it will have to do.

    Datanetics Keyboard Enclosure

    Datanetics Keyboard Enclosure

    Brain Board Update

    Saturday, March 5th, 2011

    I have shipped several Beta kits to some Mimeo builders who also have Apple IIs. Once I incorporate any feedback from the Beta Testers, I’ll open up for ordering. Hopefully this will take only a couple of weeks. My own testing of the production board has revealed no bugs.

    In some ways, this is the most complex retro-project I have yet attempted. There was a pretty decent blue print for the Apple 1 and Apple II projects. The complexity involved making sure I didn’t overlook any of the content in the blue print and filling in a few blank pages. The Brain Board project involves creating a way to map the blue print from one fairly complex architecture into another. It also involves mapping the software systems along with the hardware systems. With the motherboard projects, the software was a given. A similar project was the PS/2 to ASCII keyboard adapter, but that mapping is much more constrained.

    Several folks have suggested I take pre-orders for this project. Though demand on this project is hard to estimate, I think I have enough parts on hand to supply immediate demand and pre-orders are not necessary.

    I have decided to classify this kit as a level 1 kit – it is very easy to build. If you can figure out which end of a chip has pin 1 and have a decent soldering iron, you should be able to build it. Here is a list of projects that I have offered with their skill levels.

    1) Apple Cassette Interface (stocked), Brain Board (shipping soon)
    2) PS/2 keyboard adapter (stocked)
    4) Apple 1 (stocked), Apple 2 rev 0 (discontinued)
    5) Datanetics keyboard (several PCBs left)

    Brain Boards are in the house

    Wednesday, March 2nd, 2011
    Brain Board

    Brain Board

    During bring up last night, I had a minor issue with a dead 74LS74 and also found that 3 ohm resistors are not good substitutes for 3K ohm resistors. I’m now past that and am now looking at kicking off Beta testing this week.