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.
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.
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.