glb_gtz's blog

Almost everything is finished. I have the floppies working 100%. The serial drive is working 99.99%. It works, but the original PC code I downloaded from the web does not have the checksum calculations. I might fix this someday, but not today. The only issue I see so far is loading the ROMs when the system is first plugged into the wall.

I am still have a few issues, but everything seems to be working. I have been playing Castle Wolfenstein of a floppy using a keyboard, not an easy task. I am working on the joystick hardware. I want to interface the standard PC type joystick, since that is what I have. It should be basically the same as the Apple joystick. I have the code written, now I have to build the hardware.

Finally the debug effort is finished. I traced the no boot issue to a bug in ProDOS. This error exists in both ProDOS version 1.2 and 1.9. But I see it has been fixed in version 2.0.1. I just need to do a work around in my ROM code to make sure I do not trigger this bug. Then I can continue firmware development of the Serial Virtual Drive. When I get this working, the floppy is the next task.

I have uploaded a couple of pictures. Look at my image gallery.

http://www.applefritter.com/image/uid/12920

Come to find out, the issue with the floppy is not the floppy at all. The system will refuse to boot ProDOS whenever there are two storage devices. I have a total of three storage devices, LPC ROM, HDT file located on a PC using a serial port, and the floppy. I have been using the LPC disk for booting. I tried a test, I booted using the LPC drive and I disabled the floppy.

I have been unable to fix the booting issue with the floppy. When the floppy ROM is loaded, ProDOS refuses to boot. Without the ROM, ProDOS happily boots from the LPC ROM all the way into the BASIC Interpreter. From there I am able to copy files from the ROM drive to the /RAM drive in the second 64K memory bank. The 80 column text screen works perfectly also.

Again crying / testing about the same.