ti 99/8 emulation/usage

[+mizapf]

I don't know whether there are differences in the ROMs, but I can easily show that the ROMs I have for the MAME emulation crash when Extended Basic II tries to load DSK1.LOAD. It is already a while ago, but I remember well that I had to investigate in that quite deeply because the floppy controller just did not work, only with Editor/Assembler.

 

What I found was that Extended Basic II sets up a PAB in CPU RAM, then passes the control to the floppy controller card, which believes the address to be in VDP RAM, where there are only zeros, and this is not caught in the Extended Basic II code, which crashes immediately.

 

The cartridges like Disk Manager and Editor/Assembler set up the PAB in VDP RAM as usual, which causes no problems.

 

If you were successful, as you said, I can only explain this by different ROMs.

 

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Anyway, if people like to work with the TI-99/8, just go ahead and take the HX5102. This one is working well. The only problem is that its double density format takes 16 sectors per track, not 18, but single density is the same as with the TI-99/4A. (And it requires a bit more performance from your computer, of course.)

 

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Edit: Just tested, the TI, BwG, and CorComp just do nothing. The DDCC1 and the HFDC manage to read sector 0 and return from the DSR, but then nothing more happens. So the DDCC1 and the HFDC seem to be able to handle a PAB in CPU RAM, but still fail. I just checked because at the time when I tried to get the floppy running in the 99/8, I did not have a DDCC1 emulation yet. I'd have to invest some more time to figure that out, but still I recommend to use the HX5102.