5200 ROM type?

[ricortes]

Back in the 90s I would guess I used my PB10 to read my 4 port 5200 OS ROM for some emulator type programmers. Needless to say, hard to remember details after a couple of decades.

 

So going over the schematics I see it is labeled a 2332 type. This makes half sense because I remember reading it as a 2532 which is pin compatible. It gets a little fuzzy from there as I remember an email conversation where I think we both thought it was supposed to be a 2k ROM<from Claus's article?> and something happened like it read as a 4k ROM with a mirror image. At the time I didn't go any farther, left it as either it was a 2k ROM being read twice because I was using 4k ROM setting or it was a 4k ROM with a mirror imagine.

 

I just loaded a monitor program and dumped the OS region and it came up with the same repeat/mirror image of the $F800 to $FFFF OS at $F000 to $F7FF.

 

Double checking the 5200 OS ROM file found here, it is only 2k.

 

Does anyone know off hand if the OS ROM really does take up 4k of memory map? The schematics show an A0-A11 device which is good for 4k of course. I don't have my PB10 set up yet and my other EPROM burner does NOT support older EPROMs so I can't burn 2532 to check. I'm not sure if the emulators would choke on a 4k OS ROM or otherwise know how to handle it.

 

Needless to say, I am rooting for it being a 4k window in the memory map with 2k available for expansion!

[CPUWIZ]

IIRC, the 5200 BIOS is actually only 1K, it lives at $FC00-$FFFF.

[ricortes]

Actual bios is 1k but they stuck some other stuff in there like a character set.

 

No matter, only way to check for sure is to do something like add a monitor to a 2532 and see if it ticks.