RE: D9090 ROM images uploaded to

From: Ethan Dicks (
Date: 1999-10-07 18:45:09

--- William Levak <> wrote:
> 300515-001 differs from 300515-002 by more than the first byte.  As you go
> through the code, other bytes are inserted in the -002 version...

Well, yes... I got as far as seeing that skipping the first byte took a
diff that was off with every line to a diff that was off by a few lines.
I accept that there is a 20 byte offset out of 2K.  I have begun glancing
at this code to see where PB5 and PB6 are being read from the 6522 at 4B.
Those are the jumpers that determine drive type (TM602S vs TM603S).

> The 8280 2K ROM is nothing like these ROMs although they are all DOS 3.0
> This suggests that that 8280 ROM image is not good.

Not necessarily.  The 2K ROM is for the CPU that interfaces directly to the
drive mechanism.  In the case of a D9060/D9090, it speaks SASI out the 6522.
In the case of an 8280, I expect that it's a WD 177x FDC chip.  This code
will be completely different once you get passed the commands passed through
the shared memory.
> 300516-001 appears to be C000-DFFF.

I agree.
> 300517-001 appears to be garbled.

I also agree.  I can see where the messages *might be*, but it's not a valid
ASCII or PETSCII stream (look around $FF76, for example).

Maybe I should set up a PET with a D9090, a 2031 and write a BASIC program
to M-R the ROMs out the IEEE port.  Not this week, though.  I never did get
my ROM programmer to read the TI 2564s.  I do have a Promenade (or is it a
Prom Queen?)  Perhaps I can read them there.


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