RE: D9090 ROM images uploaded to ftp.funet.fi/pub/cbm/incoming/firmware

From: William Levak (wlevak_at_cyberspace.org)
Date: 1999-10-08 06:40:27

On Thu, 7 Oct 1999, Ethan Dicks wrote:

> > 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.

Both versions of the 9090 2K ROM has valid 6502 code at the beginning, as
do all other controller ROMs.

The 8280 has a second 6502 for the controller side, but the 2K ROM is the
only possibility for it's operating code.  There is nothing that looks
like 6502 code.  There is also no controller chip in Bo's chip list, and
he says there are no other larger chips.

Unless they have swapped some data lines on the ROM, this is not a good
ROM image.

As for the 9060/9090, this looks like a standard IEEE dual drive setup
except that the 6530 is replaced by a 128x8 byte RAM(6810) and 2K ROM.
The I/O functions of the 6530 seem to be done by the controller board.
The manual says this has a 2900 series bit/slice processor(whatever that
is).  Page 6 of the schematics(188008) show what looks like a processor
and 4 memory chips.  However, the lettering on the schematics is
unreadable.  The numbers from these chips would help.

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