Re: New firmware for PseudoDisk / some problems

["Alex Freed" <alexf@mirrow.com>]

"David Wilson" <mcs6502@gmail.com> wrote in message
1164356809.431952.290000@k70g2000cwa.googlegroups.com">news:1164356809.431952.290000@k70g2000cwa.googlegroups.com...
>
> Just as I hit enter I reread the above sentence and noticed you said
> PROM and not CPLD as I thought.

Exactly. The low 8 address lines of the PROM are connected to the bus and
one more
is controlled by the AVR to switch between the Disk][ boot rom in nibble
mode and
my ProDOS driver.

> How many address lines reach the CPLD?

Only the low 4 to decode the I/O space.
The prototype boards have room for 2 extra chips. For example an 8 input AND
gate will be very handy for detecting access to $CFFx. The CPLD has plenty
of
unused logic but not nearly enough unused pins for the job.

Unfortunately the idea to make use of the C800-CFFF space occured to me when
the boards had been already ordered. I was thinking of using it for image
selection
code, but loading that from the SD card works fine.

-Alex.