Re: Disk ][ controller PROM

[sicklittlemonkey <Nick.Westgate@gmail.com>]

On Feb 25, 12:09 am, Steven Hirsch <snhir...@gmail.com> wrote:
> Does anyone know if the MMI PROM on older Disk ][ controllers has the same
> pinout as any of the 74S* programmable PROMs?  I'd like to read the contents,
> but would prefer not to let the magic smoke out of my programmer.

You can swap the P6 sequencer PROM with the P5 boot PROM to read it
from inside the Apple II as they are both 6309 parts. The address line
mappings are different, so you need to compensate for that.

This is described in great detail, with a program to decode the
sequencer PROM and full listings of the DOS 3.2 and 3.3 PROMs in
Sather's "Understanding The Apple II", p9-16.

I've been playing with this stuff for a while, so if you want the
files I can mail them to you, including Sather's program (and perhaps
some of my own depending on what you need).

Cheers,
Nick.