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Re: 6809 in an Apple II
I'm not sure what makes rev 1 different - I never even saw an actual Mill card and the schematics I have says rev "B".
BTW 6809E is very different from 6809. "E" stands for external clock and is the part used in (at least rev "B") Mill.
I have ordered PCBs on the cheap from China so it will take a couple of weeks till I can assemble a board. I gave up the idea of making an exact replica - to have the address translation for System09 a CPLD is called for and a lot more glue logic fits inside a CPLD. So I cut the number of chips by half while adding the functionality of the daughter board.
The original address translator used a TTL PROM - slow, power hungry and hard to get these days. One could use a PAL (or GAL) but a CPLD is actually cheaper with a lot more functionality. 


On 6/9/2012 9:23 AM, A2CPM wrote:

Hi, y'all!

On Jun 1, 5:09 pm, Alex wrote:
<--- snip --->

Clearly the emulated 6809 could be slowed down by a factor of 25 and
share the memory with Apple 2 ... not very exciting IMHO. If 10 people
wanted a clone of the Stellation Mill card, I could make the boards
using real 6809E CPUs available from Jameco.

<--- snip --->

     You probably do not want to clone revision A of the Mill card.
Just tested my rev. A Mill in a variety of Apple ][ models and found
that it will only work in an unenhanced IIe, or earlier.  Also,
replacing the 6809 with a 6809E will result in a Mill that will not
allow a II+ to boot.  Finally, the "DEMO1" program that displays an
updating counter on the screen is the ONLY program I have that works.
The "ASM09" program, a 6809 assembler, either won't assemble a source
file or fills the screen with garbage, depending on how you respond to
the prompts given by the assembler.

Willi