Good catch. This sure explains the mystery of OS9 boot code:
With this new remapping the reset vector should be in Apple's $AFFF.
That happens to be $a84b. A look at HUH.LST disassembly shows that
$a84b is good 6809 code, in fact just the beginning of a code
section in what was assumed by Willi to be initialization.
Fortunately changing the memory mapping is trivial with a CPLD. I'll see
what happens now.
In other news I ordered a few 6809E chips from Hong Kong. With any
luck they should be real "E" parts.
Thanks everybody who sent me a payment. Please expect a little
delay till I investigate the memory mapping issue and more delay
till the CPUs arrive - promised in 2 weeks.
On 7/30/2012 6:06 AM, rjustice@internode.on.net wrote:
Might be worth a try.
-Alex.