M9301-YB Bootstrap/Terminator ROM dumps / listings?
derschjo at gmail.com
Mon Apr 27 03:03:22 CDT 2015
On 4/27/15 12:05 AM, Josh Dersch wrote:
> On 4/26/15 11:01 PM, Jörg Hoppe wrote:
>> here some resources which may be helpful:
>> - can you run the console emulator?
>> To boot: Set all switches on the M9301 to ON and power on
>> OR enter 165020 LAD CTRL-START
> I should have clarified, I've been running with all switches set to ON
> (and after the fiasco with the SLU's address DIP switches, I confirmed
> that they're all actually closed :)). The console emulator does not
> run, either at power-on or manually (I wasn't aware it could be
> started from that address -- I didn't see it in the documentation but
> I'm sure I just skimmed over it...).
> At 165000-165776 there's just RAM (I have 128KW installed); At 765000-
> 765776 the ROM code appears. Should the ROM be getting mapped into
> the first 64K of the address space at power-up?
Answering my own question (I wasn't thinking w/the above) -- the front
panel will let me see whatever memory I want as a flat 18-bit address
space from 000000-777776 but the CPU only has a 16-bit address range,
and with memory mapping turned off the I/O page appears at the top of
the 16-bit address space. So when I peek at 160000-177777 from the
front panel I see RAM, but when the CPU is executing it's addressing ROM
in the I/O page.
I'm going to do a bit of disassembly tomorrow to see what the CPU's
executing from ROM and why it's halting. It's clearly time for me to
get to bed now, however :).
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