On 12/22/13 9:08 AM, emanuel stiebler wrote:
On 2013-12-22 09:43, Al Kossow wrote:
Here is a first draft. Anything wrong/missing
architecturally?
Sorry, I guess I missed the whole discussion before, but what is the goal?
Emulating the CPU of the system, aka being the bus master to control the
peripherals to have access to old I/O devices, or
Snooping in a system?
There are two interrelated things. Legacy peripherals with no peripheral
controllers (DECtape, etc.) and CPUs with no peripheral controllers (TC08)
or peripherals (RK8E/RK05 combo). There is also the problem of debugging
legacy devices (how do you fix an 8E memory if you don't have anything that
works).
I have the problem that I have a lot of old media, a mix of peripheral devices
but no interfaces or computers to put them in. I also would like to come up
with a general solution that isn't OS or CPU specific.
From the hobbyist perspective, there are some peripherals that you just can't
find (RF08, TC08, anything for the PDP-15, etc.) even if you do have a working
computer.
So, how do you come up with something that isn't TOO hard to build, but you
can think of lots of uses for, which is what I've done.
Now, as usual whenever I think about this, I'll spend the next several weeks
trying to get a tool chain running to actually get "hello world" running on
an ARM proto board or the equivalent on an FPGA board. Maybe it'll actually
work this time (I think I've tried doing this for several years running now
and gave up when after buying a prototyping board I couldn't get anything
to work).