Quote:
Originally Posted by demolition
Even if you do not add memory above $400000, the memory chips are still there and connected will respond to read accesses by putting data on the data bus, so the question is if it would still collide with the AR even if the PLCC was changed?
This is unless the PLCC is also used as address decoder so it is possible to turn off chip selects altogether? In that case, it should be possible to make it compatible.
As usual, I am always looking forward to new releases from Jens. I am also amazed by the release rate, particularly considering the retro stuff has low priority against his main projects. Some of his stuff have had issues where some was fixed, others was worked around and some persisted (normally minor ones). Most of the persistent issues as I see it, are specification issues where people expect it to do something it was not supposed to do or was written as a 'maybe' feature to some forum. This is the downside of being active in forums as a designer. 
I have quite a few of his devices by now and I have probably not bought the last one. |
I looked at the a608 source it has a chip selector decoder so it should be possible if he does it the same way.
I.e remove this
8'b010xxxxx: // $400000-$5fffff
begin
{which_ras[0],which_ras[1],which_ras[2],which_ras[3]} <= 4'b0100; // /RAS1
mem_selected <= 1'b1;
end
Disable autoconfig