LEEK@QUCDN.QueensU.CA (07/30/90)
The following are to be released into Public Domain.
Disclaimer: The following information is provided as an idea and have not
been tested on a FRANCES board with < 4 meg of ram nor with
2.0 loaded. I trust these with my experiences in hardware
hacks, but I am NOT going to be responsible for any form of
damages to your machines.
To quote from the File: Setting_Jumpers in Programming_&_Jumper directory
on the disk that comes with you Frances disk....
"When the Amiga puts an address with the top five bits all logical 1, this
mean that this access is a KickStart access. The translation circuitry on
board will place the value you select with this jumper block on the top 6
address lines (A18 - A23 ) Due to the nature of the decoding A18, & A19 are
always logical 1. A20- A23 are generated from the J3 jumper block...."
The kickstart is to be mapped into 4c0000-4fffff, 5c0000-5ffff, 6c0000-6ffff
and 7c0000-7fffff for 1-4 meg memory configurations. To map 512K, we simply
use memory space X80000-Xfffff (where X is 4,5,6,7) To do so, we pass A18
through the translation logic by shorting the Pin 4 of the two 74F244 chips
(U52 and U53) together. That's all that are required to map the 32-bit ram
into f80000-ffffff space.
Now if Commodore/CATS can sell us a legal copy of 2.0 ROM (released version)
image on a floppy and one of us sit down and write a loader programer to load
it....
K. C. Lee (Die hard A1000 owner)
P.S. This doesn't stop me from working on the Kickstart hack for the rest of
the A1000 owners.
I haven't tested 2.0 for obvious reasons - I am not a developer !! I
have tested the operation by running 2 monitor programs. One to look
memory space f80000 and the other one let me poke stuff into 780000.