von Gast » So 20. Mai 2007, 13:16
>I write in English this time, since that is easer for my<
I have installed the cartidge in my 800XL and it did nothing.
After checking the PCB for a hour, I noticed a little drop of
solder between D1 and D3..... Removed it and the Atari started!
Then I inserted a 74LS273 and a 29F020 (256k flash).
And the Atari still started up fine

With the switch to OFF, I found 48k RAM, no ROM.
With the switch to ON, I found to have ROM at $A000-$BFFF
I tried some registers at $D500-D5FF and made some little
programs with turbo basic. This is what I found:
$D500-$D57F: Turn ROM OFF and switch to RAM.
$D580-$D59F: selects bank 1 to 32 (32x8=256k)
$A000-$BFFF: 8k banks, selected by $D580-$D5FF
I found to have indeed 256k selectable with 32 banks.
This means the reading cycles from the cartridges is good.
I did some verify and repeatedly bankswitching, data is 100%!
Then I tried to erase sector 0 (first 16k block) by programming.
First write to $D580 to select bank 0, then:
AA to A555
55 to A2AA ,1st unlock cycle
80 to A555 ,command
AA to A555
55 to A2AA ,2nd unlock cyle
30 to A000 ,selected sector by address-decoding (=$000000)
But this did not work. No matter if the WRITE switch is to the
left or right. I tried other banks, to check if bits needed to be
inverted, but without succes.
Perhaps the creator of this hardware can report to this forum
and help me out?
Kind regards,
Sijmen.