From: "Cyrano Jones" <cyranojones_lalp@...>
Apr 18, 2004
wrote:
The dataflash (28SF040) has 2048 sectors of 256 bytes each.
And it is mapped into slot #4000 1 page of 16k (or 64 sectors) at
a time.
When any particular page of 64 dataflash sectors
is mapped to slot #4000,
The 1st sector is at #4000
The 2nd sector is at #4100
. . . . .
The 64rd sector is at #7F00
Try thinking of it from this perspective: If there is not
16k of dataflash occupying the #4000-7FFF memory space,
what else is???
You can think of the #4000-7FFF "slot" as a sliding window on a
much larger address space. The window is 16k high, and it
slides up and down in 16k increments.
You could design a system that slid the window on 256 byte
increments, and then you could put any arbitrary sector at
#4000-40FF. In that case, you would need 6 more bits of
"page" address.
Cyrano Jones