[ECOS] flash base mask question

John Newlin jnewlin@rawbw.com
Wed Nov 12 18:07:00 GMT 2003


In file:

/packages/devs/flash/arm/uE250/current/include/uE250_stratflash.inl

There is a line that says:

#define CYGNUM_FLASH_BASE_MASK  (0xFC000000u) // 32Mb total



First question:
Does Mb stand for Megabit or MegaByte?


If Megabyte should the number not be?
~(1024*1024*32-1) which is: 0xfe00_0000  ( i wish c did underscore in
numbers like verilog)


If it is megaBIT then it would it not be:
~(32/8*1024*1024) which is:  0xffc0_0000


Or maybe the mask is per device?  There are 2 of these 32MB devices, which
would then make a total of 64MB and then the mask would make sense to my
simple brain.


If the numbers in the file are indeed correct, can someone please explain
to me how to derive the mask so that I can put the correct mask for my
device?

thanks

-john


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