Hi,

I am having a 64MB samsung NAND flash.
As per statics of 32 pages per block, 528(512+16) bytes/page, what will
be the available nof blocks??????
I read in spec that it is below 4000.
So they are counting it with 528bytes/page?????
or is it like only 512bytes/page so i can get all the 4096 blocks for
operation???

with thanks and Regards
AJ

Aj wrote:

The data sheet actually makes all of this completely clear.

You don't count the out-of-band bytes in the total "64 MB" size of the
device.

The 64 MB device has 128k pages of 512 bytes each. Since each block
has 32 pages, each block has 16k bytes and the whole device has 4096
blocks.

You cannot forget that the out-of-band bytes exist; otherwise your page
reads and writes may not be what you expect ...

-a

"Aj" <arunjr@gmail.com> wrote in message
news:1122361050.547273.103910@g14g2000cwa.googlegr oups.com...
I know it's not directly answering your question but what about
the 2% (average) bad blocks. Are there 4096 plus an extra
80 to replace the expected bad ones, or are up to 80 of the
4096 going to be bad?

tim

Hi,
So i am going to fix the nof blocks as 4096.

No.... no extra blocks for bad blocks....
"infact u never gets what u pay for..."
also u have to take care of those bad blocks which are formed during
its usage, any way samsung guarentees in their RBA algorithm that
count of bad block wont go beyond max of 200.

"Aj" <arunjr@gmail.com> wrote in message
news:1122361050.547273.103910@g14g2000cwa.googlegr oups.com...
Only 512 bytes are data bytes, the rest are used for logical/physical
block mapping (discussed later) and ECCs (Error Correction Code) for
error correction, which you will need, because NANDs are virtually
guaranteed to get single-bit errors.

If you are rewriting pages, the process is somewhat complicated - you
have to allocate another block of 32 pages, copy over the pages you are
not changing, write your changed pages, remap the block to be the new
logical block, erase the old block.

The way this is done, only 1000 of 1024 blocks per zone are used for
data, the remaining unused are used for auxiliary blocks (or unusable
as bad blocks). You need to keep track of those and use them whenever
a page is rewritten as noted above.

Those "extra bytes" contain the current logical block for the given
physical block, the ECC's for the data, and block status flags.

Use them.

However, using this information, you'll find that in a 64Mb flash, there's
4 zones, so 4 zones of 1000 data blocks yields 4000 blocks or 128000 pages

4 * 1000 * 32 * 512 = 65536000 bytes usable data

rather than

4 * 1024 * 32 * 512 = 67108864 data bytes with boot,bad,and free blocks

or

4 * 1024 * 32 * 528 = 69206016 theoretically writable bytes


Rufus