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Looking for large serial EEPROM or FLASH like Atmel's DataFlash

Discussion in 'Embedded' started by Tom, Jun 24, 2004.

  1. Tom

    Tom Guest

    I'm looking for a large serial EEPROM or FLASH chip that comes in a small
    package and uses a serial interface. I need something in the range of 1024
    kbit - 2048 kbit in an 8-SOIC or smaller package, and it needs to be as cheap
    as possible. :)

    So far I've only found I2C EEPROMs like the 24C512, but these only seem to go
    up to 512 kbit or 1024 kbit, and they also get very expensive when you go up
    to that size. Atmel has their "DataFlash" series which are fairly inexpensive,
    and they fit my needs in terms of package size and capacity, but the stupid
    264-byte page size and lack of linear addressing makes them almost unusable in
    my application. I just don't have enough CPU cycles left over to divide by 264
    every time I need to seek to a new location.

    Does anyone know of any other chips out there that have the same cost-per-bit
    as the DataFlash and also have the same ease-of-use as the 24Cxx series?

    Tom, Jun 24, 2004
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  2. You want the 25F serial FLASH devices, see

    and also
    Jim Granville, Jun 24, 2004
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  3. Tom

    Fred* Guest

    Fred*, Jun 24, 2004
  4. How about this one (M25P20):
    2MBit SPI-Flash from ST

    Jens Hildebrandt, Jun 24, 2004
  5. Tom

    Reto Felix Guest

    Hi Tom
    What is when You only use 256 byte per page?
    We are using the remining 8 byte for a checksum.

    Reto Felix
    Reto Felix, Jun 24, 2004
  6. Tom

    jetmarc Guest

    the stupid 264-byte page size and lack of linear addressing makes
    Use only 256 bytes per page and leave the rest blank.
    You loose 3% capacity.
    jetmarc, Jun 24, 2004
  7. SGS-Thomson do some similar devices, I think they have sensible page sizes
    Mike Harrison, Jun 24, 2004
  8. Tom

    Tom Guest

    I had this idea as well, but it doesn't work when you're doing a sequential
    read. The sequential read doesn't automatically skip past the 8 unused bytes,
    so you will get "gaps" of 8 bytes at the end of every page. So now I would
    have to keep track of the current offset within a page, and then remember to
    skip past the 8 unused bytes at the end of every page, and also clock the SPI
    at a faster speed (I'd have to change the CPU crystal here) in order to
    quickly skip past the 8 extra bytes and still get the next useful data byte in
    time for when I need it. This is just more hassle than its worth.

    As for the other suggestions that people have mentioned, here's what I've
    found so far:

    SST: Looks like a good choice, the SST25VF010 is 1Mbit and lists for $1.32 at
    future-active.com and SST also has 2, 4, and 8 Mbit versions.

    Atmel's 25Fxxx series: Looks OK, and the price for a 25F1024 is also $1.32 at
    digikey.com and they also have the 2 Mbit AT24F2048 for $1.87 but
    there's nothing bigger than 2 Mbit in the same family.

    Ramtron: The biggest device they have is only 256 Kbit.

    STMicroelectronics: Ok, first of all I HATE their website but the M25P10 looks
    like a good device and Digikey has them for $1.37, they also have 2 Mbit, 4
    Mbit and 8 Mbit versions for $1.76 and $2.10 respectively.

    Thanks for all the suggestions and keep them coming if you know of any
    companies that make serial EEPROM or FLASH!

    Tom, Jun 25, 2004
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