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.

Tom wrote:
> 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.

You want the 25F serial FLASH devices, see
http://www.sst.com/news/?id=244

and also
http://www.atmel.com/dyn/products/datasheets.asp?family_id=668
-jg

maybe here..
http://www.ramtron.com/

"Tom" <t...@hotmail.com> a écrit dans le message de
news:TBrCc.864742$oR5.460604@pd7tw3no...
> 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.

Tom wrote:

> 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.
How about this one (M25P20):
http://www.st.com/stonline/books/pdf/docs/7736.pdf
2MBit SPI-Flash from ST

Jens

Hi Tom

> 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.

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

Reto Felix

> 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

Use only 256 bytes per page and leave the rest blank.
You loose 3% capacity.

On 24 Jun 2004 07:10:05 -0700, j...@hotmail.com (jetmarc) wrote:

>> 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
>
>Use only 256 bytes per page and leave the rest blank.
>You loose 3% capacity.

SGS-Thomson do some similar devices, I think they have sensible page sizes

In article <a...@posting.google.com>, j...@hotmail.com (jetmarc) wrote:
>> 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
>
>Use only 256 bytes per page and leave the rest blank.
>You loose 3% capacity.

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.