HowToChoose the right external memory for data storage

[strape81]

Hi forum users,

I try to figure out which is the right decision to make about the following case:

a microcontroller makes a measurement every minute. The data block (RealTime+meas_data) has a size of 8 bytes. These data are sent to an external memory. When the memory is full, then the old data will be overwritten. The desirable memory size is 1MByte.
As far as I know if I choose an EEPROM, I can read,write,overwrite or delete the data bytewise. In case that a flash memory is used, then I can read or write bytewise but overwrite or delete only sectorwise.
Did I understand their function correctly?
I am closer to 1MB EEPROM, what is your opinion?

 

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Someone correct me if I'm wrong, but I'm pretty sure EEPROM is not as cost effective as flash as it's not being actively developed as opposed to flash which is very active. If you choose EEPROM your vendor choices will be extremely limited.

I suggest you use a larger serial flash device (cheaper commodity product) and have one active (writing) and one inactive (reading) buffers. You can erase the inactive buffer (sectors) when you've finished reading the data from it (presumably before you want to write to it again). Those serial flash devices are very cheap and they come in very small packages.

Regards,
-alan


Update, unfortunately flash won't work in the OPs case as you need to do block writes to the flash . This part though looks interesting but I haven't read the datasheet for them.
http://www.ramtron.com/products/nonvolatile-memory/
from the description it looks like it might not require block writes/erase cycles.