> I have 2500 binnary values of 64 bits each to
load in eeprom, using I2C
> interface and PIC16F877 microcontroller. I
think that this size require about five 256 kbits
> eeproms.
Well, 2500 * 64 = 160000 bits, which would easily
fit into just one! 256kb eeprom. If you can write 8 bytes to the
eeprom at a time (using the page write mode of a 24LC256, for example), it would
take 2500 writes to write your data. At 5ms (per data sheet) per
write, that's 13 seconds (not counting data xfer time). Is that still
too long for you?
> usart and write in eeprom routines, but this
will be too long !
If you like the 24LC256, but want faster write
times, you can use multiple eeproms. For example, you could use a bank
of 4 eeproms. Write the first 64 bits to the first eeprom, and start
it's write cycle. While it's in it's write cycle, you can use the I2C
bus to write the next 64 bits to the 2nd eeprom, and start it into it's write
cycle, and so on.