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You can use any size, it makes very little difference, although at a certain point the interface in the EEPROM changes from one address byte to two address bytes - you need to be aware of this in your programming.
If you check my I2C tutorial I give code for both types.
Ahh...so i c....
the limit is not explicitly implied..but rather due to the limitations of the I2C bus addressing method which is limited to 2 bytes or 16 bits long.
Allowing you access to 65535 bytes which incidently is 512Kbits...The mother of all Serial EEPROMS manufactured by Mircrochip.....So...if I wanted to have presisistent memory in excess of 512Kbits, I will put in more serial eeprom.
Ahh...so i c....
the limit is not explicitly implied..but rather due to the limitations of the I2C bus addressing method which is limited to 2 bytes or 16 bits long.
Allowing you access to 65535 bytes which incidently is 512Kbits...The mother of all Serial EEPROMS manufactured by Mircrochip.....So...if I wanted to have presisistent memory in excess of 512Kbits, I will put in more serial eeprom.
You are not limited to 2 bytes with the I2C bus itself. After you initiate a start condition, you can transmit as much as you want before you send your stop condition. The 2 byte limit you are thinking of is the limitation of the controller on your I2C EEPROM. All microchip would have to do is adjust their hardware to accept a 3 byte address and you will have a whole new class of EEPROM. The other possibility is that each address could correspond to a "page" in memory and from that you would have to sequentially access say 32 bytes of data. This would also break you out of the 512Kbit limitation but it wouldn't be as fast as a normal EEPROM for random access.
If you're willing to consider a different serial interface, Atmel's dataflash parts (basically a flash EPROM with a serial interface) are a good alternative to high density serial EEPROMs:
NOTE: Now entering a resurrected thread from year 2004, but relevant today...
Hello,
I was looking for the largest EEPROM also, either I2C or SPI or something like that.
I see the 'normal' ones go up to 2M bits now, which translates to 256k x 8 bits.
So that means 262144 storage bytes.
That's not too bad, but then i see the Atmel (or similar) 64M bit DataFlash memories, and that translates into 8M bytes.
Even the 32M bit translates into 4M byte, which would probably be enough for my app, and the cost is around $3 USD.
So the question is, has anyone tried this type of EEPROM yet?
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