FM24C256 serial EEPROM, doubt in page write mode

[CCD]

Hiii,
I was just interfacing my ATmega128 uc with FM24C256 EEPROM on i2c
bus. The datasheet of the eeprom mentions a Page Write mode, where it
says that the memory is devided into pages of 64byte each, starting at
addresses 0x0040, 0x0080..and so on.
the datasheet says that in page write mode we can continuously write
max of 64bytes and if more byte are sent to the eeprom, they will roll-
over to the starting address of the page, rather than getting written
into the next page.
So, i wrote a code to write n read the eeprom. It works fine.
now, the doubt is, when i sent more than 64bytes continuously, the
excess bytes are getting written into the next page rather than
rolling-over and getting written to the same page beginning, which i
confirmed by reading the pages one by one.
well, this doesn't do any harm, but i'm just curious, how come
datasheet is wrong?? or did i misunderstand something??

Thanx.

 

[Mike Harrison]

Hiii,
I was just interfacing my ATmega128 uc with FM24C256 EEPROM on i2c
bus. The datasheet of the eeprom mentions a Page Write mode, where it
says that the memory is devided into pages of 64byte each, starting at
addresses 0x0040, 0x0080..and so on.
the datasheet says that in page write mode we can continuously write
max of 64bytes and if more byte are sent to the eeprom, they will roll-
over to the starting address of the page, rather than getting written
into the next page.
So, i wrote a code to write n read the eeprom. It works fine.
now, the doubt is, when i sent more than 64bytes continuously, the
excess bytes are getting written into the next page rather than
rolling-over and getting written to the same page beginning, which i
confirmed by reading the pages one by one.
well, this doesn't do any harm, but i'm just curious, how come
datasheet is wrong?? or did i misunderstand something??

Thanx.

There are subtle differences between manufacturers of eeproms, and page-write behaviour can be
different. If you have the correct datasheet for the maker of your eeprom, it is also possible the
that datasheet has been copy-and-pasted from previous versions and they didn't update it properly.
Or they did a die rev.

The wrap-to-start behaviour is rarely useful, so people would be unlikely to notice as it;s unlikely
to have been used.
However anyone designing around a chip that does cross boundaries 'properly', and then encountering
one that same-page-wrapped would quickly see problems. (e.g. when production changes supplier...)