EEPROM Data Search

[PICTRAIL]

Hi,
I would like to know how to search for a data in EEPROM without knowing the location.
I have an array of 6 char which i input through keypad. I want to search on my EEPROM if this data is available or not. Kindly give an idea on possible code system.

Thanks,
Ebby.

[aurora]

Assuming you store the 6 char in the first 6 address of your EEPROM;
and if all 6 char come in at the same time, just check the 6th character if it is a null value. For example, you pre-set all your EEPROM to a non-char (something that you know, i.e. 0xFE).

If the number of char is unknown, then you have to write a routine that check for the null value (i.e. 0xFE) and see where it is located. The search will start from EEPROM first address, until it found the null.

[shahrul]

You must know what is the expected data, then you check one-by-one address, compare is that the data.

But, I wonder, how do you don't know your data address? because you must program your EEPROM write. Why the data can be store in random address?

[robosang]

agreed with the rest, you must read and compare the data byte by byte because it can be anything if you have lost the address of it being stored.

Check the 1st byte which you expected and try to match it with 2nd byte until all 6 bytes matched. Else discard the data and search the 1st byte again.