My EEPROM is write protected. How can i disable the password that has been implemented before?

[KUMAR SAURABH]

Posted on September 27, 2017 at 07:16

My EEPROM is write protected. How can i disable the password that has been implemented before?

[Thomas Q.]

Posted on September 28, 2017 at 09:26

Hello,

Can you please confirm which product you are refering to : is it the

http://www.st.com/content/st_com/en/products/nfc/st25-nfc-rfid-tags-readers/st25-nfc-rfid-tags/st25ta-series-nfc-tags.html?querycriteria=productId=SS1826

or the

http://www.st.com/content/st_com/en/products/nfc/st25-nfc-rfid-tags-readers/st25-dynamic-nfc-tags/m24sr-series-dynamic-nfc-tags.html?querycriteria=productId=SS1812

?

Best regards

[KUMAR SAURABH]

Posted on September 28, 2017 at 11:48

It's M24SR

[JP Miller]

Posted on September 28, 2017 at 13:58

Hello Kumar,

The password can be disabled using the 'Disable Verification Requirement' command of M24SR. for that the write password has to be presented prior to sending the 'Disable Verification Requirement' .

The section 'Unlocking an NDEF file' of the M24SR datasheets explains how. It is extracted below for your convenience:

The RF or I²C host executes this procedure to unlock an NDEF file which has been locked previously.

1.Select the NDEF Tag Application

2. Select the NDEF file

3. Verify the NDEF file Write password or the I²C password by using the Verify command

4. Unlock the NDEF file by sending the Disable verification command.

Have a good day.

Regards

[KUMAR SAURABH]

Posted on October 05, 2017 at 11:30

I have forgot the 'write password' that i had used before. How can i disable or recover the password? 

Also, Is there is process to do hard reset in M24SR?

[JP Miller · Accepted solution]

Posted on January 22, 2018 at 09:37

Dear Customer,

it is not possible to reset a password that has been written before for security reasons.

Hard reset of data that is not written in non volatile memory can be achieved with VCC off and RF field being off.

Have a good day.

Regards