ST25DV64 Read and Write From Mobile

Ranjan · ‎2024-07-26

Hello, I am implementing an application in which smartphone users can read/write multiple NDEF records from ST25DV64K tag. My question is how I know the EEPROM address of tag to read that data from microcontroller?

JL. Lebon · ‎2024-07-29

Hello,

If re asking for the I2C address of the ST25DV64K, it is explained in the datasheet in the chapter "6.3 Device addressing"

If you are asking for the location of the NDEF message in the EEPROM memory of the tag, then the location NDEF in a type 5 tag memory is specified by the NFC forum specification.

In EEPROM memory, you always have the CC File at the beginning of the memory, coded on 1 or 2 blocks (probably 2 blocks in your case as you are using a ST25DV64K). The NDEF file is right after the CC File, meaning at blocks 2 or 3. A block is 4 Bytes. So, to access the NDEF file from I2C, you need to access address 2*4=8 or 3*4=12.

Best regards.

View solution in original post

JL. Lebon · ‎2024-07-29

Hello,

If re asking for the I2C address of the ST25DV64K, it is explained in the datasheet in the chapter "6.3 Device addressing"

If you are asking for the location of the NDEF message in the EEPROM memory of the tag, then the location NDEF in a type 5 tag memory is specified by the NFC forum specification.

In EEPROM memory, you always have the CC File at the beginning of the memory, coded on 1 or 2 blocks (probably 2 blocks in your case as you are using a ST25DV64K). The NDEF file is right after the CC File, meaning at blocks 2 or 3. A block is 4 Bytes. So, to access the NDEF file from I2C, you need to access address 2*4=8 or 3*4=12.

Best regards.