NFCTagInitialise is failing since I2C read operation from system register on NFC is failing.

[Shruthi]

Hi,

Im trying to interface ST25DV04K-8pin with ESP32Wroom. I have initialized I2C communication on ESP as Master. 

Source files for ST25DV NFC - https://github.com/stm32duino/ST25DV/tree/master/src

NFCTagInitialise is failing as it is not reading the system Information at 0x17, 0x18-0x1f.

ESP - I2C driver returns error (-1). ESP is unable to write the target address to NFC chip (invalid address). Hence Read buffer is not loaded with the data from slave (NFC module)

[Shruthi]

I want to read data onto my master board(STM32F7) from NFC whenever external mobile device writes onto ST25DV. I think we must be reading this MB_ctrl_dyn registers for this. But Im unable to read of write from any of these registers.

[Rene Lenerve · Accepted solution]

Hi @Shruthi​,

To write configuration registers you need to open an i²C security session. To do that you have to present a password, by default the 64-bit password is 0 (refer to I2C_PWD access in the datasheet).

Did you open a security session before trying to write configuration registers?

Best regards.