On ST25DV after writing to FTM buffer cannot write to EEPROM via I2C.

[NKern.1]

app_twi_perform() returns 0x03 == NRF_ERROR_INTERNAL.

Reset board with button does not help.

After Power Cycle can update EEPROM successfully.

Accessing FTM buffer with proprietary smartphone app.

[JL. Lebon · Accepted solution]

Hello,

Sorry, it is a little bit difficult to help with so few information...

Nevertheless, I think your problem may be that you try to write into EEPROM with the FTM activated.

As explained in the ST25DV datasheet (https://www.st.com/resource/en/datasheet/st25dv04k.pdf) chapter "5.1.2 Fast transfer mode usage" in the "caution" paragraph of page 25, it is not possible to write into EEPROM if FTM is activated (meaning of bit 0 of MB_CTRL_Dyn register value is 1).

A "power on/off cycle" reset the MB_CTRL_Dyn register, thus deactivating the FTM, which can explain why you can write EEPROM after the ON/OFF cycle. Not sure about the "reset board" since I don't know what board you are talking about.

So, my suggestion is to try to disable FTM before trying to write into EEPROM.

Best regards.

[NKern.1]

Thank you, JL.

That indeed was the case. Appreciate your advice and great customer support.

EDIT. Sometimes it still crashes when setting MB_CTRL_Dyn register.