ST25DV How to write EH_MODE register?

[MXliv.1]

Hi,

I have a suctom board with st25dv schip and i want to use EH for powering it. By default, EH_MODE is ON_DEMAND and I want to change it to ST25DV_EH_ACTIVE_AFTER_BOOT like as at on the devkit, but after writing using SMARTAG1_NFCTAG_WriteEHMode(SMARTAG1_NFCTAG_INSTANCE, ST25DV_EH_ACTIVE_AFTER_BOOT) command the value of the register doesn't changed. Datasheet says that I must use security mode for writing static config register, but how can I enter to this mode?

Thanks

[JL. Lebon · Accepted solution]

Hello,

In order to change the EH_MODE setting, you must first open the I2C security session.

This is done by presenting the I2C password.

For this, you can use the function SMARTAG1_NFCTAG_PresentI2CPassword().

By default, the I2C password is all 00 (8 bytes of 00)

After presenting the correct password, you can check if the security session is opened by using the function SMARTAG1_NFCTAG_ReadI2CSecuritySession_Dyn().

Then, if it ok, you can do the SMARTAG1_NFCTAG_WriteEHMode()

Best regards.

[davepatton]

I am using an ST25R3911B-DISCO board along with an STEVAL-SMARTAGB board and want to enable energy harvesting in the ST25DV64KC on this board.
Using the ST25R3911B Discovery GUI, it does not want to change the value of Config Register EH_MODE from 01 to 00.
I have also tried using the Android ST25 NFC Tap app.  This app says that it changed the value from 01 to 00 but if I read it again, it still shows a value of 01.
How can I permanently change the the EH_MODE to 00?