Hello,
For energy harvesting, there is two ways of enabling energy harvesting:
- Enabling EH automatically as soon as the RF field is present. This is done by writing static system configuration register EH_MODE to value 0x00. This register is non volatile and value will remains between power cycles.
- Enabling EH "on-demand" each time you need it. This is done by writing dynamic register EH_CTRL_Dyn to value 0x01. This register is volatile and value willbe reset to 0 during power cycles (so next boot, the EH will be disabled).
In ST25 NFC TAP app, you can activate EH by going in the left menu and select "Register Management" if you want to write the EH_MODE register (permanent EH) or select "Dyn Register Management" if you want to write into EH_CTRL_Dyn register (temporary EH).
Concerning write into a register:
- for static system configuration registers, you must first present a password to allow write access. If write register from I2C, you must first present the i2C password. If write from RF, you must first present the RF configuration password (Password 0). This may be your issue here.
- For dymanic registers, no need for a password.
All those points are clearly explained in the different documents publicly available on ST's web site (datasheet, application notes, etc.). Probably having a look at those docs would make your life easier.
Best regards.
