This article describes how to evaluate ULPCD feature toghether with PN7642 EVK (OM27642EVK) and NFC Cockpit.
1// Disable DC-DC in EEPROM
OM27642EVK does not required any HW changes for ULPCD. User is only required to change the following settings in EEPROM (disable DC-DC converter).
Address: 0x0000 (Secure_Lib_Config)
Value: 0x21
2//Set required ULPCD settings in EEPROM
The default settings can be used as a starting point as such. The optimum threshold for OM27642EVK is between 5-10.
Below 5, user can observe higher occurrence of fake detection
Above 10, the detection range might drop significantly.
3// Perform "Reads HF Attenuator"
Once the required ULPCD settings is set (Guard times, Threshold....). Then User has to perform "Reads HF Attenuator". This will read and write the HF Attenuator value in the EEPROM at the address 0x63A (Secure_Lib_Config).
4//Enable that the RSSI value is calculated based on HF attenuator value
User is required to set most significant bit (7) to 1b. This will enable RSSI calculation based on the current HF attenuator value.
Example: If the HF Attenuator value is 0x0B, user has to write 0x8B in the eeprom field.
Note that if user reads the HF attenuator again, this step must be repeated.
Note: This has been updated in NFC Cockpit version 8.3.0. User needs to "check" the HF Attenuator check box.
5// Perform ULPCD Calibration and check RSSI Value
User can now perform the ULPCD Calibration and check the RSSI value by reading PCRM_ULPCD_STS register.
For OM27642EVK, the RSSI value for unloaded antenna is typically around 1500dec - 1550dec.
6//Enter ULPCD mode
User can enter the ULPCD mode. The board will be again connected once the load change is detected (e.g. NFC card or smarphone in the antenna proximity).
