Rf Calibration; Partial Calibration; Full Calibration; No Calibration - Espressif ESP32-S2 Programming Manual

Chapter 4. API Guides

4.24 RF calibration

ESP32-S2 supports three RF calibration methods during RF initialization:

1. Partial calibration

2. Full calibration

3. No calibration

4.24.1 Partial calibration
During RF initialization, the partial calibration method is used by default for RF calibration. It is done based on
the full calibration data which is stored in the NVS. To use this method, please go to menuconfig and enable
CONFIG_ESP_PHY_CALIBRATION_AND_DATA_STORAGE.
4.24.2 Full calibration
Full calibration is triggered in the follwing conditions:
1. NVS does not exist.
2. The NVS partition to store calibration data is erased.
3. Hardware MAC address is changed.
4. PHY library version is changed.
5. The RF calibration data loaded from the NVS partition is broken.
It takes about 100ms more than partial calibration.
the full calibration method. To switch to the full calibration method, go to menuconfig and disable
FIG_ESP_PHY_CALIBRATION_AND_DATA_STORAGE. If you use the default method of RF calibration, there are
two ways to add the function of triggering full calibration as a last-resort remedy.
1. Erase the NVS partition if you don't mind all of the data stored in the NVS partition is erased. That is indeed
the easiest way.
2. Call API esp_phy_erase_cal_data_in_nvs() before initializing WiFi and BT/BLE based on some
conditions (e.g. an option provided in some diagnostic mode). In this case, only phy namespace of the NVS
partition is erased.
4.24.3 No calibration
No calibration method is only used when the device wakes up from deep sleep.

4.24.4 PHY initialization data

The PHY initialization data is used for RF calibration. There are two ways to get the PHY initialization data.
One is the default
nents/esp_phy/esp32s2/include/phy_init_data.h.
It is embedded into the application binary after compiling and then stored into read-only memory (DROM). To use the
default initialization data, please go to menuconfig and disable CONFIG_ESP_PHY_INIT_DATA_IN_PARTITION.
Another is the initialization data which is stored in a partition. When using a custom partition table, make
sure that PHY data partition is included (type: data, subtype: phy). With default partition table, this is done
automatically. If initialization data is stored in a partition, it has to be flashed there, otherwise runtime er-
ror will occur. To switch to the initialization data stored in a partition, go to menuconfig and enable
FIG_ESP_PHY_INIT_DATA_IN_PARTITION.
Espressif Systems
initialization data which
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If boot duration is not critical, it is suggested to use
is located in
CON-
the header file compo-
CON-
Release v4.4