Calibration

This section describes, how the filter and PLL calibration algorithms are started manually. The filter calibration algorithm is done automatically, whenever a state change from the states P_ON or SLEEP to the state TRX_OFF occurs or a transceiver reset (see Reset) is performed. The PLL is calibrated during a state change from state TRX_OFF to any of the [PLL_ACTIVE] states. If these state changes does not occur during the normal operation of the radio transceiver frequently every 5 minutes, it is recommended to start it manually within this period. If the operating conditions of the radio transceiver (temperature, voltage) are nearly constant, the recalibration period may be increased.

Use Cases:

• PHY_CALIBRATE_FTN
• PHY_CALIBRATE_PLL

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PHY_CALIBRATE_FTN

Code example

    /* AT86RF231::[CONFIG] */
    trx_bit_write(SR_FTN_START, 1);
    delay(tTR16);

PHY_CALIBRATE_PLL

The calibration of the PLL center frequency (CF) and delay calibration unit (DCU) is initiated with the following sequence.

Note:

This calibration sequence can also be started in the state TX_ARET_ON.

Code example

    /* AT86RF231::PLL_ON */
    trx_bit_write(SR_PLL_DCU_START, 1);
    trx_bit_write(SR_PLL_CF_START, 1);
    delay(tTR21);

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