14.3.6.2 Configuration and Request

The CCA modes are configurable via the PHY_CC_CCA register.

When in Basic Operating Mode, a CCA request can be initiated manually by setting the CCA_REQUEST bit in the PHY_CC_CCA register (PHY_CC_CCA.CCA_REQUEST) to '1', if the AT86RF212B is in any RX state. The current channel status (CCA_STATUS) and the CCA completion status (CCA_DONE) are accessible through the TRX_STATUS register.

The end of a manually initiated CCA (eight symbol periods plus 12µs processing delay) is indicated by the interrupt IRQ_4 (CCA_ED_DONE).

The CCA_ED_THRES bits in the CCA_THRES register (CCA_THRES.CCA_ED_THRES) defines the receive power threshold of the “energy above threshold” algorithm. The threshold is calculated by:

P_{CCA_ED_THRES}[dBm] = RSSI_{BASE_VAL}[dBm] + 2.07[dB] x CCA_ED_THRES.

Any received power above this level is interpreted as a busy channel.

Note: It is not recommended to manually initiate a CCA measurement when using the Extended Operating Mode.