14.2.2.3.4 RX_AACK_NOCLK – RX_AACK_ON without CLKM

If the AT86RF212B is listening for an incoming frame and the microcontroller is not running an application, the microcontroller can be powered down to decrease the total system power consumption. This special power-down scenario for systems running in clock synchronous mode is supported by the AT86RF212B using the states RX_AACK_ON_NOCLK and BUSY_RX_AACK_NOCLK, see Figure 14-26. They achieve the same functionality as the states RX_AACK_ON and BUSY_RX_AACK with pin 17 (CLKM) disabled.

The RX_AACK_NOCLK state is entered from RX_AACK_ON by a rising edge at pin 11 (SLP_TR). The return to RX_AACK_ON state automatically results either from the reception of a valid frame, indicated by interrupt IRQ_3 (TRX_END), or a falling edge on pin 11 (SLP_TR).

A received frame is considered valid if it passes frame filtering and has a correct FCS. If an ACK was requested, the radio transceiver enters BUSY_RX_AACK state and follows the procedure described in the RX_AACK_ON – Receive with Automatic ACK section.

After the RX_AACK transaction has been completed, the radio transceiver remains in RX_AACK_ON state. The AT86RF212B re-enters the RX_AACK_ON_NOCLK state only by the next rising edge on pin 11 (SLP_TR).

The timing and behavior, when CLKM is disabled or enabled, are described in the Sleep/Wake-up and Transmit Signal (SLP_TR) section.