SWRS045F January 2006 – November 2018 CC1021
PRODUCTION DATA.
In synchronous mode, the DCLK pin on the CC1021 device can also be used to give an interrupt signal to the microcontroller when the RSSI level exceeds a certain threshold (carrier sense threshold). This function can be used to wake or interrupt the microcontroller when a strong signal is received.
Gating the DCLK signal with the carrier sense signal makes the interrupt signal.
This function should only be used in receive mode and is enabled by setting DCLK_CS = 1 in the INTERFACE register.
The DCLK signal is always logic high unless carrier sense is indicated. When carrier sense is indicated the DCLK starts running. When gating the DCLK signal with the carrier sense signal at least 2 dummy bits should be added after the data payload in TX mode. The reason being that the carrier sense signal is generated earlier in the receive chain (that is, before the demodulator), causing it to be updated 2 bits before the corresponding data is available on the DIO pin.
In transmit mode, DCLK_CS must be set to 0. Refer to CC1021 Errata Note 001, located in the CC1021 product folder.