FC Calibration and CCA_MODE on CC1200

Hi everybody,


I have understand that the FC Calibration is mandatory at the startup of the CC1200. The value stored in FS_CHP, FS_VCO4 and FS_VCO2 are valid while the temperature gradient is less than 40 degrees.

We are wondering why the temperature has an influence on the PLL loop? Which parameters move with the temperature ? What happen physically on the PLL closed loop?

The second thing is, the CCA_MODE is setup as "100", the CC1200 is in RX and the RXOFF_MODE is in TX after RX. When I change the CCA_MODE to "000" and I received a good packet, the CC1200 issue an LBT before TX. The only way I found is to disable the LBT is to move in IDLE, change the CCA_MODE to "000" and strobe an STX. I can't change it without going in IDLE. Do you confirm that ?


Many thanks in advance

Gregory