CC1125: Frequency setting in CC1125

Hi Vikas,

To change the frequency you can follow this steps:

1. Make sure the radio is in the idle state.
   The frequency registers should not be modified while the frequency synthesizer is running, therefore it is necessary to verify that the radio is in idle state. You can send the SIDLE command strobe to force the radio to go into idle mode. If the radio is in Tx or Rx mode the commands will be interrupted.
   
   
2. Set the LO divider.
   This should only be done once since your frequency settings will be in the same band. For 410-480 band LO divider must be set to 8.
   To set the LO divider you need to write to the FSD_BANDSELECT bits in the FS_CFG register.
   
   
   
3. Calculate the FREQ registers values.
   The following formulas can be used to calculate FREQ value
   
   Assuming frequency offset is not used, FREQ = ((Frf * LO Divider) * 2^16) / Fxosc Where Frf = the desired RF frequency [Hz], LO divider = 8, and Fxosc = the crystal frequency [Hz]
   The calculated value must be written to FREQ2, FREQ1, and FREQ0 registers.
   
4. Turn on auto calibration when going from IDLE to RX or TX.
   Synthesizer calibration is required when a new RF frequency is used.
   To turn on auto calibration write 1 to the FS_AUTOCAL bits in SETTLING_CFG register. This should only be done once.