hi sir,
we have a problem on calculating rf radio frequency from the FREQ [2:0] registers,
this is my code for read rf frequency,,
float readCC112xRfFreq()
{
union
{
unsigned long int longval;
unsigned char charval[4];
}Lv;
cc112xSpiReadReg(CC112X_FREQ2,&Lv.charval[2],1);
cc112xSpiReadReg(CC112X_FREQ1,&Lv.charval[1],1);
cc112xSpiReadReg(CC112X_FREQ0,&Lv.charval[0],1);
Lv.charval[3]=0;
float fvco= (float) (((float) Lv.longval/(float) TWO_POW_16)*RF_FXOSC);
float rfFreq= fvco/(float)RF_LO_DIVIDER_868;
return rfFreq;
}
/****************************************************************************
the freq [2:0] reg write value
Write_cc112x(CC112X_FREQ2 ,0x56 ); //Frequency Configuration [23:16]*/
Write_cc112x(CC112X_FREQ1 ,0xFE ); //Frequency Configuration [15:8]*/
Write_cc112x(CC112X_FREQ0 ,0x00 ); //Frequency Configuration [15:8]*/FREQ0
***********************************************************************************/
i can able to read back the above freq[2:0] values 56,FE,00
but the function float readCC112xRfFreq() give the wrong value ,then i debugged
the value of Lv.longval is wrong not he expected value for 869.2224Mhz
i had worked out on excel sheet in the attachment
