rfm69hcw frequency calculator

Datasheet

.
FXOSC		| always 32 Mhz	| Crystal oscillator frequency	| int value
FSTEP		| always 61 hz	| FSTEP = FXOSC / ( 2 ^ 19 )	| int value
.
Reg0		| RegFrfMsb (0x07)	| MSB of the RF carrier frequency	| 8-bit hex value
Reg1		| RegFrfMid (0x08)	| Middle byte of the RF carrier frequency	| 8-bit hex value
Reg2		| RegFrfLsb (0x09)	| LSB of the RF carrier frequency	| 8-bit hex value
.
	Frf = Fstep ⋅ Frf(23;0)

Calculate

Reset

/*****************************************************************/
#include
#include
#include

#define FXOSC 32000000
// #define FSTEPdiv 524288

uint32_t rfm_freq(uint8_t reg0, uint8_t reg1, uint8_t reg2)
{
 uint8_t FSTEP;

 uint32_t FSTEPdiv, RegsBigEndian, frequency;

 FSTEPdiv = pow(2,19);
 FSTEP = FXOSC / FSTEPdiv;

 RegsBigEndian = (reg0 << 16) | (reg1 << 8) | reg2;

 frequency = FSTEP * RegsBigEndian;

 return frequency;
}

void main(void)
{
 uint8_t reg0, reg1, reg2;

 // 433.92 MHz
 reg0 = 0x6C;
 reg1 = 0x5C;
 reg2 = 0xA0;

 printf("%d\n", rfm_freq(reg0, reg1, reg2));
}
/*****************************************************************/