PM3_EXT_CLOCK_FREQ
feedback = (prescale * (1UL << postscale) * freq) / (2 * PM3_EXT_CLOCK_FREQ);
VCOlow = (2 * PM3_EXT_CLOCK_FREQ * feedback) / prescale;
feedback = (prescale * (1UL << postscale) * freq) / (2 * PM3_EXT_CLOCK_FREQ);
VCOhigh = (2 * PM3_EXT_CLOCK_FREQ * feedback) / prescale;
IntRef = PM3_EXT_CLOCK_FREQ / prescale;
feedback = (prescale * (1UL << postscale) * freq) / (2 * PM3_EXT_CLOCK_FREQ);
VCO = (2 * PM3_EXT_CLOCK_FREQ * feedback) / prescale;