uint16_t analog_get(index_t index)
{
if (IX_ANALOG(1) <= index && index <= IX_ANALOG(USER_CT_ANALOG) && NUM_ANALOG_VALID(USER_CT_ANALOG)) {
/* Read ADC (0b10000111 = 0x87). */
uint8_t chan = 0x87 | (IX_ANALOG_INV(index) << 3);
adc_setchannel(chan);
delay10tcy(5); /* Wait for capacitor to charge */
adc_conv();
while(adc_busy());
return adc_read();
} else {
WARN_IX(index);
return 0;
}
}
/*
* init ports
*/
void audioget_init(void) {
//init adc
adc_setchannel(AUDIOGET_INPUTCHANNEL);
adc_init();
#if AUDIOGET_USETIMER == 1
//init timer
ICR1 = TIMER1_ICR1; //ICR1
TCCR1A = (1 << WGM11); //fast pwm mode
TCCR1B = (1 << WGM13) | (1 << WGM12);
TCCR1B |= TIMER1_PRESCALER; //prescaler
TIMSK |= (1<<TOIE1); //enable timer1
#endif
//enable interrupt
sei();
}
/*
* get rms value from audio signal
* signal must be biased to ADVREF voltage / 2
*/
int16_t audioget_getrmsval(void) {
static int16_t retval = 0;
int16_t getval = 0;
#if AUDIOGET_USETIMER == 1
while(!audioget_adccollected);
audioget_adccollected = 1;
#endif
#if AUDIOGET_USETIMER == 0
#if AUDIOGET_DYNAMICBIAS == 1
int16_t biasadc = 0;
int16_t biasadcmin = 1024;
int16_t biasadcmax = 0;
#endif
#endif
//get value using avarage method
//---------------------------------------
int32_t rmssquaresum = 0;
int16_t adc_raw = 0;
#if AUDIOGET_USETIMER == 0
adc_setchannel(AUDIOGET_INPUTCHANNEL);
#endif
//root mean square to measure value
uint8_t i = 0;
for(i=0; i<AUDIOGET_AVARAGESAMPLES; i++) {
#if AUDIOGET_USETIMER == 1
adc_raw = audioget_adcsamples[i];
#else
adc_raw = adc_readsel();
#if AUDIOGET_DYNAMICBIAS == 1
if(adc_raw < biasadcmin)
biasadcmin = adc_raw;
if(adc_raw > biasadcmax)
biasadcmax = adc_raw;
biasadc = (biasadcmin + (biasadcmax-biasadcmin)/2);
adc_raw = adc_raw - biasadc;
#else
adc_raw = adc_raw - AUDIOGET_BIASZERORAW;
#endif
#endif
rmssquaresum += ((int32_t)adc_raw * (int32_t)adc_raw);
}
//root
getval = sqrt(rmssquaresum/AUDIOGET_AVARAGESAMPLES)-AUDIOGET_AVARAGECORRECTION;
//smooth filter
retval = ((int32_t)(64-AUDIOGET_SMOOTHFILTERVAL)*retval+(int32_t)AUDIOGET_SMOOTHFILTERVAL*getval)>>6;
if(retval<0)
retval = 0;
#if AUDIOGET_USETIMER == 1
audioget_adccollected = 0;
#endif
return retval;
}
