switch (n) {
case 0: // pwmled 1: 1.1V, ADC0,1 (PA0,1), gain 20
ADMUX = _BV(REFS1) | _BV(MUX3) | _BV(MUX1) | _BV(MUX0);
- sum_shift = 3; // 8 measurements
+ sum_shift = PWMLED_ADC_SHIFT;
break;
case 1: // pwmled 2: 1.1V, ADC2,1 (PA2,1), gain 20
ADMUX = _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
- sum_shift = 3; // 8 measurements
+ sum_shift = PWMLED_ADC_SHIFT;
break;
case 2: // pwmled 3: 1.1V, ADC4 (PA5), single-ended
ADMUX = _BV(REFS1) | _BV(MUX2);
- sum_shift = 3; // 8 measurements
+ sum_shift = PWMLED_ADC_SHIFT;
break;
case 3: // ambient light: 1.1V, ADC5 (PA6), single-ended
ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX0);
static void start_next_adc()
{
- if (current_adc > 0) {
+ if (current_adc > 0)
current_adc--;
- // set up mux, start one-shot conversion
- setup_mux(current_adc);
- ADCSRA |= _BV(ADSC);
- } else {
- current_adc = NUM_ADCS;
+ else
// TODO: kick the watchdog here.
- }
+ current_adc = NUM_ADCS-1;
+
+ // set up mux, start one-shot conversion
+ setup_mux(current_adc);
+ ADCSRA |= _BV(ADSC);
+}
+
+/*
+ * Single synchronous ADC conversion.
+ * Has to be called with IRQs disabled (or with the ADC IRQ disabled).
+ */
+static uint16_t read_adc_sync()
+{
+ uint16_t rv;
+
+ ADCSRA |= _BV(ADSC); // start the conversion
+
+ // wait for the conversion to finish
+ while((ADCSRA & _BV(ADIF)) == 0)
+ ;
+
+ rv = ADCW;
+ ADCSRA |= _BV(ADIF); // clear the IRQ flag
+
+ return rv;
}
void init_adc()
// 1.1V, ADC1,1, gain 20
ADMUX = _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX0);
- ADCSRA |= _BV(ADSC);
/* Do first conversion and drop the result */
- while ((ADCSRA & _BV(ADIF)) == 0)
- ;
- ADCSRA |= _BV(ADIF); // clear the IRQ flag
+ read_adc_sync();
adc1_gain20_offset = 0;
for (i = 0; i < (1 << ADC1_GAIN20_OFFSET_SHIFT); i++) {
- ADCSRA |= _BV(ADSC);
-
- while ((ADCSRA & _BV(ADIF)) == 0)
- ;
- adc1_gain20_offset += ADCW
+ adc1_gain20_offset += read_adc_sync()
- (adc1_gain20_offset >> ADC1_GAIN20_OFFSET_SHIFT);
-
- ADCSRA |= _BV(ADIF); // clear the IRQ flag
}
ADCSRA |= _BV(ADIE); // enable IRQ
+
+ start_next_adc();
}
void susp_adc()
start_next_adc();
}
-void timer_start_adcs()
-{
- if (current_adc == NUM_ADCS) // Don't start if in progress
- start_next_adc();
-#if 0
- else
- log_byte(0x99);
-#endif
-}
-