X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?a=blobdiff_plain;f=firmware%2Fadc.c;h=0ec32af77c0a54db8bbc4b0f8a6ac8476086e15f;hb=5d0f6ceb47eed2282aeb11eb57eebc390add234e;hp=fa0782c4248c6ee67917901cc1340dedfefea087;hpb=295d6d70b233e295c5080c998b9f54306c1170cf;p=bike-lights.git

diff --git a/firmware/adc.c b/firmware/adc.c
index fa0782c..0ec32af 100644
--- a/firmware/adc.c
+++ b/firmware/adc.c
@@ -21,19 +21,19 @@ static void inline setup_mux(unsigned char n)
 	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);
-		sum_shift = 0; // 1 measurement
+		sum_shift = 3; // 3 measurements
 		break;
 	case 4: // batt voltage: 1.1V, ADC6 (PA7), single-ended
 		ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX1);
@@ -51,15 +51,35 @@ static void inline setup_mux(unsigned char n)
 
 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()
@@ -79,27 +99,20 @@ 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()
@@ -144,20 +157,10 @@ ISR(ADC_vect) { // IRQ handler
 	if (current_adc < N_PWMLEDS)
 		pwmled_adc(current_adc, adc_sum);
 	if (current_adc == AMBIENT_ADC)
-		ambient_adc(adcval);
+		ambient_adc(adc_sum);
 	if (current_adc == BATTERY_ADC)
 		battery_adc(adcval);
 	
 	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
-}
-