X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?a=blobdiff_plain;f=firmware%2Fadc.c;h=fa0782c4248c6ee67917901cc1340dedfefea087;hb=ee55592455c9628ca21142449d4b5918a59151fe;hp=d0ee1c40f3377f17e40bd1f7662d662f72f8034f;hpb=5090774fd8ca593d3b247b099b3b6a40e837475e;p=bike-lights.git

diff --git a/firmware/adc.c b/firmware/adc.c
index d0ee1c4..fa0782c 100644
--- a/firmware/adc.c
+++ b/firmware/adc.c
@@ -12,12 +12,11 @@ volatile static unsigned char current_adc;
 static uint16_t adc_sum;
 static unsigned char sum_shift;
 static unsigned char adc_vals;
-static uint16_t adc1_gain20_offset_x16;
+#define ADC1_GAIN20_OFFSET_SHIFT	6
+static uint16_t adc1_gain20_offset;
 
 static void inline setup_mux(unsigned char n)
 {
-	ADCSRA |= _BV(ADEN); // enable ADC
-
 	/* ADC numbering: PWM LEDs first, then ambient light sensor, battery sensor */
 	switch (n) {
 	case 0: // pwmled 1: 1.1V, ADC0,1 (PA0,1), gain 20
@@ -30,7 +29,7 @@ static void inline setup_mux(unsigned char n)
 		break;
 	case 2: // pwmled 3: 1.1V, ADC4 (PA5), single-ended
 		ADMUX = _BV(REFS1) | _BV(MUX2);
-		sum_shift = 2; // 4 measurements
+		sum_shift = 3; // 8 measurements
 		break;
 	case 3: // ambient light: 1.1V, ADC5 (PA6), single-ended
 		ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX0);
@@ -42,7 +41,7 @@ static void inline setup_mux(unsigned char n)
 		break;
 	case 5: // gain stage offset: 1.1V, ADC1,1, gain 20
 		ADMUX = _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX0);
-		sum_shift = 3; // 8 measurements
+		sum_shift = 0; // 1 measurement
 		break;
 	}
 
@@ -87,21 +86,20 @@ void init_adc()
 		;
 	ADCSRA |= _BV(ADIF); // clear the IRQ flag
 
-	adc1_gain20_offset_x16 = 0;
+	adc1_gain20_offset = 0;
 
-	for (i = 0; i < 16; i++) {
+	for (i = 0; i < (1 << ADC1_GAIN20_OFFSET_SHIFT); i++) {
 		ADCSRA |= _BV(ADSC);
 
 		while ((ADCSRA & _BV(ADIF)) == 0)
 			;
-		adc1_gain20_offset_x16 += ADCW;
+		adc1_gain20_offset += ADCW
+			- (adc1_gain20_offset >> ADC1_GAIN20_OFFSET_SHIFT);
 
 		ADCSRA |= _BV(ADIF); // clear the IRQ flag
 	}
 
 	ADCSRA |= _BV(ADIE); // enable IRQ
-
-	ADCSRA &= ~_BV(ADEN); // disable until needed
 }
 
 void susp_adc()
@@ -116,8 +114,6 @@ ISR(ADC_vect) { // IRQ handler
 	if (adc_vals)
 		// start the next conversion immediately
 		ADCSRA |= _BV(ADSC);
-	else
-		ADCSRA &= ~_BV(ADEN); // the last one, disable ADC
 
 	if (adc_vals < (1 << sum_shift))
 		 // drop the first conversion, use all others
@@ -134,18 +130,19 @@ ISR(ADC_vect) { // IRQ handler
 
 	if (current_adc == ADC1_GAIN20) {
 		// running average
-		adc1_gain20_offset_x16 += adcval
-			- (adc1_gain20_offset_x16 >> 4);
+		adc1_gain20_offset += adcval
+			- (adc1_gain20_offset >> ADC1_GAIN20_OFFSET_SHIFT);
 	} else if (current_adc == 0 || current_adc == 1) {
-		uint16_t offset = adc1_gain20_offset_x16 >> 4;
-		if (adcval >= offset)
-			adcval -= offset;
+		uint16_t offset = adc1_gain20_offset
+			>> (ADC1_GAIN20_OFFSET_SHIFT - sum_shift);
+		if (adc_sum > offset)
+			adc_sum -= offset;
 		else
-			adcval = 0;
+			adc_sum = 0;
 	}
 
 	if (current_adc < N_PWMLEDS)
-		pwmled_adc(current_adc, adcval);
+		pwmled_adc(current_adc, adc_sum);
 	if (current_adc == AMBIENT_ADC)
 		ambient_adc(adcval);
 	if (current_adc == BATTERY_ADC)
@@ -158,5 +155,9 @@ 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
 }