X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?p=bike-lights.git;a=blobdiff_plain;f=firmware%2Fadc.c;h=3fdbe3262f3d6467364cd1a73063abd0d3be75e7;hp=70c2aa1adca1a95958fc02e992354b2345aeaaff;hb=HEAD;hpb=541892c2955660bdd068dc7bc0a2611592f408d7

diff --git a/firmware/adc.c b/firmware/adc.c
index 70c2aa1..2bca0cf 100644
--- a/firmware/adc.c
+++ b/firmware/adc.c
@@ -3,11 +3,14 @@
 
 #include "lights.h"
 
-#define AMBIENT_ADC N_PWMLEDS
-#define BATTERY_ADC (N_PWMLEDS + 1)
-#define ADC1_GAIN20 (N_PWMLEDS + 2)
-#define BUTTON_ADC  (N_PWMLEDS + 3)
-#define ZERO_ADC    (N_PWMLEDS + 4)
+// pwmleds are measured continuously (when active)
+#define AMBIENT_ADC N_PWMLEDS		// measured every jiffy (16 Hz)
+#define BUTTON_ADC  (N_PWMLEDS + 1)	// measured every jiffy (16 Hz)
+#define FIRST_16HZ_ADC	BUTTON_ADC
+#define BATTERY_ADC (N_PWMLEDS + 2)	// once per second
+#define ADC1_GAIN20 (N_PWMLEDS + 3)	// once per second
+#define FIRST_1S_ADC	ADC1_GAIN20
+#define ZERO_ADC    (N_PWMLEDS + 4)	// must be last
 
 #define NUM_ADCS	ZERO_ADC
 
@@ -20,12 +23,14 @@ struct {
 	{ 0, 1, PWMLED_ADC_SHIFT },	// pwmled 2
 	{ 0, 1, PWMLED_ADC_SHIFT },	// pwmled 3
 	{ 0, 1, AMBIENT_ADC_SHIFT },	// ambient
+	{ 0, 1, 0 },			// buttons
 	{ 0, 1, 0 },			// battery
 	{ 0, 1, 0 },			// gain20
-	{ 0, 1, 0 },			// buttons
 };
 
-volatile static unsigned char current_adc;
+volatile unsigned char adc_is_on;
+
+volatile static unsigned char current_adc, slow_adcs_wanted;
 static uint16_t adc_sum, zero_count, drop_count, read_count, n_reads_log;
 #define ADC1_GAIN20_OFFSET_SHIFT	6
 static uint16_t adc1_gain20_offset;
@@ -47,16 +52,16 @@ static void setup_mux(unsigned char n)
 	case AMBIENT_ADC: // ambient light: 1.1V, ADC5 (PA6), single-ended
 		ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX0);
 		break;
+	case BUTTON_ADC: // buttons: 1.1V, ADC3, single-ended
+		PORTA |= _BV(PA3); // +5V to the voltage splitter
+		ADMUX = _BV(REFS1) | _BV(MUX1) | _BV(MUX0);
+		break;
 	case BATTERY_ADC: // batt voltage: 1.1V, ADC6 (PA7), single-ended
 		ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX1);
 		break;
 	case ADC1_GAIN20: // gain stage offset: 1.1V, ADC1,1, gain 20
 		ADMUX = _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX0);
 		break;
-	case BUTTON_ADC: // buttons: 1.1V, ADC3, single-ended
-		PORTA |= _BV(PA3); // +5V to the voltage splitter
-		ADMUX = _BV(REFS1) | _BV(MUX1) | _BV(MUX0);
-		break;
 	case ZERO_ADC: // zero: 1.1V, ADC1 (PA1), single-ended
 		ADMUX = _BV(REFS1) | _BV(MUX0);
 		break;
@@ -65,14 +70,31 @@ static void setup_mux(unsigned char n)
 
 static void start_next_adc()
 {
-	if (current_adc > 0) {
+	if (slow_adcs_wanted) {
+		current_adc = slow_adcs_wanted;
+		slow_adcs_wanted = 0;
+		goto found;
+	}
+
+	if (current_adc > N_PWMLEDS) {
 		current_adc--;
-	} else {
-		// TODO: kick the watchdog here.
-		current_adc = NUM_ADCS;
+		goto found;
+	}
+
+	if (!TIMER1_IS_ON()) {
+		adc_is_on = 0;
 		return;
 	}
 
+	do {
+		if (!current_adc)
+			current_adc = N_PWMLEDS;
+		--current_adc;
+	} while (!PWM_IS_ON(current_adc));
+
+found:
+	adc_is_on = 1;
+
 	adc_sum = 0;
 	// we use the last iteration of zero_count to set up the MUX
 	// to its final destination, hence the "1 +" below:
@@ -98,12 +120,17 @@ static void start_next_adc()
 	ADCSRA |= _BV(ADSC);
 }
 
-void timer_start_adcs()
+void timer_start_slow_adcs()
 {
-	if (current_adc == NUM_ADCS) // Don't start if in progress
+	if ((jiffies & 0x000F) == 0) {
+		slow_adcs_wanted = FIRST_1S_ADC;
+	} else {
+		slow_adcs_wanted = FIRST_16HZ_ADC;
+	}
+
+	if (!adc_is_on) {
 		start_next_adc();
-	else
-		log_byte(0x99); // overrun
+	}
 }
 
 /*
@@ -129,7 +156,9 @@ static uint16_t read_adc_sync()
 void init_adc()
 {
 	unsigned char i;
-	current_adc = NUM_ADCS;
+	current_adc = 0;
+	adc_is_on = 1;
+	slow_adcs_wanted = FIRST_1S_ADC;
 
 	ADCSRA = _BV(ADEN)			// enable
 		| _BV(ADPS1) | _BV(ADPS0)	// CLK/8 = 125 kHz
@@ -175,6 +204,18 @@ static void adc1_gain20_adc(uint16_t adcsum)
 ISR(ADC_vect) { // IRQ handler
 	uint16_t adcval = ADCW;
 
+	/*
+	 * After the timer interrupt, drop the current reading.
+	 * We may have changed the PWM outputs, so the value is
+	 * probably useless anyway.
+	 * FIXME: possible race condition - we should make an explicit
+	 * notification inside the timer IRQ handler.
+	 */
+	if (slow_adcs_wanted) {
+		start_next_adc();
+		return;
+	}
+
 	if (zero_count) {
 		if (zero_count > 1) {
 			ADCSRA |= _BV(ADSC);
@@ -197,6 +238,7 @@ ISR(ADC_vect) { // IRQ handler
 		ADCSRA |= _BV(ADSC);
 		adc_sum += adcval;
 		read_count--;
+		pwm_timer();
 		return;
 	}
 
@@ -225,12 +267,12 @@ ISR(ADC_vect) { // IRQ handler
 	case AMBIENT_ADC:
 		ambient_adc(adc_sum);
 		break;
-	case BATTERY_ADC:
-		battery_adc(adc_sum);
-		break;
 	case BUTTON_ADC:
 		button_adc(adc_sum);
 		break;
+	case BATTERY_ADC:
+		battery_adc(adc_sum);
+		break;
 	case ADC1_GAIN20:
 		adc1_gain20_adc(adcval);
 		break;