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=c6b113d4932cb538768fb8f94674d53af34a2483;hb=HEAD;hpb=5d0ab95bb20a304693c1e0ec6c7900b7090d03e2

diff --git a/firmware/adc.c b/firmware/adc.c
index c6b113d..2bca0cf 100644
--- a/firmware/adc.c
+++ b/firmware/adc.c
@@ -6,8 +6,10 @@
 // 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
@@ -26,7 +28,9 @@ struct {
 	{ 0, 1, 0 },			// gain20
 };
 
-volatile static unsigned char current_adc, current_slow_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;
@@ -66,25 +70,30 @@ static void setup_mux(unsigned char n)
 
 static void start_next_adc()
 {
-	if (current_adc == 0) {
-		if (current_slow_adc > N_PWMLEDS) {
-			// read one of the non-PWMLED ADCs
-			current_adc = --current_slow_adc;
-		} else {
-			// no more non-PWMLEDs to do, start with PWMLEDs
-			current_adc = N_PWMLEDS-1;
-		}
-	} else if (current_adc >= N_PWMLEDS) {
-		// one of the non-PWMLED ADCs just finished, skip to PWMLEDs.
-		current_adc = N_PWMLEDS-1;
-	} else {
-		// next PWMLED
+	if (slow_adcs_wanted) {
+		current_adc = slow_adcs_wanted;
+		slow_adcs_wanted = 0;
+		goto found;
+	}
+
+	if (current_adc > N_PWMLEDS) {
 		current_adc--;
+		goto found;
+	}
+
+	if (!TIMER1_IS_ON()) {
+		adc_is_on = 0;
+		return;
 	}
 
-#if 0
-	log_byte(0x90 + current_adc); // debug ADC switching
-#endif
+	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
@@ -113,11 +122,14 @@ static void start_next_adc()
 
 void timer_start_slow_adcs()
 {
-	if (current_slow_adc > N_PWMLEDS) { // Don't start if in progress
-		log_byte(0x80 + current_slow_adc);
+	if ((jiffies & 0x000F) == 0) {
+		slow_adcs_wanted = FIRST_1S_ADC;
 	} else {
-		current_slow_adc = NUM_ADCS;
-		// TODO: kick the watchdog here
+		slow_adcs_wanted = FIRST_16HZ_ADC;
+	}
+
+	if (!adc_is_on) {
+		start_next_adc();
 	}
 }
 
@@ -144,8 +156,9 @@ static uint16_t read_adc_sync()
 void init_adc()
 {
 	unsigned char i;
-	current_slow_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
@@ -191,6 +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);
@@ -213,6 +238,7 @@ ISR(ADC_vect) { // IRQ handler
 		ADCSRA |= _BV(ADSC);
 		adc_sum += adcval;
 		read_count--;
+		pwm_timer();
 		return;
 	}