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=ef714777011f1af24d171bb44cdd0d6461ac6b0e;hp=f5d846f2b21d0340bd8f3411a1d214db5ae04583;hb=c30006aaf666f7cff3a6ab949c613c2f8cc6163b;hpb=dfdde30a343b7da032bea880b0677b49ff0e5d8a

diff --git a/firmware/adc.c b/firmware/adc.c
index f5d846f..ef71477 100644
--- a/firmware/adc.c
+++ b/firmware/adc.c
@@ -6,66 +6,145 @@
 #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)
 
-#define NUM_ADCS 6
-volatile static unsigned char current_adc;
-static uint16_t adc_sum;
-static unsigned char sum_shift;
-static unsigned char adc_vals;
+#define NUM_ADCS	ZERO_ADC
+
+struct {
+	unsigned char read_zero_log : 2;
+	unsigned char read_drop_log : 2;
+	unsigned char read_keep_log : 4;
+} adc_params[NUM_ADCS] = {
+	{ 0, 1, PWMLED_ADC_SHIFT },	// pwmled 1
+	{ 0, 1, PWMLED_ADC_SHIFT },	// pwmled 2
+	{ 0, 1, PWMLED_ADC_SHIFT },	// pwmled 3
+	{ 0, 1, AMBIENT_ADC_SHIFT },	// ambient
+	{ 0, 1, 0 },			// battery
+	{ 0, 1, 0 },			// gain20
+	{ 0, 1, 0 },			// buttons
+};
+
+volatile static unsigned char current_adc, current_slow_adc;
+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;
 
-static void inline setup_mux(unsigned char n)
+
+static void setup_mux(unsigned char n)
 {
-	/* ADC numbering: PWM LEDs first, then ambient light sensor, battery sensor */
+	/* ADC numbering: PWM LEDs first, then others, zero at the end */
 	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 = 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 = PWMLED_ADC_SHIFT;
 		break;
 	case 2: // pwmled 3: 1.1V, ADC4 (PA5), single-ended
 		ADMUX = _BV(REFS1) | _BV(MUX2);
-		sum_shift = PWMLED_ADC_SHIFT;
 		break;
-	case 3: // ambient light: 1.1V, ADC5 (PA6), single-ended
+	case AMBIENT_ADC: // ambient light: 1.1V, ADC5 (PA6), single-ended
 		ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX0);
-		sum_shift = 0; // 1 measurement
 		break;
-	case 4: // batt voltage: 1.1V, ADC6 (PA7), single-ended
+	case BATTERY_ADC: // batt voltage: 1.1V, ADC6 (PA7), single-ended
 		ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX1);
-		sum_shift = 0; // 1 measurement
 		break;
-	case 5: // gain stage offset: 1.1V, ADC1,1, gain 20
+	case ADC1_GAIN20: // gain stage offset: 1.1V, ADC1,1, gain 20
 		ADMUX = _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX0);
-		sum_shift = 0; // 1 measurement
+		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;
 	}
-
-	adc_sum = 0;
-	adc_vals = 1 << sum_shift;
 }
 
 static void start_next_adc()
 {
-	if (current_adc > 0)
+	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
 		current_adc--;
+	}
+
+#if 0
+	log_byte(0x90 + current_adc); // debug ADC switching
+#endif
+
+	adc_sum = 0;
+	// we use the last iteration of zero_count to set up the MUX
+	// to its final destination, hence the "1 +" below:
+	if (adc_params[current_adc].read_zero_log)
+		zero_count = 1 + (1 << (adc_params[current_adc].read_zero_log-1));
 	else
-		// TODO: kick the watchdog here.
-		current_adc = NUM_ADCS-1;
+		zero_count = 1;
+
+	if (adc_params[current_adc].read_drop_log)
+		drop_count = 1 << (adc_params[current_adc].read_drop_log - 1);
+	else
+		drop_count = 0;
+
+	read_count = 1 << adc_params[current_adc].read_keep_log;
+	n_reads_log = adc_params[current_adc].read_keep_log;
 
 	// set up mux, start one-shot conversion
-	setup_mux(current_adc);
+	if (zero_count > 1)
+		setup_mux(ZERO_ADC);
+	else
+		setup_mux(current_adc);
+
 	ADCSRA |= _BV(ADSC);
 }
 
+void timer_start_slow_adcs()
+{
+	if (current_slow_adc > N_PWMLEDS) { // Don't start if in progress
+		log_byte(0x80 + current_slow_adc);
+	} else {
+		current_slow_adc = NUM_ADCS;
+		// TODO: kick the watchdog here
+	}
+}
+
+/*
+ * 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()
 {
 	unsigned char i;
-	current_adc = NUM_ADCS;
+	current_slow_adc = NUM_ADCS;
+	current_adc = 0;
 
 	ADCSRA = _BV(ADEN)			// enable
 		| _BV(ADPS1) | _BV(ADPS0)	// CLK/8 = 125 kHz
@@ -74,29 +153,20 @@ void init_adc()
 	// ADCSRB |= _BV(GSEL); // gain 8 or 32
 
 	// Disable digital input on all bits used by ADC
-	DIDR0 = _BV(ADC0D) | _BV(ADC1D) | _BV(ADC2D)
+	DIDR0 = _BV(ADC0D) | _BV(ADC1D) | _BV(ADC2D) | _BV(ADC3D)
 		| _BV(ADC4D) | _BV(ADC5D) | _BV(ADC6D);
 
 	// 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
@@ -110,46 +180,77 @@ void susp_adc()
 	DIDR0 = 0;
 }
 
+static void adc1_gain20_adc(uint16_t adcsum)
+{
+	// running average
+	adc1_gain20_offset += adcsum
+			- (adc1_gain20_offset >> ADC1_GAIN20_OFFSET_SHIFT);
+}
+
 ISR(ADC_vect) { // IRQ handler
 	uint16_t adcval = ADCW;
 
-	if (adc_vals)
-		// start the next conversion immediately
-		ADCSRA |= _BV(ADSC);
-
-	if (adc_vals < (1 << sum_shift))
-		 // drop the first conversion, use all others
-		 adc_sum += adcval;
+	if (zero_count) {
+		if (zero_count > 1) {
+			ADCSRA |= _BV(ADSC);
+			zero_count--;
+			return;
+		} else {
+			setup_mux(current_adc);
+			zero_count = 0;
+			/* fall through */
+		}
+	}
 
-	if (adc_vals) {
-		adc_vals--;
+	if (drop_count) {
+		ADCSRA |= _BV(ADSC); // drop this one, start the next
+		drop_count--;
 		return;
 	}
 
-	// Now handle the (1 << sum_shift) measurements
+	if (read_count) {
+		ADCSRA |= _BV(ADSC);
+		adc_sum += adcval;
+		read_count--;
+		return;
+	}
 
-	adcval = adc_sum >> sum_shift;
+	/*
+	 * Now we have performed read_count measurements and have them
+	 * in adc_sum.
+	 */
 
-	if (current_adc == ADC1_GAIN20) {
-		// running average
-		adc1_gain20_offset += adcval
-			- (adc1_gain20_offset >> ADC1_GAIN20_OFFSET_SHIFT);
-	} else if (current_adc == 0 || current_adc == 1) {
+	// For inputs with gain, subtract the measured gain stage offset
+	if (current_adc < 2) {
 		uint16_t offset = adc1_gain20_offset
-			>> (ADC1_GAIN20_OFFSET_SHIFT - sum_shift);
+			>> (ADC1_GAIN20_OFFSET_SHIFT - n_reads_log);
+
 		if (adc_sum > offset)
 			adc_sum -= offset;
 		else
 			adc_sum = 0;
 	}
 
-	if (current_adc < N_PWMLEDS)
+	switch (current_adc) {
+	case 0:
+	case 1:
+	case 2:
 		pwmled_adc(current_adc, adc_sum);
-	if (current_adc == AMBIENT_ADC)
-		ambient_adc(adcval);
-	if (current_adc == BATTERY_ADC)
-		battery_adc(adcval);
-	
+		break;
+	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 ADC1_GAIN20:
+		adc1_gain20_adc(adcval);
+		break;
+	}
+
 	start_next_adc();
 }