X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?a=blobdiff_plain;f=adc.c;fp=adc.c;h=a37e95886f237828537666d5bb209048a521eaeb;hb=4b93ea55987c25fcce022403a505ca1749dc329c;hp=0000000000000000000000000000000000000000;hpb=1647725c8e3e1297a330e5ab18ad6033fec807dd;p=bike-lights.git

diff --git a/adc.c b/adc.c
new file mode 100644
index 0000000..a37e958
--- /dev/null
+++ b/adc.c
@@ -0,0 +1,79 @@
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+#include "lights.h"
+
+static unsigned char adc_mux[] = { // pwmleds should be first
+	// 0: pwmled 0: 1.1V, ADC3 (PA4), single-ended
+	_BV(REFS1) | _BV(MUX1) | _BV(MUX0),
+	// 1: pwmled 1: 1.1V, ADC0,1 (PA0,1), gain 1 or 8
+	_BV(REFS1) | _BV(MUX3) | _BV(MUX2),
+	// 2: pwmled 2: 1.1V, ADC2,1 (PA2,1), gain 1 or 8
+	_BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1) | _BV(MUX0),
+	// 3: ambient light: 1.1V, ADC4 (PA5), single-ended
+	_BV(REFS1) | _BV(MUX2),
+	// 4: batt voltage: 1.1V, ADC5 (PA6), single-ended
+	_BV(REFS1) | _BV(MUX2) | _BV(MUX0),
+};
+
+#define LAST_ADC (sizeof(adc_mux)/sizeof(char))
+volatile static unsigned char current_adc = LAST_ADC;
+
+static void start_next_adc()
+{
+	while (current_adc > 0) {
+		--current_adc;
+
+		// test if current_adc should be measured
+		if (current_adc < N_PWMLEDS && pwmled_is_on(current_adc))
+			goto found;
+		// TODO ambient light, battery sense, etc.
+	}
+
+	// all ADCs have been handled
+	current_adc = LAST_ADC;
+	return;
+found:
+	// ADCSRB |= _BV(GSEL); // gain 8 or 32
+	ADMUX = adc_mux[current_adc]; // set up mux, start one-shot conversion
+	ADCSRA |= _BV(ADSC);
+}
+
+void init_adc()
+{
+	ADCSRA = _BV(ADEN)			// enable
+		| _BV(ADPS1) | _BV(ADPS0)	// CLK/8 = 125 kHz
+		// | _BV(ADPS2)			// CLK/16 = 62.5 kHz
+		;
+	ADCSRB |= _BV(GSEL); // gain 8 or 32
+
+	// Disable digital input on all bits used by ADC
+	DIDR0 = _BV(ADC0D) | _BV(ADC1D) | _BV(ADC2D) | _BV(ADC3D)
+		| _BV(ADC4D) | _BV(ADC5D);
+
+	ADCSRA |= _BV(ADSC);
+
+	/* Do first conversion and drop the result */
+	while ((ADCSRA & _BV(ADIF)) == 0)
+		;
+	ADCSRA |= _BV(ADIF); // clear the IRQ flag
+
+	ADCSRA |= _BV(ADIE); // enable IRQ
+}
+
+ISR(ADC_vect) { // IRQ handler
+	uint16_t adcval = ADCW;
+
+	if (current_adc < N_PWMLEDS)
+		pwmled_adc(current_adc, adcval);
+	// TODO ambient light, battery sense, etc.
+	
+	start_next_adc();
+}
+
+void timer_start_adcs()
+{
+	if (current_adc == LAST_ADC) // Don't start if in progress
+		start_next_adc();
+}
+