adc: battery adc

[bike-lights.git] / adc.c

diff --git a/adc.c b/adc.c
index a37e95886f237828537666d5bb209048a521eaeb..bef7375e8b54f40167e4c591a10021a0b653360e 100644 (file)
--- a/adc.c
+++ b/adc.c
@@ -3,6 +3,7 @@
 
 #include "lights.h"
 
+/* ADC numbering: PWM LEDs first, then ambient light sensor, battery sensor */
 static unsigned char adc_mux[] = { // pwmleds should be first
        // 0: pwmled 0: 1.1V, ADC3 (PA4), single-ended
        _BV(REFS1) | _BV(MUX1) | _BV(MUX0),
@@ -16,8 +17,12 @@ static unsigned char adc_mux[] = { // pwmleds should be first
        _BV(REFS1) | _BV(MUX2) | _BV(MUX0),
 };
 
-#define LAST_ADC (sizeof(adc_mux)/sizeof(char))
-volatile static unsigned char current_adc = LAST_ADC;
+#define AMBIENT_ADC N_PWMLEDS
+#define BATTERY_ADC (N_PWMLEDS + 1)
+
+#define LAST_ADC (sizeof(adc_mux)/sizeof(adc_mux[0]))
+volatile static unsigned char current_adc;
+static unsigned char adc_ignore;
 
 static void start_next_adc()
 {
@@ -25,9 +30,11 @@ static void start_next_adc()
                --current_adc;
 
                // test if current_adc should be measured
-               if (current_adc < N_PWMLEDS && pwmled_is_on(current_adc))
+               if (current_adc < N_PWMLEDS && pwmled_needs_adc(current_adc))
+                       goto found;
+               if (current_adc == AMBIENT_ADC)
                        goto found;
-               // TODO ambient light, battery sense, etc.
+               // TODO battery sense, etc.
        }
 
        // all ADCs have been handled
@@ -36,11 +43,15 @@ static void start_next_adc()
 found:
        // ADCSRB |= _BV(GSEL); // gain 8 or 32
        ADMUX = adc_mux[current_adc]; // set up mux, start one-shot conversion
+       adc_ignore = 1; // ignore first reading after mux change
        ADCSRA |= _BV(ADSC);
 }
 
 void init_adc()
 {
+       current_adc = LAST_ADC;
+       adc_ignore = 1;
+
        ADCSRA = _BV(ADEN)                      // enable
                | _BV(ADPS1) | _BV(ADPS0)       // CLK/8 = 125 kHz
                // | _BV(ADPS2)                 // CLK/16 = 62.5 kHz
@@ -64,9 +75,23 @@ void init_adc()
 ISR(ADC_vect) { // IRQ handler
        uint16_t adcval = ADCW;
 
+#if 0
+       log_byte(0xF3);
+       log_byte(current_adc);
+       log_word(adcval);
+#endif
+
+       if (adc_ignore) {
+               ADCSRA |= _BV(ADSC);
+               adc_ignore = 0;
+               return;
+       }
+
        if (current_adc < N_PWMLEDS)
                pwmled_adc(current_adc, adcval);
-       // TODO ambient light, battery sense, etc.
+       if (current_adc == AMBIENT_ADC)
+               ambient_adc(adcval);
+       // TODO battery sense, etc.
        
        start_next_adc();
 }