adc.c: for one pwmled only

projects/step-up/adc.c

@@ -4,32 +4,13 @@
 
 #include "lights.h"
 
-#define BATTERY_ADC (N_PWMLEDS + 0)
-#define BUTTON_ADC  (N_PWMLEDS + 1)
-#define ZERO_ADC    (N_PWMLEDS + 2)
+#define ZERO_ADC    1
 
 //#define NUM_ADCS	ZERO_ADC
 #define NUM_ADCS	1
 
-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
-#if 0
-	{ 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
-#endif
-};
-
 volatile static unsigned char current_adc, current_slow_adc;
-static uint16_t adc_sum, zero_count, drop_count, read_count, n_reads_log;
-
+static uint16_t adc_sum, read_zero, drop_count, read_count, n_reads_log;
 
 static void setup_mux(unsigned char n)
 {
@@ -72,23 +53,14 @@ void start_next_adc()
 #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
-		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_zero = 0;
+	drop_count = 1;
 
-	read_count = 1 << adc_params[current_adc].read_keep_log;
-	n_reads_log = adc_params[current_adc].read_keep_log;
+	read_count = 1 << PWMLED_ADC_SHIFT;
+	n_reads_log = PWMLED_ADC_SHIFT;
 
 	// set up mux, start one-shot conversion
-	if (zero_count > 1)
+	if (read_zero)
 		setup_mux(ZERO_ADC);
 	else
 		setup_mux(current_adc);
@@ -96,6 +68,7 @@ void start_next_adc()
 	ADCSRA |= _BV(ADSC);
 }
 
+#if 0
 void timer_start_slow_adcs()
 {
 	if (current_slow_adc > N_PWMLEDS) { // Don't start if in progress
@@ -105,6 +78,7 @@ void timer_start_slow_adcs()
 		// TODO: kick the watchdog here
 	}
 }
+#endif
 
 /*
  * Single synchronous ADC conversion.
@@ -128,7 +102,6 @@ static uint16_t read_adc_sync()
 
 void init_adc()
 {
-	unsigned char i;
 	current_slow_adc = NUM_ADCS;
 	current_adc = 0;
 
@@ -170,16 +143,11 @@ static void adc1_gain20_adc(uint16_t adcsum)
 ISR(ADC_vect) { // IRQ handler
 	uint16_t adcval = ADCW;
 
-	if (zero_count) {
-		if (zero_count > 1) {
-			ADCSRA |= _BV(ADSC);
-			zero_count--;
-			return;
-		} else {
-			setup_mux(current_adc);
-			zero_count = 0;
-			/* fall through */
-		}
+	if (read_zero) {
+		setup_mux(current_adc);
+		read_zero = 0;
+		ADCSRA |= _BV(ADSC); // drop this one, start the next
+		return;
 	}
 
 	if (drop_count) {
@@ -189,7 +157,7 @@ ISR(ADC_vect) { // IRQ handler
 	}
 
 	if (read_count) {
-		ADCSRA |= _BV(ADSC);
+		ADCSRA |= _BV(ADSC); // immediately start the next conversion
 		adc_sum += adcval;
 		read_count--;
 		return;