From e5360facc2b16d902a9c891e9cd8aadcc3c21e39 Mon Sep 17 00:00:00 2001
From: "Jan \"Yenya\" Kasprzak" <kas@fi.muni.cz>
Date: Tue, 28 Aug 2012 16:54:03 +0200
Subject: [PATCH] ambient light sensor

---
 Makefile  |  2 +-
 adc.c     | 10 ++++++++--
 ambient.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 lights.h  |  5 +++++
 main.c    |  1 +
 5 files changed, 66 insertions(+), 3 deletions(-)
 create mode 100644 ambient.c

diff --git a/Makefile b/Makefile
index c2e1d6a..e7b6355 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 
 PROGRAM=lights
-SRC=main.c logging.c adc.c pwm.c tmr.c pwmled.c gpio.c
+SRC=main.c logging.c adc.c pwm.c tmr.c pwmled.c gpio.c ambient.c
 OBJ=$(SRC:.c=.o)
 
 
diff --git a/adc.c b/adc.c
index a37e958..b758721 100644
--- a/adc.c
+++ b/adc.c
@@ -16,6 +16,8 @@ static unsigned char adc_mux[] = { // pwmleds should be first
 	_BV(REFS1) | _BV(MUX2) | _BV(MUX0),
 };
 
+#define AMBIENT_ADC N_PWMLEDS
+
 #define LAST_ADC (sizeof(adc_mux)/sizeof(char))
 volatile static unsigned char current_adc = LAST_ADC;
 
@@ -27,7 +29,9 @@ static void start_next_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.
+		if (current_adc == AMBIENT_ADC)
+			goto found;
+		// TODO battery sense, etc.
 	}
 
 	// all ADCs have been handled
@@ -66,7 +70,9 @@ ISR(ADC_vect) { // IRQ handler
 
 	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();
 }
diff --git a/ambient.c b/ambient.c
new file mode 100644
index 0000000..e91c1ae
--- /dev/null
+++ b/ambient.c
@@ -0,0 +1,51 @@
+#include <avr/io.h>
+
+#include "lights.h"
+
+static uint16_t ambient_val;
+unsigned char ambient_zone;
+unsigned char ambient_zone_set;
+
+static uint16_t ambient_zones[] = {
+	1, 2, 10, 20, 256
+};
+#define N_AMBIENT_ZONES (sizeof(ambient_zones)/sizeof(ambient_zones[0]))
+
+void ambient_init()
+{
+	ambient_val = 0;
+	ambient_zone = 0;
+	ambient_zone_set = 0;
+}
+
+void ambient_zone_changed()
+{
+	log_byte(0xCC);
+	log_byte(ambient_zone);
+	log_word(ambient_val);
+}
+
+void ambient_adc(uint16_t adcval)
+{
+	unsigned char newzone;
+
+	if (!ambient_zone_set)
+		ambient_val = adcval << 4;
+
+	// running sum
+	ambient_val += adcval - (ambient_val >> 4);
+
+	newzone = 0;
+	while (newzone < N_AMBIENT_ZONES-1
+		&& ambient_zones[newzone] <= ambient_val)
+		newzone++;
+
+	if (!ambient_zone_set || newzone != ambient_zone) {
+		ambient_zone = newzone;
+		ambient_zone_changed();
+		ambient_zone_set = 1;
+	}
+}
+
+
+
diff --git a/lights.h b/lights.h
index 6619be7..74e887d 100644
--- a/lights.h
+++ b/lights.h
@@ -47,5 +47,10 @@ unsigned char pwmled_is_on(unsigned char n);
 void gpio_init();
 void gpio_set(unsigned char n, unsigned char on);
 
+/* ambient.c */
+void ambient_init();
+extern unsigned char ambient_zone;
+void ambient_adc(uint16_t adc_val);
+
 #endif /* !LIGHTS_H__ */
 
diff --git a/main.c b/main.c
index fe906e5..7b63ad8 100644
--- a/main.c
+++ b/main.c
@@ -16,6 +16,7 @@ int main(void)
 
 	pwmled_init();
 	gpio_init();
+	ambient_init();
 
 	log_set_state(3);
 
-- 
2.43.5