From 541892c2955660bdd068dc7bc0a2611592f408d7 Mon Sep 17 00:00:00 2001
From: "Jan \"Yenya\" Kasprzak" <kas@fi.muni.cz>
Date: Thu, 28 Mar 2013 22:13:58 +0100
Subject: [PATCH] ambient light sensor: configurable # of readings

Set the # of readings to 1, and decrease the shift value
for running average in order to get faster reaction.
---
 firmware/adc.c     |  2 +-
 firmware/ambient.c | 12 +++++++-----
 firmware/lights.h  |  1 +
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/firmware/adc.c b/firmware/adc.c
index f55a427..70c2aa1 100644
--- a/firmware/adc.c
+++ b/firmware/adc.c
@@ -19,7 +19,7 @@ struct {
 	{ 0, 1, PWMLED_ADC_SHIFT },	// pwmled 1
 	{ 0, 1, PWMLED_ADC_SHIFT },	// pwmled 2
 	{ 0, 1, PWMLED_ADC_SHIFT },	// pwmled 3
-	{ 0, 1, 3 },			// ambient
+	{ 0, 1, AMBIENT_ADC_SHIFT },	// ambient
 	{ 0, 1, 0 },			// battery
 	{ 0, 1, 0 },			// gain20
 	{ 0, 1, 0 },			// buttons
diff --git a/firmware/ambient.c b/firmware/ambient.c
index 143ffc4..f626208 100644
--- a/firmware/ambient.c
+++ b/firmware/ambient.c
@@ -2,6 +2,7 @@
 
 #include "lights.h"
 
+#define AMBIENT_VAL_SHIFT 3
 static uint16_t ambient_val;
 volatile unsigned char ambient_zone;
 
@@ -15,10 +16,10 @@ typedef struct {
  * and having small overlaps in order to provide a bit of hysteresis.
  */
 static ambient_zone_t ambient_zones[] = {
-	{ 0x0000, 0xa400 }, // dark
-	{ 0xa000, 0xc000 },
-	{ 0xbe00, 0xc800 },
-	{ 0xc600, 0xffff }
+	{ 0x0000                   , 0x0290<<AMBIENT_VAL_SHIFT }, // dark
+	{ 0x0280<<AMBIENT_VAL_SHIFT, 0x0300<<AMBIENT_VAL_SHIFT }, // evening
+	{ 0x02f8<<AMBIENT_VAL_SHIFT, 0x0320<<AMBIENT_VAL_SHIFT }, // dawn
+	{ 0x0318<<AMBIENT_VAL_SHIFT, 0xffff                    }, // day
 };
 #define N_AMBIENT_ZONES (sizeof(ambient_zones)/sizeof(ambient_zones[0]))
 
@@ -46,7 +47,8 @@ void ambient_adc(uint16_t adcval)
 {
 	unsigned char old_zone = ambient_zone;
 
-	ambient_val += adcval - (ambient_val >> 3);
+	ambient_val += adcval - (ambient_val
+		>> (AMBIENT_VAL_SHIFT - AMBIENT_ADC_SHIFT));
 
 	while (ambient_zones[ambient_zone].lo > ambient_val)
 		ambient_zone--;
diff --git a/firmware/lights.h b/firmware/lights.h
index 2eb1f09..e9d48aa 100644
--- a/firmware/lights.h
+++ b/firmware/lights.h
@@ -59,6 +59,7 @@ void susp_gpio();
 void gpio_set(unsigned char n, unsigned char on);
 
 /* ambient.c */
+#define AMBIENT_ADC_SHIFT 0	/* 1 measurement per callback */
 void init_ambient();
 extern volatile unsigned char ambient_zone;
 void ambient_adc(uint16_t adc_val);
-- 
2.39.3