From 3f38edc49796a8dd1d03c2dc302be42db2d97d50 Mon Sep 17 00:00:00 2001
From: "Jan \"Yenya\" Kasprzak" <kas@fi.muni.cz>
Date: Mon, 20 May 2013 23:47:05 +0200
Subject: [PATCH] ambient: log minima and maxima

In order to be able to tune the ambient light sensor better, I made
it to log the minimum and maximum values read for every three minutes
or so. When the log buffer fills, start over only after the next
off/on cycle.
---
 firmware/ambient.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++
 firmware/lights.h  |  2 ++
 firmware/main.c    |  1 +
 firmware/tmr.c     |  3 +++
 4 files changed, 53 insertions(+)

diff --git a/firmware/ambient.c b/firmware/ambient.c
index 72e1332..548ff69 100644
--- a/firmware/ambient.c
+++ b/firmware/ambient.c
@@ -1,10 +1,18 @@
 #include <avr/io.h>
+#include <avr/eeprom.h>
 
 #include "lights.h"
 
 #define AMBIENT_VAL_SHIFT 2
 static uint16_t ambient_val;
 volatile unsigned char ambient_zone;
+static unsigned char ambient_min, ambient_max;
+
+/* logging */
+#define AMBIENT_LOG_SIZE 128
+static unsigned char ambient_log_offset_stored EEMEM;
+static unsigned char ambient_log_offset;
+static unsigned char ambient_log[AMBIENT_LOG_SIZE] EEMEM;
 
 /* My photodiode reads 0x00C5 .. 0x033B */
 typedef struct {
@@ -26,7 +34,38 @@ static ambient_zone_t ambient_zones[] = {
 void init_ambient()
 {
 	ambient_val = 0;
+	ambient_max = 0;
+	ambient_min = 0xFF;
 	ambient_zone = 1;
+
+	ambient_log_offset = eeprom_read_byte(&ambient_log_offset_stored);
+
+	if (ambient_log_offset == AMBIENT_LOG_SIZE)
+		ambient_log_offset = 0; // start over
+}
+
+void susp_ambient()
+{
+	unsigned char stored_offset;
+
+	ambient_log_min_max();
+
+	stored_offset = eeprom_read_byte(&ambient_log_offset_stored);
+	if (stored_offset != ambient_log_offset)
+		eeprom_write_byte(&ambient_log_offset_stored,
+			ambient_log_offset);
+}
+
+void ambient_log_min_max()
+{
+	if (ambient_log_offset >= AMBIENT_LOG_SIZE - 1)
+		return;
+
+	eeprom_write_byte(&ambient_log[ambient_log_offset++], ambient_min);
+	eeprom_write_byte(&ambient_log[ambient_log_offset++], ambient_max);
+
+	ambient_min = 0xFF;
+	ambient_max = 0;
 }
 
 void ambient_zone_changed()
@@ -46,6 +85,7 @@ void ambient_zone_changed()
 void ambient_adc(uint16_t adcval)
 {
 	unsigned char old_zone = ambient_zone;
+	unsigned char byte_val;
 
 	ambient_val += adcval - (ambient_val
 		>> (AMBIENT_VAL_SHIFT - AMBIENT_ADC_SHIFT));
@@ -56,6 +96,13 @@ void ambient_adc(uint16_t adcval)
 	while (ambient_zones[ambient_zone].hi < ambient_val)
 		ambient_zone++;
 
+	byte_val = adcval >> 2;
+
+	if (ambient_min > byte_val)
+		ambient_min = byte_val;
+
+	if (ambient_max < byte_val)
+		ambient_max = byte_val;
 #if 0
 	if (old_zone != ambient_zone) {
 		log_byte(0xab);
diff --git a/firmware/lights.h b/firmware/lights.h
index 772613a..6851509 100644
--- a/firmware/lights.h
+++ b/firmware/lights.h
@@ -61,6 +61,8 @@ void gpio_set(unsigned char n, unsigned char on);
 /* ambient.c */
 #define AMBIENT_ADC_SHIFT 0	/* 1 measurement per callback */
 void init_ambient();
+void susp_ambient();
+void ambient_log_min_max();
 extern volatile unsigned char ambient_zone;
 void ambient_adc(uint16_t adc_val);
 
diff --git a/firmware/main.c b/firmware/main.c
index 90bea63..393f47d 100644
--- a/firmware/main.c
+++ b/firmware/main.c
@@ -32,6 +32,7 @@ static void hw_suspend()
 	susp_adc();
 	susp_tmr();
 	susp_gpio();
+	susp_ambient();
 	susp_buttons();
 
 	wdt_disable();
diff --git a/firmware/tmr.c b/firmware/tmr.c
index 23b70b6..d53981a 100644
--- a/firmware/tmr.c
+++ b/firmware/tmr.c
@@ -37,5 +37,8 @@ ISR(TIMER0_COMPA_vect)
 		timer_start_slow_adcs();
 		pattern_div = PATTERN_DIV;
 	}
+
+	if ((jiffies & 0x7FFF) == 0)
+		ambient_log_min_max();
 }
 
-- 
2.39.3