From 38c8a83779ea2903a6067864fcef003245f451e0 Mon Sep 17 00:00:00 2001
From: Heikki Hannikainen <hessuh@rockbox.org>
Date: Wed, 7 Aug 2002 11:30:39 +0000
Subject: Made battery_level() use the power history table to get an average
 battery level over the last 3 minutes.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@1589 a1c6a512-1295-4272-9138-f99709370657
---
 firmware/powermgmt.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 firmware/powermgmt.h | 16 ++++++++++++++-
 2 files changed, 70 insertions(+), 3 deletions(-)

diff --git a/firmware/powermgmt.c b/firmware/powermgmt.c
index 602819f443..3f919fa177 100644
--- a/firmware/powermgmt.c
+++ b/firmware/powermgmt.c
@@ -29,7 +29,19 @@
 #include "power.h"
 #include "powermgmt.h"
 
-#ifndef SIMULATOR
+#ifdef SIMULATOR
+
+int battery_level(void)
+{
+    return 100;
+}
+
+bool battery_level_safe(void)
+{
+    return true;
+}
+
+#else /* not SIMULATOR */
 
 static char power_stack[DEFAULT_STACK_SIZE];
 static char power_thread_name[] = "power";
@@ -40,6 +52,46 @@ char power_message[POWER_MESSAGE_LEN] = "";
 char charge_restart_level = CHARGE_RESTART_HI;
 #endif
 
+/* Returns battery level in percent */
+int battery_level(void)
+{
+    int level = 0;
+    int c = 0;
+    int i;
+    
+    /* calculate average over last 3 minutes (skip empty samples) */
+    for (i = 0; i < 3; i++)
+        if (power_history[POWER_HISTORY_LEN-1-i]) {
+            level += power_history[POWER_HISTORY_LEN-1-i];
+            c++;
+        }
+        
+    if (c)
+        level = level / c;  /* avg */
+    else /* history was empty, get a fresh sample */
+        level = (adc_read(ADC_UNREG_POWER) * BATTERY_SCALE_FACTOR) / 10000;
+
+#ifdef HAVE_CHARGE_CTRL    
+    if (charger_enabled)
+    	level -= 10;  /* the charger raises the voltage 0.05-0.2v */
+#endif
+    
+    if(level > BATTERY_LEVEL_FULL)
+        level = BATTERY_LEVEL_FULL;
+
+    if(level < BATTERY_LEVEL_EMPTY)
+        level = BATTERY_LEVEL_EMPTY;
+
+    return ((level-BATTERY_LEVEL_EMPTY) * 100) / BATTERY_RANGE;
+}
+
+/* Tells if the battery level is safe for disk writes */
+bool battery_level_safe(void)
+{
+    /* I'm pretty sure we don't want an average over a long time here */
+    return adc_read(ADC_UNREG_POWER) > (BATTERY_LEVEL_DANGEROUS * 10000) / BATTERY_SCALE_FACTOR;
+}
+
 /*
  * This power thread maintains a history of battery voltage
  * and should, in the future, enable charging when it's needed
@@ -175,4 +227,5 @@ void power_init(void)
     create_thread(power_thread, power_stack, sizeof(power_stack), power_thread_name);
 }
 
-#endif
+#endif /* SIMULATOR */
+
diff --git a/firmware/powermgmt.h b/firmware/powermgmt.h
index 751409b803..bfee5bf4a3 100644
--- a/firmware/powermgmt.h
+++ b/firmware/powermgmt.h
@@ -21,6 +21,13 @@
 
 #ifndef SIMULATOR
 
+#define BATTERY_LEVEL_SHUTDOWN   450 /* 4.5V */
+#define BATTERY_LEVEL_EMPTY      465 /* 4.65V */
+#define BATTERY_LEVEL_DANGEROUS  475 /* 4.75V */
+#define BATTERY_LEVEL_FULL       520 /* 5.2V */
+
+#define BATTERY_RANGE (BATTERY_LEVEL_FULL - BATTERY_LEVEL_EMPTY)
+
 #define POWER_HISTORY_LEN 2*60   /* 2 hours of samples, one per minute */
 #define POWER_AVG         3      /* how many samples to take for each measurement */
 
@@ -42,8 +49,15 @@ extern char charge_restart_level;
 
 extern unsigned short power_history[POWER_HISTORY_LEN];
 
+/* Start up power management thread */
 void power_init(void);
 
-#endif
+#endif /* SIMULATOR */
+
+/* Returns battery level in percent */
+int battery_level(void);
+
+/* Tells if the battery level is safe for disk writes */
+bool battery_level_safe(void);
 
 #endif
-- 
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