From d9b7a2c6bd523fe1a93e075ca7d5ddc379af8fe8 Mon Sep 17 00:00:00 2001
From: schneider <schneider@blinkenlichts.net>
Date: Thu, 19 Jan 2012 23:01:00 +0100
Subject: [PATCH] added some filtering for the voltage reading

---
 firmware/basic/voltage.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/firmware/basic/voltage.c b/firmware/basic/voltage.c
index 4996077..ff37ab6 100644
--- a/firmware/basic/voltage.c
+++ b/firmware/basic/voltage.c
@@ -3,26 +3,31 @@
 #include "basic/basic.h"
 #include "funk/nrf24l01p.h"
 
-static uint32_t voltage=5000;
+#define VOLTAGE_SAMPLES     8
+static uint32_t voltage=5000*VOLTAGE_SAMPLES;
 static uint8_t chrg=1;
 
 void VoltageCheck(void){
-
+    uint32_t v;
     chrg=gpioGetValue(RB_PWR_CHRG);
-    //slow down the adc for our high impedance volatage devider
+    //slow down the adc for our high impedance voltage devider
     ADC_AD0CR = ((CFG_CPU_CCLK / SCB_SYSAHBCLKDIV) / 100000 - 1 ) << 8;
-	voltage = adcRead(1);
+	v = adcRead(1);
     //speed it up again
     ADC_AD0CR = ((CFG_CPU_CCLK / SCB_SYSAHBCLKDIV) / 1000000 - 1 ) << 8;
 
-	voltage *= 10560;
-	voltage /= 1024;
+	v *= 10560;
+	v /= 1024;
     
     //add the drop over the voltage switch
-    voltage += 50;
+    v += 50;
+    
+    voltage -= voltage/VOLTAGE_SAMPLES;
+    voltage += v;
 
     //battery is assumed empty if the volatge falls bellow 3.5V
-	if( voltage < 3500 ){
+	if( voltage < (3500*VOLTAGE_SAMPLES) ){
+	//if( voltage < 3500 ){
         nrf_off();
 	    gpioSetValue (RB_PWR_GOOD, 0); 
 	    gpioSetValue (RB_LCD_BL, 0);
@@ -35,7 +40,8 @@ void VoltageCheck(void){
 };
 
 uint32_t GetVoltage(void){
-    return voltage;
+    return voltage/8;
+    //return voltage;
 };
 
 uint8_t GetChrgStat(void){