From 10e546eebdc26c4e725a353d94a51c695131e789 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <tridge@samba.org>
Date: Sat, 17 Dec 2011 07:18:29 +1100
Subject: [PATCH] AnalogSource: return a float from read() method

this gives the full resolution when using the ADC backend. It also
adds scaling for the Arduino backend
---
 libraries/AP_AnalogSource/AP_AnalogSource_ADC.cpp     | 6 +++---
 libraries/AP_AnalogSource/AP_AnalogSource_ADC.h       | 2 +-
 libraries/AP_AnalogSource/AP_AnalogSource_Arduino.cpp | 7 +++++--
 libraries/AP_AnalogSource/AP_AnalogSource_Arduino.h   | 7 +++++--
 libraries/AP_AnalogSource/AnalogSource.h              | 2 +-
 5 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/libraries/AP_AnalogSource/AP_AnalogSource_ADC.cpp b/libraries/AP_AnalogSource/AP_AnalogSource_ADC.cpp
index a400c07ce4..d798d92deb 100644
--- a/libraries/AP_AnalogSource/AP_AnalogSource_ADC.cpp
+++ b/libraries/AP_AnalogSource/AP_AnalogSource_ADC.cpp
@@ -1,9 +1,9 @@
 
 #include "AP_AnalogSource_ADC.h"
 
-int AP_AnalogSource_ADC::read(void)
+float AP_AnalogSource_ADC::read(void)
 {
-    int fullscale = _adc->Ch(_ch);
-    int scaled = _prescale * fullscale;
+    float fullscale = _adc->Ch(_ch);
+    float scaled = _prescale * fullscale;
     return scaled;
 }
diff --git a/libraries/AP_AnalogSource/AP_AnalogSource_ADC.h b/libraries/AP_AnalogSource/AP_AnalogSource_ADC.h
index c6807eaba1..dd8d73dc2c 100644
--- a/libraries/AP_AnalogSource/AP_AnalogSource_ADC.h
+++ b/libraries/AP_AnalogSource/AP_AnalogSource_ADC.h
@@ -10,7 +10,7 @@ class AP_AnalogSource_ADC : public AP_AnalogSource
     public:
     AP_AnalogSource_ADC( AP_ADC * adc, int ch, float prescale = 1.0 ) :
         _adc(adc), _ch(ch), _prescale(prescale) {}
-    int read(void);
+    float read(void);
 
     private:
     AP_ADC * _adc;
diff --git a/libraries/AP_AnalogSource/AP_AnalogSource_Arduino.cpp b/libraries/AP_AnalogSource/AP_AnalogSource_Arduino.cpp
index d8f389dcf0..3406a59a22 100644
--- a/libraries/AP_AnalogSource/AP_AnalogSource_Arduino.cpp
+++ b/libraries/AP_AnalogSource/AP_AnalogSource_Arduino.cpp
@@ -1,8 +1,11 @@
+/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
 
 #include "wiring.h"
 #include "AP_AnalogSource_Arduino.h"
 
-int AP_AnalogSource_Arduino::read(void)
+float AP_AnalogSource_Arduino::read(void)
 {
-    return analogRead(_pin);
+	float fullscale = analogRead(_pin);
+	float scaled = _prescale * fullscale;
+	return scaled;
 }
diff --git a/libraries/AP_AnalogSource/AP_AnalogSource_Arduino.h b/libraries/AP_AnalogSource/AP_AnalogSource_Arduino.h
index ba17f50fd6..31eb895501 100644
--- a/libraries/AP_AnalogSource/AP_AnalogSource_Arduino.h
+++ b/libraries/AP_AnalogSource/AP_AnalogSource_Arduino.h
@@ -1,3 +1,4 @@
+/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
 
 #ifndef __AP_ANALOG_SOURCE_ARDUINO_H__
 #define __AP_ANALOG_SOURCE_ARDUINO_H__
@@ -7,11 +8,13 @@
 class AP_AnalogSource_Arduino : public AP_AnalogSource
 {
     public:
-    AP_AnalogSource_Arduino( int pin ) : _pin(pin) {}
-    int read(void);
+    AP_AnalogSource_Arduino( int pin, float prescale = 1.0 ) : 
+        _pin(pin), _prescale(prescale) {}
+    float read(void);
 
     private:
     int _pin;
+    float _prescale;
 };
 
 #endif // __AP_ANALOG_SOURCE_ARDUINO_H__
diff --git a/libraries/AP_AnalogSource/AnalogSource.h b/libraries/AP_AnalogSource/AnalogSource.h
index 1a5ad7e6f3..cbd2b6c96d 100644
--- a/libraries/AP_AnalogSource/AnalogSource.h
+++ b/libraries/AP_AnalogSource/AnalogSource.h
@@ -5,7 +5,7 @@
 class AP_AnalogSource
 {
     public:
-    virtual int read(void) = 0;
+    virtual float read(void) = 0;
 };
 
 #endif // __ANALOG_SOURCE_H__