Joystick.cpp

00001 /**
00002 @file Joystick.cpp
00003 
00004 @brief Member functions implementations
00005 
00006 */
00007 #include "Joystick.h"
00008 #include "mbed.h"
00009 
00010 Joystick::Joystick(PinName x_axis_pin, PinName y_axis_pin, PinName button_pin) 
00011 {
00012     x_axis_ = new AnalogIn(x_axis_pin);
00013     y_axis_ = new AnalogIn(y_axis_pin);
00014     button_ = new InterruptIn(button_pin);
00015     button_debounce_ = new Timeout();
00016 }
00017 
00018 Joystick::~Joystick() 
00019 {
00020     delete x_axis_;
00021     delete y_axis_;
00022     delete button_;
00023     delete button_debounce_;
00024 }
00025 
00026 void Joystick::init() 
00027 {
00028         //Sets up the button ISR
00029     button_->mode(PullDown);
00030     button_->rise(this, &Joystick::button_isr);
00031     button_->fall(this, &Joystick::button_fall_isr);
00032 
00033         //Initalises the vairables and flags
00034     x_offset_ = 0;
00035     y_offset_ = 0;
00036     g_button_flag_ = false;
00037     g_button_debounce_flag_ = false;
00038 
00039         //Samples the joystick 5 times and takes an average to get the offset
00040     float x_sum = 0;
00041     float y_sum = 0;
00042 
00043     for (int i = 0; i < 5; ++i) {
00044         x_sum += x_axis_->read();
00045         y_sum += y_axis_->read();
00046     }
00047 
00048     x_offset_ = 0.5f - x_sum/5.0f;
00049     y_offset_ = 0.5f - y_sum/5.0f;
00050 }
00051 
00052 float Joystick::GetXValue() 
00053 {
00054 
00055     float x_sum = 0;
00056         //Iterates 5 times and calculates an average
00057     for (int i = 0; i < 5; ++i) {
00058         x_sum += x_axis_->read();
00059     }
00060 
00061     float x_value = x_sum/5.0f + x_offset_;
00062 
00063         //Caps the value for the POT between 0 and 1
00064     if (x_value < 0.0f) {
00065         return 0;
00066     } else if (x_value > 1.0f) {
00067         return 1;
00068     } else {
00069         return x_value;
00070     }
00071 }
00072 
00073 float Joystick::GetYValue() 
00074 {
00075 
00076     float y_sum = 0;
00077         //Iterates 5 times and calculates an average
00078     for (int i = 0; i < 5; ++i) {
00079         y_sum += y_axis_->read();
00080     }
00081 
00082     float y_value = y_sum/5.0f + y_offset_;
00083 
00084         //Caps the value for the POT between 0 and 1
00085     if (y_value < 0.0f) {
00086         return 0;
00087     } else if (y_value > 1.0f) {
00088         return 1;
00089     } else {
00090         return y_value;
00091     }
00092 }
00093 
00094 int Joystick::get_button_flag() 
00095 {
00096     return g_button_flag_;
00097 }
00098 
00099 void Joystick::set_button_flag(bool value) 
00100 {
00101     g_button_flag_ = value;
00102 }
00103 
00104 void Joystick::button_isr() 
00105 {
00106     if (!g_button_debounce_flag_) {
00107         g_button_flag_ = true;
00108         g_button_debounce_flag_ = true;
00109     }
00110 }
00111 
00112 void Joystick::button_fall_isr() 
00113 {
00114     button_debounce_->attach(this, &Joystick::button_debounce_isr, 0.125);
00115 }
00116 
00117 void Joystick::button_debounce_isr() 
00118 {
00119     g_button_debounce_flag_ = false;
00120 }