joystick.cpp

#include "joystick.h"
#include "mbed.h"

Joystick::Joystick(PinName x_axis_pin, PinName y_axis_pin, PinName button_pin)
{
    x_axis_ = new AnalogIn(x_axis_pin);
    y_axis_ = new AnalogIn(y_axis_pin);
    button_ = new InterruptIn(button_pin);
    button_debounce_ = new Timeout();
}

Joystick::~Joystick() 
{
    delete x_axis_;
    delete y_axis_;
    delete button_;
    delete button_debounce_;
}

void Joystick::init() //function responsible for initializing Joystick
{                       // and raising interrupts  
        //Sets up the button ISR
    button_->mode(PullDown);
    button_->rise(this, &Joystick::button_isr);
    button_->fall(this, &Joystick::button_fall_isr);

        //Initalises the vairables and flags
    x_offset_ = 0;
    y_offset_ = 0;
    g_button_flag_ = false;
    g_button_debounce_flag_ = false;

        //Samples the joystick 5 times and takes an average to get the offset
    float x_sum = 0;
    float y_sum = 0;

    for (int i = 0; i < 5; ++i) {
        x_sum += x_axis_->read();
        y_sum += y_axis_->read();
    }

    x_offset_ = 0.5f - x_sum/5.0f;
    y_offset_ = 0.5f - y_sum/5.0f;
}

float Joystick::GetXValue() 
{

    float x_sum = 0;
        //Iterates 5 times and then will calculate an average
    for (int i = 0; i < 5; ++i) {
        x_sum += x_axis_->read();
    }

    float x_value = x_sum/5.0f + x_offset_;

        //Caps the value for the POT between 0 and 1
    if (x_value < 0.0f) {
        return 0;
    } else if (x_value > 1.0f) {
        return 1;
    } else {
        return x_value;
    }
}

float Joystick::GetYValue() 
{

    float y_sum = 0;
        //Iterates 5 times and calculates an average
    for (int i = 0; i < 5; ++i) {
        y_sum += y_axis_->read();
    }

    float y_value = y_sum/5.0f + y_offset_;

        //Caps the value for the POT between 0 and 1
    if (y_value < 0.0f) {
        return 0;
    } else if (y_value > 1.0f) {
        return 1;
    } else {
        return y_value;
    }
}

int Joystick::get_button_flag() 
{
    return g_button_flag_;
}

void Joystick::set_button_flag(bool value) 
{
    g_button_flag_ = value;
}

void Joystick::button_isr() //raises interrupt on button press
{
    if (!g_button_debounce_flag_) {
        g_button_flag_ = true;
        g_button_debounce_flag_ = true;
    }
}

void Joystick::button_fall_isr() 
{
    button_debounce_->attach(this, &Joystick::button_debounce_isr, 0.125);
}

void Joystick::button_debounce_isr() 
{
    g_button_debounce_flag_ = false;
}