File content as of revision 4:bafb7f483e93:

#include "Gamepad.h"

//////////// constructor/destructor ////////////
Gamepad::Gamepad()
{
    led_1 = new PwmOut(PTA1);
    led_2 = new PwmOut(PTA2);
    led_3 = new PwmOut(PTC2);
    led_4 = new PwmOut(PTC3);
    led_5 = new PwmOut(PTC4);
    led_6 = new PwmOut(PTD3);

    button_A = new InterruptIn(PTB9);
    button_B = new InterruptIn(PTD0);
    button_X = new InterruptIn(PTC17);
    button_Y = new InterruptIn(PTC12);  
    button_back = new InterruptIn(PTB19);
    button_start = new InterruptIn(PTC5);
    button_L = new InterruptIn(PTB18);
    button_R = new InterruptIn(PTB3);
    button_joystick = new InterruptIn(PTC16);
    
    vert = new AnalogIn(PTB10);
    horiz = new AnalogIn(PTB11);

    buzzer = new PwmOut(PTC10);
    pot = new AnalogIn(PTB2);

    timeout = new Timeout();

}

Gamepad::~Gamepad()
{
    delete led_1,led_2,led_3,led_4,led_5,led_6;
    delete button_A,button_B,button_joystick,vert,horiz;
    delete button_X, button_Y, button_back, button_start;
    delete button_L, button_R, buzzer, pot, timeout;
}

///////////////// public methods /////////////////

void Gamepad::init()
{
    leds_off();
    
    // read centred values of joystick
    _x0 = horiz->read();
    _y0 = vert->read();

    buzzer->period(1.0/1000.0);  // 1 kHz

    // clear all flags
    a_flag=0,b_flag=0,x_flag=0,y_flag=0,joy_flag=0;
    l_flag=0,r_flag=0,back_flag=0,start_flag=0;

}

void Gamepad::leds_off()
{
    fade_leds(0.0);
}

void Gamepad::leds_on()
{
    fade_leds(1.0);
}

void Gamepad::fade_leds(float val)
{
    if (val < 0.0f) {
        val = 0.0f;
    }
    if (val > 1.0f) {
        val = 1.0f;
    }

    // leds are active-low, so subtract from 1.0
    // 0.0 corresponds to fully-off, 1.0 to fully-on
    val = 1.0f - val;

    led_1->write(val);
    led_2->write(val);
    led_3->write(val);
    led_4->write(val);
    led_5->write(val);
    led_6->write(val);
}

float Gamepad::read_pot()
{
    return pot->read();
}

void Gamepad::tone(float frequency, float duration)
{
    buzzer->period(1.0f/frequency);
    buzzer->write(0.5);  // 50% duty cycle - square wave
    timeout->attach(callback(this, &Gamepad::tone_off), duration );
}

bool Gamepad::a_pressed()
{
    // ISR must have been triggered
    if (a_flag) {
        a_flag = 0;  // clear flag
        return true;
    } else {
        return false;
    }
}

bool Gamepad::b_pressed()
{
    // ISR must have been triggered
    if (b_flag) {
        b_flag = 0;  // clear flag
        return true;
    } else {
        return false;
    }
}

bool Gamepad::x_pressed()
{
    // ISR must have been triggered
    if (x_flag) {
        x_flag = 0;  // clear flag
        return true;
    } else {
        return false;
    }
}

bool Gamepad::y_pressed()
{
    // ISR must have been triggered
    if (y_flag) {
        y_flag = 0;  // clear flag
        return true;
    } else {
        return false;
    }
}

bool Gamepad::l_pressed()
{
    // ISR must have been triggered
    if (l_flag) {
        l_flag = 0;  // clear flag
        return true;
    } else {
        return false;
    }
}

bool Gamepad::r_pressed()
{
    // ISR must have been triggered
    if (r_flag) {
        r_flag = 0;  // clear flag
        return true;
    } else {
        return false;
    }
}

bool Gamepad::back_pressed()
{
    // ISR must have been triggered
    if (back_flag) {
        back_flag = 0;  // clear flag
        return true;
    } else {
        return false;
    }
}

bool Gamepad::start_pressed()
{
    // ISR must have been triggered
    if (a_flag) {
        a_flag = 0;  // clear flag
        return true;
    } else {
        return false;
    }
}

bool Gamepad::joystick_pressed()
{
    // ISR must have been triggered
    if (joy_flag) {
        joy_flag = 0;  // clear flag
        return true;
    } else {
        return false;
    }
}

// this method gets the magnitude of the joystick movement
float Gamepad::get_mag()
{
    Polar p = get_polar();
    return p.mag;
}

// this method gets the angle of joystick movement (0 to 360, 0 North)
float Gamepad::get_angle()
{
    Polar p = get_polar();
    return p.angle;
}

Direction Gamepad::get_direction()
{
    float angle = get_angle();  // 0 to 360, -1 for centred

    Direction d;
    // partition 360 into segments and check which segment the angle is in
    if (angle < 0.0f) {
        d = CENTRE;   // check for -1.0 angle
    } else if (angle < 22.5f) {  // then keep going in 45 degree increments
        d = N;
    } else if (angle < 67.5f) {
        d = NE;
    } else if (angle < 112.5f) {
        d = E;
    } else if (angle < 157.5f) {
        d = SE;
    } else if (angle < 202.5f) {
        d = S;
    } else if (angle < 247.5f) {
        d = SW;
    } else if (angle < 292.5f) {
        d = W;
    } else if (angle < 337.5f) {
        d = NW;
    } else {
        d = N;
    }

    return d;
}

///////////////////// private methods ////////////////////////

void Gamepad::tone_off()
{
    buzzer->write(0.0);
}

void Gamepad::init_buttons()
{
    // turn on pull-downs as other side of button is connected to 3V3
    // button is 0 when not pressed and 1 when pressed
    button_A->mode(PullDown);
    button_B->mode(PullDown);
    button_X->mode(PullDown);
    button_Y->mode(PullDown);
    button_back->mode(PullDown);
    button_start->mode(PullDown);
    button_L->mode(PullDown);
    button_R->mode(PullDown);
    button_joystick->mode(PullDown);
    // therefore setup rising edge interrupts
    button_A->rise(callback(this,&Gamepad::a_isr));
    button_B->rise(callback(this,&Gamepad::b_isr));
    button_X->rise(callback(this,&Gamepad::x_isr));
    button_Y->rise(callback(this,&Gamepad::y_isr));
    button_L->rise(callback(this,&Gamepad::l_isr));
    button_R->rise(callback(this,&Gamepad::r_isr));
    button_start->rise(callback(this,&Gamepad::start_isr));
    button_back->rise(callback(this,&Gamepad::back_isr));
    button_joystick->rise(callback(this,&Gamepad::joy_isr));
}

// button interrupts ISRs
void Gamepad::a_isr()
{
    a_flag=1;
}
void Gamepad::b_isr()
{
    b_flag=1;
}
void Gamepad::x_isr()
{
    x_flag=1;
}
void Gamepad::y_isr()
{
    y_flag=1;
}
void Gamepad::l_isr()
{
    l_flag=1;
}
void Gamepad::r_isr()
{
    r_flag=1;
}
void Gamepad::back_isr()
{
    back_flag=1;
}
void Gamepad::start_isr()
{
    start_flag=1;
}
void Gamepad::joy_isr()
{
    joy_flag=1;
}

// get raw joystick coordinate in range -1 to 1
// Direction (x,y)
// North     (0,1)
// East      (1,0)
// South     (0,-1)
// West      (-1,0)
Vector2D Gamepad::get_coord()
{
    // read() returns value in range 0.0 to 1.0 so is scaled and centre value
    // substracted to get values in the range -1.0 to 1.0
    float x = 2.0f*( horiz->read() - _x0 );
    float y = 2.0f*( vert->read() - _y0 );

    // Note: the x value here is inverted to ensure the positive x is to the
    // right. This is simply due to how the potentiometer on the joystick
    // I was using was connected up. It could have been corrected in hardware
    // by swapping the power supply pins. Instead it is done in software so may
    // need to be changed depending on your wiring setup

    Vector2D coord = {-x,y};
    return coord;
}

// This maps the raw x,y coord onto a circular grid.
// See:  http://mathproofs.blogspot.co.uk/2005/07/mapping-square-to-circle.html
Vector2D Gamepad::get_mapped_coord()
{
    Vector2D coord = get_coord();

    // do the transformation
    float x = coord.x*sqrt(1.0f-pow(coord.y,2.0f)/2.0f);
    float y = coord.y*sqrt(1.0f-pow(coord.x,2.0f)/2.0f);

    Vector2D mapped_coord = {x,y};
    return mapped_coord;
}

// this function converts the mapped coordinates into polar form
Polar Gamepad::get_polar()
{
    // get the mapped coordinate
    Vector2D coord = get_mapped_coord();

    // at this point, 0 degrees (i.e. x-axis) will be defined to the East.
    // We want 0 degrees to correspond to North and increase clockwise to 359
    // like a compass heading, so we need to swap the axis and invert y
    float x = coord.y;
    float y = coord.x;

    float mag = sqrt(x*x+y*y);  // pythagoras
    float angle = RAD2DEG*atan2(y,x);
    // angle will be in range -180 to 180, so add 360 to negative angles to
    // move to 0 to 360 range
    if (angle < 0.0f) {
        angle+=360.0f;
    }

    // the noise on the ADC causes the values of x and y to fluctuate slightly
    // around the centred values. This causes the random angle values to get
    // calculated when the joystick is centred and untouched. This is also when
    // the magnitude is very small, so we can check for a small magnitude and then
    // set the angle to -1. This will inform us when the angle is invalid and the
    // joystick is centred

    if (mag < TOL) {
        mag = 0.0f;
        angle = -1.0f;
    }

    Polar p = {mag,angle};
    return p;
}