File content as of revision 0:c0833789892f:

/*
Initial prototyping to check hardware connections

Testing the following connections:

Joystick:
xPot            yPot            button
AnalogIn PTB11, AnalogIn PTB10, PTB9

Nokia 5110 lcd display: (Handled by library)
VCC    SCE   RST   D/C   MOSI  SCLK  LED
PTE26, PTA0, PTC4, PTD0, PTD2, PTD1, PTC3

buttonA    buttonB    g_led       buzzer
PTA1       PTB23      PWM PTC11   Undecided between AnalogOut DAC0_OUT or PWM PTC10 (decision will be based on sound quality)

01/03/16
By Joel W. Webb
Revision 1.0
*/

#include "mbed.h"
#include "N5110.h"

#define DIRECTION_TOLERANCE 0.05

// Nokia lcd object
//        VCC    SCE   RST   D/C   MOSI  SCLK  LED 
N5110 lcd(PTE26, PTA0, PTC4, PTD0, PTD2, PTD1, PTC3);

// Joystick
AnalogIn xPot(PTB11);
AnalogIn yPot(PTB10);
DigitalIn button(PTB9);

enum DirectionName {
    UP,
    DOWN,
    LEFT,
    RIGHT,
    CENTRE,
    UNKNOWN
};

// struct for Joystick
typedef struct JoyStick Joystick;
struct JoyStick {
    float x;    // current x value
    float x0;   // 'centred' x value
    float y;    // current y value
    float y0;   // 'centred' y value
    int button; // button state (assume pull-down used, so 1 = pressed, 0 = unpressed)
    DirectionName direction;  // current direction
};
// create struct variable
Joystick joystick;
Ticker pollJoystick; // Ticker interrput for polling the joystick

// Other inputs/outputs
InterruptIn buttonA(PTA1);
InterruptIn buttonB(PTB23);
PwmOut g_led(PTC11);
DigitalOut r_led(LED1); // Testing led

//Global Flags defined here
int g_joystick_flag;
int g_buttonA_flag;
int g_buttonB_flag;

// ISR defined here
void buttonA_isr(){
    g_buttonA_flag = 1;    
}
void buttonB_isr(){
    g_buttonB_flag = 1;    
}

// Functions defined here
void initInputs();
void updateJoystick();
void calibrateJoystick();

int main()
{
    initInputs();
    pollJoystick.attach(&updateJoystick,1.0/10.0);  // read joystick 10 times per second
    
    while (true) {
        
        if (g_buttonA_flag){
            g_buttonA_flag = 0;
            lcd.clear();
            lcd.printString("Button A",0,0);  
        }
        if (g_buttonB_flag){
            g_buttonB_flag = 0;
            lcd.clear();
            lcd.printString("Button B",0,1);    
        }
        if (g_joystick_flag){
            g_joystick_flag = 0;
            lcd.printString("            ",0,2);
            if (joystick.direction == 0){ lcd.printString("UP",0,2); }
            else if (joystick.direction == 1){ lcd.printString("DOWN",0,2); }
            else if (joystick.direction == 2){ lcd.printString("LEFT",0,2); }
            else if (joystick.direction == 3){ lcd.printString("RIGHT",0,2); }
            else if (joystick.direction == 4){ lcd.printString("CENTRE",0,2); }
            else if (joystick.direction == 5){ lcd.printString("UNDEFINED",0,2); }
            if (joystick.button){ lcd.printString("Button J",0,3); }
        }
        
        lcd.refresh();
        sleep();
        
    }
}



void initInputs(){
    
    r_led = 1;
    // Initialising power LED
    g_led.period(0.001); // Frequency of 1kHz
    g_led = 0.25; // Duty cycle of 0.25
    
    // Setting up Interrupt service routines for input buttons
    // Note no pull mode is specified so default pulldown resistors will be used
    buttonA.rise(&buttonA_isr);
    buttonB.rise(&buttonB_isr);
    buttonA.mode(PullDown);
    buttonB.mode(PullDown);
    
    
    //Testing LCD display works (splash screen)
    lcd.init();
    wait(1.0);
    lcd.printString("Calibrating",0,0);
    lcd.printString("Do not move",0,1);
    lcd.printString("Joystick",0,2);
    lcd.refresh();
    
    calibrateJoystick();

    wait(1.0);
    lcd.clear();

}

// read default positions of the joystick to calibrate later readings
void calibrateJoystick()
{
    button.mode(PullDown);
    // must not move during calibration
    joystick.x0 = xPot;  // initial positions in the range 0.0 to 1.0 (0.5 if centred exactly)
    joystick.y0 = yPot;
}
void updateJoystick()
{
    // read current joystick values relative to calibrated values (in range -0.5 to 0.5, 0.0 is centred)
    joystick.x = xPot - joystick.x0;
    joystick.y = yPot - joystick.y0;
    // read button state
    joystick.button = button;
 
    // calculate direction depending on x,y values
    // tolerance allows a little lee-way in case joystick not exactly in the stated direction
    if ( fabs(joystick.y) < DIRECTION_TOLERANCE && fabs(joystick.x) < DIRECTION_TOLERANCE) {
        joystick.direction = CENTRE;
    } else if ( joystick.y > DIRECTION_TOLERANCE && fabs(joystick.x) < DIRECTION_TOLERANCE) {
        joystick.direction = UP;
    } else if ( joystick.y < DIRECTION_TOLERANCE && fabs(joystick.x) < DIRECTION_TOLERANCE) {
        joystick.direction = DOWN;
    } else if ( joystick.x > DIRECTION_TOLERANCE && fabs(joystick.y) < DIRECTION_TOLERANCE) {
        joystick.direction = RIGHT;
    } else if ( joystick.x < DIRECTION_TOLERANCE && fabs(joystick.y) < DIRECTION_TOLERANCE) {
        joystick.direction = LEFT;
    } else {
        joystick.direction = UNKNOWN;
    }
 
    // set flag for printing
    g_joystick_flag = 1;
}