ELEC2645 (2018/19) / Mbed 2 deprecated ml17z4c_attempt2

ZIYI CHEN ml17z4c 201214999

Dependencies:   mbed

Gamepad/Gamepad.cpp@2:3e4189eae232, 2019-03-19 (annotated)

Committer:
ziyi11
Date:
Tue Mar 19 09:26:43 2019 +0000
Revision:
2:3e4189eae232
Parent:
0:bf56f20b9c5a 
adder header;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ziyi11 0:bf56f20b9c5a 1 #include "Gamepad.h"
ziyi11 2:3e4189eae232 2 #include "N5110.h"
ziyi11 2:3e4189eae232 3
ziyi11 0:bf56f20b9c5a 4
ziyi11 0:bf56f20b9c5a 5 #include "mbed.h"
ziyi11 0:bf56f20b9c5a 6
ziyi11 0:bf56f20b9c5a 7 //////////// constructor/destructor ////////////
ziyi11 0:bf56f20b9c5a 8 Gamepad::Gamepad()
ziyi11 0:bf56f20b9c5a 9 :
ziyi11 0:bf56f20b9c5a 10 _led1(new PwmOut(PTA1)),
ziyi11 0:bf56f20b9c5a 11 _led2(new PwmOut(PTA2)),
ziyi11 0:bf56f20b9c5a 12 _led3(new PwmOut(PTC2)),
ziyi11 0:bf56f20b9c5a 13 _led4(new PwmOut(PTC3)),
ziyi11 0:bf56f20b9c5a 14 _led5(new PwmOut(PTC4)),
ziyi11 0:bf56f20b9c5a 15 _led6(new PwmOut(PTD3)),
ziyi11 0:bf56f20b9c5a 16
ziyi11 0:bf56f20b9c5a 17 _button_A(new InterruptIn(PTB9)),
ziyi11 0:bf56f20b9c5a 18 _button_B(new InterruptIn(PTD0)),
ziyi11 0:bf56f20b9c5a 19 _button_X(new InterruptIn(PTC17)),
ziyi11 0:bf56f20b9c5a 20 _button_Y(new InterruptIn(PTC12)),
ziyi11 0:bf56f20b9c5a 21 _button_L(new InterruptIn(PTB18)),
ziyi11 0:bf56f20b9c5a 22 _button_R(new InterruptIn(PTB3)),
ziyi11 0:bf56f20b9c5a 23 _button_back(new InterruptIn(PTB19)),
ziyi11 0:bf56f20b9c5a 24 _button_start(new InterruptIn(PTC5)),
ziyi11 0:bf56f20b9c5a 25 _button_joystick(new InterruptIn(PTC16)),
ziyi11 0:bf56f20b9c5a 26
ziyi11 0:bf56f20b9c5a 27 _vert(new AnalogIn(PTB10)),
ziyi11 0:bf56f20b9c5a 28 _horiz(new AnalogIn(PTB11)),
ziyi11 0:bf56f20b9c5a 29
ziyi11 0:bf56f20b9c5a 30 _buzzer(new PwmOut(PTC10)),
ziyi11 0:bf56f20b9c5a 31 _pot(new AnalogIn(PTB2)),
ziyi11 0:bf56f20b9c5a 32
ziyi11 0:bf56f20b9c5a 33 _timeout(new Timeout()),
ziyi11 0:bf56f20b9c5a 34
ziyi11 0:bf56f20b9c5a 35 _event_state(0),
ziyi11 0:bf56f20b9c5a 36
ziyi11 0:bf56f20b9c5a 37 _x0(0),
ziyi11 0:bf56f20b9c5a 38 _y0(0)
ziyi11 0:bf56f20b9c5a 39 {}
ziyi11 0:bf56f20b9c5a 40
ziyi11 0:bf56f20b9c5a 41 Gamepad::~Gamepad()
ziyi11 0:bf56f20b9c5a 42 {
ziyi11 0:bf56f20b9c5a 43 delete _led1,_led2,_led3,_led4,_led5,_led6;
ziyi11 0:bf56f20b9c5a 44 delete _button_A,_button_B,_button_joystick,_vert,_horiz;
ziyi11 0:bf56f20b9c5a 45 delete _button_X,_button_Y,_button_back,_button_start;
ziyi11 0:bf56f20b9c5a 46 delete _button_L,_button_R, _buzzer, _pot, _timeout;
ziyi11 0:bf56f20b9c5a 47 }
ziyi11 0:bf56f20b9c5a 48
ziyi11 0:bf56f20b9c5a 49 ///////////////// public methods /////////////////
ziyi11 0:bf56f20b9c5a 50
ziyi11 0:bf56f20b9c5a 51 void Gamepad::init()
ziyi11 0:bf56f20b9c5a 52 {
ziyi11 0:bf56f20b9c5a 53 leds_off();
ziyi11 0:bf56f20b9c5a 54 init_buttons();
ziyi11 0:bf56f20b9c5a 55
ziyi11 0:bf56f20b9c5a 56 // read centred values of joystick
ziyi11 0:bf56f20b9c5a 57 _x0 = _horiz->read();
ziyi11 0:bf56f20b9c5a 58 _y0 = _vert->read();
ziyi11 0:bf56f20b9c5a 59
ziyi11 0:bf56f20b9c5a 60 // clear all flags
ziyi11 0:bf56f20b9c5a 61 _event_state = 0;
ziyi11 0:bf56f20b9c5a 62 }
ziyi11 0:bf56f20b9c5a 63
ziyi11 0:bf56f20b9c5a 64 void Gamepad::leds_off()
ziyi11 0:bf56f20b9c5a 65 {
ziyi11 0:bf56f20b9c5a 66 leds(0.0);
ziyi11 0:bf56f20b9c5a 67 }
ziyi11 0:bf56f20b9c5a 68
ziyi11 0:bf56f20b9c5a 69 void Gamepad::leds_on()
ziyi11 0:bf56f20b9c5a 70 {
ziyi11 0:bf56f20b9c5a 71 leds(1.0);
ziyi11 0:bf56f20b9c5a 72 }
ziyi11 0:bf56f20b9c5a 73
ziyi11 0:bf56f20b9c5a 74 void Gamepad::leds(float val) const
ziyi11 0:bf56f20b9c5a 75 {
ziyi11 0:bf56f20b9c5a 76 if (val < 0.0f) {
ziyi11 0:bf56f20b9c5a 77 val = 0.0f;
ziyi11 0:bf56f20b9c5a 78 }
ziyi11 0:bf56f20b9c5a 79 if (val > 1.0f) {
ziyi11 0:bf56f20b9c5a 80 val = 1.0f;
ziyi11 0:bf56f20b9c5a 81 }
ziyi11 0:bf56f20b9c5a 82
ziyi11 0:bf56f20b9c5a 83 // leds are active-low, so subtract from 1.0
ziyi11 0:bf56f20b9c5a 84 // 0.0 corresponds to fully-off, 1.0 to fully-on
ziyi11 0:bf56f20b9c5a 85 val = 1.0f - val;
ziyi11 0:bf56f20b9c5a 86
ziyi11 0:bf56f20b9c5a 87 _led1->write(val);
ziyi11 0:bf56f20b9c5a 88 _led2->write(val);
ziyi11 0:bf56f20b9c5a 89 _led3->write(val);
ziyi11 0:bf56f20b9c5a 90 _led4->write(val);
ziyi11 0:bf56f20b9c5a 91 _led5->write(val);
ziyi11 0:bf56f20b9c5a 92 _led6->write(val);
ziyi11 0:bf56f20b9c5a 93 }
ziyi11 0:bf56f20b9c5a 94
ziyi11 0:bf56f20b9c5a 95 void Gamepad::led(int n,float val) const
ziyi11 0:bf56f20b9c5a 96 {
ziyi11 0:bf56f20b9c5a 97 // ensure they are within vlaid range
ziyi11 0:bf56f20b9c5a 98 if (val < 0.0f) {
ziyi11 0:bf56f20b9c5a 99 val = 0.0f;
ziyi11 0:bf56f20b9c5a 100 }
ziyi11 0:bf56f20b9c5a 101 if (val > 1.0f) {
ziyi11 0:bf56f20b9c5a 102 val = 1.0f;
ziyi11 0:bf56f20b9c5a 103 }
ziyi11 0:bf56f20b9c5a 104
ziyi11 0:bf56f20b9c5a 105 switch (n) {
ziyi11 0:bf56f20b9c5a 106
ziyi11 0:bf56f20b9c5a 107 // check for valid LED number and set value
ziyi11 0:bf56f20b9c5a 108
ziyi11 0:bf56f20b9c5a 109 case 1:
ziyi11 0:bf56f20b9c5a 110 _led1->write(1.0f-val); // active-low so subtract from 1
ziyi11 0:bf56f20b9c5a 111 break;
ziyi11 0:bf56f20b9c5a 112 case 2:
ziyi11 0:bf56f20b9c5a 113 _led2->write(1.0f-val); // active-low so subtract from 1
ziyi11 0:bf56f20b9c5a 114 break;
ziyi11 0:bf56f20b9c5a 115 case 3:
ziyi11 0:bf56f20b9c5a 116 _led3->write(1.0f-val); // active-low so subtract from 1
ziyi11 0:bf56f20b9c5a 117 break;
ziyi11 0:bf56f20b9c5a 118 case 4:
ziyi11 0:bf56f20b9c5a 119 _led4->write(1.0f-val); // active-low so subtract from 1
ziyi11 0:bf56f20b9c5a 120 break;
ziyi11 0:bf56f20b9c5a 121 case 5:
ziyi11 0:bf56f20b9c5a 122 _led5->write(1.0f-val); // active-low so subtract from 1
ziyi11 0:bf56f20b9c5a 123 break;
ziyi11 0:bf56f20b9c5a 124 case 6:
ziyi11 0:bf56f20b9c5a 125 _led6->write(1.0f-val); // active-low so subtract from 1
ziyi11 0:bf56f20b9c5a 126 break;
ziyi11 0:bf56f20b9c5a 127
ziyi11 0:bf56f20b9c5a 128 }
ziyi11 0:bf56f20b9c5a 129 }
ziyi11 0:bf56f20b9c5a 130
ziyi11 0:bf56f20b9c5a 131 float Gamepad::read_pot() const
ziyi11 0:bf56f20b9c5a 132 {
ziyi11 0:bf56f20b9c5a 133 return _pot->read();
ziyi11 0:bf56f20b9c5a 134 }
ziyi11 0:bf56f20b9c5a 135
ziyi11 0:bf56f20b9c5a 136 void Gamepad::tone(float frequency, float duration)
ziyi11 0:bf56f20b9c5a 137 {
ziyi11 0:bf56f20b9c5a 138 _buzzer->period(1.0f/frequency);
ziyi11 0:bf56f20b9c5a 139 _buzzer->write(0.5); // 50% duty cycle - square wave
ziyi11 0:bf56f20b9c5a 140 _timeout->attach(callback(this, &Gamepad::tone_off), duration );
ziyi11 0:bf56f20b9c5a 141 }
ziyi11 0:bf56f20b9c5a 142
ziyi11 0:bf56f20b9c5a 143 bool Gamepad::check_event(GamepadEvent const id)
ziyi11 0:bf56f20b9c5a 144 {
ziyi11 0:bf56f20b9c5a 145 // Check whether event flag is set
ziyi11 0:bf56f20b9c5a 146 if (_event_state[id]) {
ziyi11 0:bf56f20b9c5a 147 _event_state.reset(id); // clear flag
ziyi11 0:bf56f20b9c5a 148 return true;
ziyi11 0:bf56f20b9c5a 149 } else {
ziyi11 0:bf56f20b9c5a 150 return false;
ziyi11 0:bf56f20b9c5a 151 }
ziyi11 0:bf56f20b9c5a 152 }
ziyi11 0:bf56f20b9c5a 153
ziyi11 0:bf56f20b9c5a 154 // this method gets the magnitude of the joystick movement
ziyi11 0:bf56f20b9c5a 155 float Gamepad::get_mag()
ziyi11 0:bf56f20b9c5a 156 {
ziyi11 0:bf56f20b9c5a 157 Polar p = get_polar();
ziyi11 0:bf56f20b9c5a 158 return p.mag;
ziyi11 0:bf56f20b9c5a 159 }
ziyi11 0:bf56f20b9c5a 160
ziyi11 0:bf56f20b9c5a 161 // this method gets the angle of joystick movement (0 to 360, 0 North)
ziyi11 0:bf56f20b9c5a 162 float Gamepad::get_angle()
ziyi11 0:bf56f20b9c5a 163 {
ziyi11 0:bf56f20b9c5a 164 Polar p = get_polar();
ziyi11 0:bf56f20b9c5a 165 return p.angle;
ziyi11 0:bf56f20b9c5a 166 }
ziyi11 0:bf56f20b9c5a 167
ziyi11 0:bf56f20b9c5a 168 Direction Gamepad::get_direction()
ziyi11 0:bf56f20b9c5a 169 {
ziyi11 0:bf56f20b9c5a 170 float angle = get_angle(); // 0 to 360, -1 for centred
ziyi11 0:bf56f20b9c5a 171
ziyi11 0:bf56f20b9c5a 172 Direction d;
ziyi11 0:bf56f20b9c5a 173 // partition 360 into segments and check which segment the angle is in
ziyi11 0:bf56f20b9c5a 174 if (angle < 0.0f) {
ziyi11 0:bf56f20b9c5a 175 d = CENTRE; // check for -1.0 angle
ziyi11 0:bf56f20b9c5a 176 } else if (angle < 22.5f) { // then keep going in 45 degree increments
ziyi11 0:bf56f20b9c5a 177 d = N;
ziyi11 0:bf56f20b9c5a 178 } else if (angle < 67.5f) {
ziyi11 0:bf56f20b9c5a 179 d = NE;
ziyi11 0:bf56f20b9c5a 180 } else if (angle < 112.5f) {
ziyi11 0:bf56f20b9c5a 181 d = E;
ziyi11 0:bf56f20b9c5a 182 } else if (angle < 157.5f) {
ziyi11 0:bf56f20b9c5a 183 d = SE;
ziyi11 0:bf56f20b9c5a 184 } else if (angle < 202.5f) {
ziyi11 0:bf56f20b9c5a 185 d = S;
ziyi11 0:bf56f20b9c5a 186 } else if (angle < 247.5f) {
ziyi11 0:bf56f20b9c5a 187 d = SW;
ziyi11 0:bf56f20b9c5a 188 } else if (angle < 292.5f) {
ziyi11 0:bf56f20b9c5a 189 d = W;
ziyi11 0:bf56f20b9c5a 190 } else if (angle < 337.5f) {
ziyi11 0:bf56f20b9c5a 191 d = NW;
ziyi11 0:bf56f20b9c5a 192 } else {
ziyi11 0:bf56f20b9c5a 193 d = N;
ziyi11 0:bf56f20b9c5a 194 }
ziyi11 0:bf56f20b9c5a 195
ziyi11 0:bf56f20b9c5a 196 return d;
ziyi11 0:bf56f20b9c5a 197 }
ziyi11 0:bf56f20b9c5a 198
ziyi11 0:bf56f20b9c5a 199 ///////////////////// private methods ////////////////////////
ziyi11 0:bf56f20b9c5a 200
ziyi11 0:bf56f20b9c5a 201 void Gamepad::tone_off()
ziyi11 0:bf56f20b9c5a 202 {
ziyi11 0:bf56f20b9c5a 203 // called after timeout
ziyi11 0:bf56f20b9c5a 204 _buzzer->write(0.0);
ziyi11 0:bf56f20b9c5a 205 }
ziyi11 0:bf56f20b9c5a 206
ziyi11 0:bf56f20b9c5a 207 void Gamepad::init_buttons()
ziyi11 0:bf56f20b9c5a 208 {
ziyi11 0:bf56f20b9c5a 209 // turn on pull-downs as other side of button is connected to 3V3
ziyi11 0:bf56f20b9c5a 210 // button is 0 when not pressed and 1 when pressed
ziyi11 0:bf56f20b9c5a 211 _button_A->mode(PullDown);
ziyi11 0:bf56f20b9c5a 212 _button_B->mode(PullDown);
ziyi11 0:bf56f20b9c5a 213 _button_X->mode(PullDown);
ziyi11 0:bf56f20b9c5a 214 _button_Y->mode(PullDown);
ziyi11 0:bf56f20b9c5a 215 _button_back->mode(PullDown);
ziyi11 0:bf56f20b9c5a 216 _button_start->mode(PullDown);
ziyi11 0:bf56f20b9c5a 217 _button_L->mode(PullDown);
ziyi11 0:bf56f20b9c5a 218 _button_R->mode(PullDown);
ziyi11 0:bf56f20b9c5a 219 _button_joystick->mode(PullDown);
ziyi11 0:bf56f20b9c5a 220 // therefore setup rising edge interrupts
ziyi11 0:bf56f20b9c5a 221 _button_A->rise(callback(this,&Gamepad::a_isr));
ziyi11 0:bf56f20b9c5a 222 _button_B->rise(callback(this,&Gamepad::b_isr));
ziyi11 0:bf56f20b9c5a 223 _button_X->rise(callback(this,&Gamepad::x_isr));
ziyi11 0:bf56f20b9c5a 224 _button_Y->rise(callback(this,&Gamepad::y_isr));
ziyi11 0:bf56f20b9c5a 225 _button_L->rise(callback(this,&Gamepad::l_isr));
ziyi11 0:bf56f20b9c5a 226 _button_R->rise(callback(this,&Gamepad::r_isr));
ziyi11 0:bf56f20b9c5a 227 _button_start->rise(callback(this,&Gamepad::start_isr));
ziyi11 0:bf56f20b9c5a 228 _button_back->rise(callback(this,&Gamepad::back_isr));
ziyi11 0:bf56f20b9c5a 229 _button_joystick->rise(callback(this,&Gamepad::joy_isr));
ziyi11 0:bf56f20b9c5a 230 }
ziyi11 0:bf56f20b9c5a 231
ziyi11 0:bf56f20b9c5a 232 // button interrupts ISRs
ziyi11 0:bf56f20b9c5a 233 // Each of these simply sets the appropriate event bit in the _event_state
ziyi11 0:bf56f20b9c5a 234 // variable
ziyi11 0:bf56f20b9c5a 235 void Gamepad::a_isr()
ziyi11 0:bf56f20b9c5a 236 {
ziyi11 0:bf56f20b9c5a 237 _event_state.set(A_PRESSED);
ziyi11 0:bf56f20b9c5a 238 }
ziyi11 0:bf56f20b9c5a 239 void Gamepad::b_isr()
ziyi11 0:bf56f20b9c5a 240 {
ziyi11 0:bf56f20b9c5a 241 _event_state.set(B_PRESSED);
ziyi11 0:bf56f20b9c5a 242 }
ziyi11 0:bf56f20b9c5a 243 void Gamepad::x_isr()
ziyi11 0:bf56f20b9c5a 244 {
ziyi11 0:bf56f20b9c5a 245 _event_state.set(X_PRESSED);
ziyi11 0:bf56f20b9c5a 246 }
ziyi11 0:bf56f20b9c5a 247 void Gamepad::y_isr()
ziyi11 0:bf56f20b9c5a 248 {
ziyi11 0:bf56f20b9c5a 249 _event_state.set(Y_PRESSED);
ziyi11 0:bf56f20b9c5a 250 }
ziyi11 0:bf56f20b9c5a 251 void Gamepad::l_isr()
ziyi11 0:bf56f20b9c5a 252 {
ziyi11 0:bf56f20b9c5a 253 _event_state.set(L_PRESSED);
ziyi11 0:bf56f20b9c5a 254 }
ziyi11 0:bf56f20b9c5a 255 void Gamepad::r_isr()
ziyi11 0:bf56f20b9c5a 256 {
ziyi11 0:bf56f20b9c5a 257 _event_state.set(R_PRESSED);
ziyi11 0:bf56f20b9c5a 258 }
ziyi11 0:bf56f20b9c5a 259 void Gamepad::back_isr()
ziyi11 0:bf56f20b9c5a 260 {
ziyi11 0:bf56f20b9c5a 261 _event_state.set(BACK_PRESSED);
ziyi11 0:bf56f20b9c5a 262 }
ziyi11 0:bf56f20b9c5a 263 void Gamepad::start_isr()
ziyi11 0:bf56f20b9c5a 264 {
ziyi11 0:bf56f20b9c5a 265 _event_state.set(START_PRESSED);
ziyi11 0:bf56f20b9c5a 266 }
ziyi11 0:bf56f20b9c5a 267 void Gamepad::joy_isr()
ziyi11 0:bf56f20b9c5a 268 {
ziyi11 0:bf56f20b9c5a 269 _event_state.set(JOY_PRESSED);
ziyi11 0:bf56f20b9c5a 270 }
ziyi11 0:bf56f20b9c5a 271
ziyi11 0:bf56f20b9c5a 272 // get raw joystick coordinate in range -1 to 1
ziyi11 0:bf56f20b9c5a 273 // Direction (x,y)
ziyi11 0:bf56f20b9c5a 274 // North (0,1)
ziyi11 0:bf56f20b9c5a 275 // East (1,0)
ziyi11 0:bf56f20b9c5a 276 // South (0,-1)
ziyi11 0:bf56f20b9c5a 277 // West (-1,0)
ziyi11 0:bf56f20b9c5a 278 Vector2D Gamepad::get_coord()
ziyi11 0:bf56f20b9c5a 279 {
ziyi11 0:bf56f20b9c5a 280 // read() returns value in range 0.0 to 1.0 so is scaled and centre value
ziyi11 0:bf56f20b9c5a 281 // substracted to get values in the range -1.0 to 1.0
ziyi11 0:bf56f20b9c5a 282 float x = 2.0f*( _horiz->read() - _x0 );
ziyi11 0:bf56f20b9c5a 283 float y = 2.0f*( _vert->read() - _y0 );
ziyi11 0:bf56f20b9c5a 284
ziyi11 0:bf56f20b9c5a 285 // Note: the x value here is inverted to ensure the positive x is to the
ziyi11 0:bf56f20b9c5a 286 // right. This is simply due to how the potentiometer on the joystick
ziyi11 0:bf56f20b9c5a 287 // I was using was connected up. It could have been corrected in hardware
ziyi11 0:bf56f20b9c5a 288 // by swapping the power supply pins. Instead it is done in software so may
ziyi11 0:bf56f20b9c5a 289 // need to be changed depending on your wiring setup
ziyi11 0:bf56f20b9c5a 290
ziyi11 0:bf56f20b9c5a 291 Vector2D coord = {-x,y};
ziyi11 0:bf56f20b9c5a 292 return coord;
ziyi11 0:bf56f20b9c5a 293 }
ziyi11 0:bf56f20b9c5a 294
ziyi11 0:bf56f20b9c5a 295 // This maps the raw x,y coord onto a circular grid.
ziyi11 0:bf56f20b9c5a 296 // See: http://mathproofs.blogspot.co.uk/2005/07/mapping-square-to-circle.html
ziyi11 0:bf56f20b9c5a 297 Vector2D Gamepad::get_mapped_coord()
ziyi11 0:bf56f20b9c5a 298 {
ziyi11 0:bf56f20b9c5a 299 Vector2D coord = get_coord();
ziyi11 0:bf56f20b9c5a 300
ziyi11 0:bf56f20b9c5a 301 // do the transformation
ziyi11 0:bf56f20b9c5a 302 float x = coord.x*sqrt(1.0f-pow(coord.y,2.0f)/2.0f);
ziyi11 0:bf56f20b9c5a 303 float y = coord.y*sqrt(1.0f-pow(coord.x,2.0f)/2.0f);
ziyi11 0:bf56f20b9c5a 304
ziyi11 0:bf56f20b9c5a 305 Vector2D mapped_coord = {x,y};
ziyi11 0:bf56f20b9c5a 306 return mapped_coord;
ziyi11 0:bf56f20b9c5a 307 }
ziyi11 0:bf56f20b9c5a 308
ziyi11 0:bf56f20b9c5a 309 // this function converts the mapped coordinates into polar form
ziyi11 0:bf56f20b9c5a 310 Polar Gamepad::get_polar()
ziyi11 0:bf56f20b9c5a 311 {
ziyi11 0:bf56f20b9c5a 312 // get the mapped coordinate
ziyi11 0:bf56f20b9c5a 313 Vector2D coord = get_mapped_coord();
ziyi11 0:bf56f20b9c5a 314
ziyi11 0:bf56f20b9c5a 315 // at this point, 0 degrees (i.e. x-axis) will be defined to the East.
ziyi11 0:bf56f20b9c5a 316 // We want 0 degrees to correspond to North and increase clockwise to 359
ziyi11 0:bf56f20b9c5a 317 // like a compass heading, so we need to swap the axis and invert y
ziyi11 0:bf56f20b9c5a 318 float x = coord.y;
ziyi11 0:bf56f20b9c5a 319 float y = coord.x;
ziyi11 0:bf56f20b9c5a 320
ziyi11 0:bf56f20b9c5a 321 float mag = sqrt(x*x+y*y); // pythagoras
ziyi11 0:bf56f20b9c5a 322 float angle = RAD2DEG*atan2(y,x);
ziyi11 0:bf56f20b9c5a 323 // angle will be in range -180 to 180, so add 360 to negative angles to
ziyi11 0:bf56f20b9c5a 324 // move to 0 to 360 range
ziyi11 0:bf56f20b9c5a 325 if (angle < 0.0f) {
ziyi11 0:bf56f20b9c5a 326 angle+=360.0f;
ziyi11 0:bf56f20b9c5a 327 }
ziyi11 0:bf56f20b9c5a 328
ziyi11 0:bf56f20b9c5a 329 // the noise on the ADC causes the values of x and y to fluctuate slightly
ziyi11 0:bf56f20b9c5a 330 // around the centred values. This causes the random angle values to get
ziyi11 0:bf56f20b9c5a 331 // calculated when the joystick is centred and untouched. This is also when
ziyi11 0:bf56f20b9c5a 332 // the magnitude is very small, so we can check for a small magnitude and then
ziyi11 0:bf56f20b9c5a 333 // set the angle to -1. This will inform us when the angle is invalid and the
ziyi11 0:bf56f20b9c5a 334 // joystick is centred
ziyi11 0:bf56f20b9c5a 335
ziyi11 0:bf56f20b9c5a 336 if (mag < TOL) {
ziyi11 0:bf56f20b9c5a 337 mag = 0.0f;
ziyi11 0:bf56f20b9c5a 338 angle = -1.0f;
ziyi11 0:bf56f20b9c5a 339 }
ziyi11 0:bf56f20b9c5a 340
ziyi11 0:bf56f20b9c5a 341 Polar p = {mag,angle};
ziyi11 0:bf56f20b9c5a 342 return p;
ziyi11 0:bf56f20b9c5a 343 }