wu weilong / Mbed 2 deprecated frdm_gpio1

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Dependencies:   mbed

Gamepad/Gamepad.cpp@10:ae5f62a1e40e, 2019-05-08 (annotated)

Committer:
wuweilong
Date:
Wed May 08 20:08:17 2019 +0000
Revision:
10:ae5f62a1e40e
version1

Who changed what in which revision?

UserRevisionLine numberNew contents of line
wuweilong 10:ae5f62a1e40e 1 #include "Gamepad.h"
wuweilong 10:ae5f62a1e40e 2
wuweilong 10:ae5f62a1e40e 3 #include "mbed.h"
wuweilong 10:ae5f62a1e40e 4
wuweilong 10:ae5f62a1e40e 5 //////////// constructor/destructor ////////////
wuweilong 10:ae5f62a1e40e 6 Gamepad::Gamepad()
wuweilong 10:ae5f62a1e40e 7 :
wuweilong 10:ae5f62a1e40e 8 _led1(new PwmOut(PTA1)),
wuweilong 10:ae5f62a1e40e 9 _led2(new PwmOut(PTA2)),
wuweilong 10:ae5f62a1e40e 10 _led3(new PwmOut(PTC2)),
wuweilong 10:ae5f62a1e40e 11 _led4(new PwmOut(PTC3)),
wuweilong 10:ae5f62a1e40e 12 _led5(new PwmOut(PTC4)),
wuweilong 10:ae5f62a1e40e 13 _led6(new PwmOut(PTD3)),
wuweilong 10:ae5f62a1e40e 14
wuweilong 10:ae5f62a1e40e 15 _button_A(new InterruptIn(PTB9)),
wuweilong 10:ae5f62a1e40e 16 _button_B(new InterruptIn(PTD0)),
wuweilong 10:ae5f62a1e40e 17 _button_X(new InterruptIn(PTC17)),
wuweilong 10:ae5f62a1e40e 18 _button_Y(new InterruptIn(PTC12)),
wuweilong 10:ae5f62a1e40e 19 _button_L(new InterruptIn(PTB18)),
wuweilong 10:ae5f62a1e40e 20 _button_R(new InterruptIn(PTB3)),
wuweilong 10:ae5f62a1e40e 21 _button_back(new InterruptIn(PTB19)),
wuweilong 10:ae5f62a1e40e 22 _button_start(new InterruptIn(PTC5)),
wuweilong 10:ae5f62a1e40e 23 _button_joystick(new InterruptIn(PTC16)),
wuweilong 10:ae5f62a1e40e 24
wuweilong 10:ae5f62a1e40e 25 _vert(new AnalogIn(PTB10)),
wuweilong 10:ae5f62a1e40e 26 _horiz(new AnalogIn(PTB11)),
wuweilong 10:ae5f62a1e40e 27
wuweilong 10:ae5f62a1e40e 28 _buzzer(new PwmOut(PTC10)),
wuweilong 10:ae5f62a1e40e 29 _pot(new AnalogIn(PTB2)),
wuweilong 10:ae5f62a1e40e 30
wuweilong 10:ae5f62a1e40e 31 _timeout(new Timeout()),
wuweilong 10:ae5f62a1e40e 32
wuweilong 10:ae5f62a1e40e 33 _event_state(0),
wuweilong 10:ae5f62a1e40e 34
wuweilong 10:ae5f62a1e40e 35 _x0(0),
wuweilong 10:ae5f62a1e40e 36 _y0(0)
wuweilong 10:ae5f62a1e40e 37 {}
wuweilong 10:ae5f62a1e40e 38
wuweilong 10:ae5f62a1e40e 39 Gamepad::~Gamepad()
wuweilong 10:ae5f62a1e40e 40 {
wuweilong 10:ae5f62a1e40e 41 delete _led1,_led2,_led3,_led4,_led5,_led6;
wuweilong 10:ae5f62a1e40e 42 delete _button_A,_button_B,_button_joystick,_vert,_horiz;
wuweilong 10:ae5f62a1e40e 43 delete _button_X,_button_Y,_button_back,_button_start;
wuweilong 10:ae5f62a1e40e 44 delete _button_L,_button_R, _buzzer, _pot, _timeout;
wuweilong 10:ae5f62a1e40e 45 }
wuweilong 10:ae5f62a1e40e 46
wuweilong 10:ae5f62a1e40e 47 ///////////////// public methods /////////////////
wuweilong 10:ae5f62a1e40e 48
wuweilong 10:ae5f62a1e40e 49 void Gamepad::init()
wuweilong 10:ae5f62a1e40e 50 {
wuweilong 10:ae5f62a1e40e 51 leds_off();
wuweilong 10:ae5f62a1e40e 52 init_buttons();
wuweilong 10:ae5f62a1e40e 53
wuweilong 10:ae5f62a1e40e 54 // read centred values of joystick
wuweilong 10:ae5f62a1e40e 55 _x0 = _horiz->read();
wuweilong 10:ae5f62a1e40e 56 _y0 = _vert->read();
wuweilong 10:ae5f62a1e40e 57
wuweilong 10:ae5f62a1e40e 58 // clear all flags
wuweilong 10:ae5f62a1e40e 59 _event_state = 0;
wuweilong 10:ae5f62a1e40e 60 }
wuweilong 10:ae5f62a1e40e 61
wuweilong 10:ae5f62a1e40e 62 void Gamepad::leds_off()
wuweilong 10:ae5f62a1e40e 63 {
wuweilong 10:ae5f62a1e40e 64 leds(0.0);
wuweilong 10:ae5f62a1e40e 65 }
wuweilong 10:ae5f62a1e40e 66
wuweilong 10:ae5f62a1e40e 67 void Gamepad::leds_on()
wuweilong 10:ae5f62a1e40e 68 {
wuweilong 10:ae5f62a1e40e 69 leds(1.0);
wuweilong 10:ae5f62a1e40e 70 }
wuweilong 10:ae5f62a1e40e 71
wuweilong 10:ae5f62a1e40e 72 void Gamepad::leds(float val) const
wuweilong 10:ae5f62a1e40e 73 {
wuweilong 10:ae5f62a1e40e 74 if (val < 0.0f) {
wuweilong 10:ae5f62a1e40e 75 val = 0.0f;
wuweilong 10:ae5f62a1e40e 76 }
wuweilong 10:ae5f62a1e40e 77 if (val > 1.0f) {
wuweilong 10:ae5f62a1e40e 78 val = 1.0f;
wuweilong 10:ae5f62a1e40e 79 }
wuweilong 10:ae5f62a1e40e 80
wuweilong 10:ae5f62a1e40e 81 // leds are active-low, so subtract from 1.0
wuweilong 10:ae5f62a1e40e 82 // 0.0 corresponds to fully-off, 1.0 to fully-on
wuweilong 10:ae5f62a1e40e 83 val = 1.0f - val;
wuweilong 10:ae5f62a1e40e 84
wuweilong 10:ae5f62a1e40e 85 _led1->write(val);
wuweilong 10:ae5f62a1e40e 86 _led2->write(val);
wuweilong 10:ae5f62a1e40e 87 _led3->write(val);
wuweilong 10:ae5f62a1e40e 88 _led4->write(val);
wuweilong 10:ae5f62a1e40e 89 _led5->write(val);
wuweilong 10:ae5f62a1e40e 90 _led6->write(val);
wuweilong 10:ae5f62a1e40e 91 }
wuweilong 10:ae5f62a1e40e 92
wuweilong 10:ae5f62a1e40e 93 void Gamepad::led(int n,float val) const
wuweilong 10:ae5f62a1e40e 94 {
wuweilong 10:ae5f62a1e40e 95 // ensure they are within vlaid range
wuweilong 10:ae5f62a1e40e 96 if (val < 0.0f) {
wuweilong 10:ae5f62a1e40e 97 val = 0.0f;
wuweilong 10:ae5f62a1e40e 98 }
wuweilong 10:ae5f62a1e40e 99 if (val > 1.0f) {
wuweilong 10:ae5f62a1e40e 100 val = 1.0f;
wuweilong 10:ae5f62a1e40e 101 }
wuweilong 10:ae5f62a1e40e 102
wuweilong 10:ae5f62a1e40e 103 switch (n) {
wuweilong 10:ae5f62a1e40e 104
wuweilong 10:ae5f62a1e40e 105 // check for valid LED number and set value
wuweilong 10:ae5f62a1e40e 106
wuweilong 10:ae5f62a1e40e 107 case 1:
wuweilong 10:ae5f62a1e40e 108 _led1->write(1.0f-val); // active-low so subtract from 1
wuweilong 10:ae5f62a1e40e 109 break;
wuweilong 10:ae5f62a1e40e 110 case 2:
wuweilong 10:ae5f62a1e40e 111 _led2->write(1.0f-val); // active-low so subtract from 1
wuweilong 10:ae5f62a1e40e 112 break;
wuweilong 10:ae5f62a1e40e 113 case 3:
wuweilong 10:ae5f62a1e40e 114 _led3->write(1.0f-val); // active-low so subtract from 1
wuweilong 10:ae5f62a1e40e 115 break;
wuweilong 10:ae5f62a1e40e 116 case 4:
wuweilong 10:ae5f62a1e40e 117 _led4->write(1.0f-val); // active-low so subtract from 1
wuweilong 10:ae5f62a1e40e 118 break;
wuweilong 10:ae5f62a1e40e 119 case 5:
wuweilong 10:ae5f62a1e40e 120 _led5->write(1.0f-val); // active-low so subtract from 1
wuweilong 10:ae5f62a1e40e 121 break;
wuweilong 10:ae5f62a1e40e 122 case 6:
wuweilong 10:ae5f62a1e40e 123 _led6->write(1.0f-val); // active-low so subtract from 1
wuweilong 10:ae5f62a1e40e 124 break;
wuweilong 10:ae5f62a1e40e 125
wuweilong 10:ae5f62a1e40e 126 }
wuweilong 10:ae5f62a1e40e 127 }
wuweilong 10:ae5f62a1e40e 128
wuweilong 10:ae5f62a1e40e 129 float Gamepad::read_pot() const
wuweilong 10:ae5f62a1e40e 130 {
wuweilong 10:ae5f62a1e40e 131 return _pot->read();
wuweilong 10:ae5f62a1e40e 132 }
wuweilong 10:ae5f62a1e40e 133
wuweilong 10:ae5f62a1e40e 134 void Gamepad::tone(float frequency, float duration)
wuweilong 10:ae5f62a1e40e 135 {
wuweilong 10:ae5f62a1e40e 136 _buzzer->period(1.0f/frequency);
wuweilong 10:ae5f62a1e40e 137 _buzzer->write(0.5); // 50% duty cycle - square wave
wuweilong 10:ae5f62a1e40e 138 _timeout->attach(callback(this, &Gamepad::tone_off), duration );
wuweilong 10:ae5f62a1e40e 139 }
wuweilong 10:ae5f62a1e40e 140
wuweilong 10:ae5f62a1e40e 141 bool Gamepad::check_event(GamepadEvent const id)
wuweilong 10:ae5f62a1e40e 142 {
wuweilong 10:ae5f62a1e40e 143 // Check whether event flag is set
wuweilong 10:ae5f62a1e40e 144 if (_event_state[id]) {
wuweilong 10:ae5f62a1e40e 145 _event_state.reset(id); // clear flag
wuweilong 10:ae5f62a1e40e 146 return true;
wuweilong 10:ae5f62a1e40e 147 } else {
wuweilong 10:ae5f62a1e40e 148 return false;
wuweilong 10:ae5f62a1e40e 149 }
wuweilong 10:ae5f62a1e40e 150 }
wuweilong 10:ae5f62a1e40e 151
wuweilong 10:ae5f62a1e40e 152 // this method gets the magnitude of the joystick movement
wuweilong 10:ae5f62a1e40e 153 float Gamepad::get_mag()
wuweilong 10:ae5f62a1e40e 154 {
wuweilong 10:ae5f62a1e40e 155 Polar p = get_polar();
wuweilong 10:ae5f62a1e40e 156 return p.mag;
wuweilong 10:ae5f62a1e40e 157 }
wuweilong 10:ae5f62a1e40e 158
wuweilong 10:ae5f62a1e40e 159 // this method gets the angle of joystick movement (0 to 360, 0 North)
wuweilong 10:ae5f62a1e40e 160 float Gamepad::get_angle()
wuweilong 10:ae5f62a1e40e 161 {
wuweilong 10:ae5f62a1e40e 162 Polar p = get_polar();
wuweilong 10:ae5f62a1e40e 163 return p.angle;
wuweilong 10:ae5f62a1e40e 164 }
wuweilong 10:ae5f62a1e40e 165
wuweilong 10:ae5f62a1e40e 166 Direction Gamepad::get_direction()
wuweilong 10:ae5f62a1e40e 167 {
wuweilong 10:ae5f62a1e40e 168 float angle = get_angle(); // 0 to 360, -1 for centred
wuweilong 10:ae5f62a1e40e 169
wuweilong 10:ae5f62a1e40e 170 Direction d;
wuweilong 10:ae5f62a1e40e 171 // partition 360 into segments and check which segment the angle is in
wuweilong 10:ae5f62a1e40e 172 if (angle < 0.0f) {
wuweilong 10:ae5f62a1e40e 173 d = CENTRE; // check for -1.0 angle
wuweilong 10:ae5f62a1e40e 174 } else if (angle < 22.5f) { // then keep going in 45 degree increments
wuweilong 10:ae5f62a1e40e 175 d = N;
wuweilong 10:ae5f62a1e40e 176 } else if (angle < 67.5f) {
wuweilong 10:ae5f62a1e40e 177 d = NE;
wuweilong 10:ae5f62a1e40e 178 } else if (angle < 112.5f) {
wuweilong 10:ae5f62a1e40e 179 d = E;
wuweilong 10:ae5f62a1e40e 180 } else if (angle < 157.5f) {
wuweilong 10:ae5f62a1e40e 181 d = SE;
wuweilong 10:ae5f62a1e40e 182 } else if (angle < 202.5f) {
wuweilong 10:ae5f62a1e40e 183 d = S;
wuweilong 10:ae5f62a1e40e 184 } else if (angle < 247.5f) {
wuweilong 10:ae5f62a1e40e 185 d = SW;
wuweilong 10:ae5f62a1e40e 186 } else if (angle < 292.5f) {
wuweilong 10:ae5f62a1e40e 187 d = W;
wuweilong 10:ae5f62a1e40e 188 } else if (angle < 337.5f) {
wuweilong 10:ae5f62a1e40e 189 d = NW;
wuweilong 10:ae5f62a1e40e 190 } else {
wuweilong 10:ae5f62a1e40e 191 d = N;
wuweilong 10:ae5f62a1e40e 192 }
wuweilong 10:ae5f62a1e40e 193
wuweilong 10:ae5f62a1e40e 194 return d;
wuweilong 10:ae5f62a1e40e 195 }
wuweilong 10:ae5f62a1e40e 196
wuweilong 10:ae5f62a1e40e 197 ///////////////////// private methods ////////////////////////
wuweilong 10:ae5f62a1e40e 198
wuweilong 10:ae5f62a1e40e 199 void Gamepad::tone_off()
wuweilong 10:ae5f62a1e40e 200 {
wuweilong 10:ae5f62a1e40e 201 // called after timeout
wuweilong 10:ae5f62a1e40e 202 _buzzer->write(0.0);
wuweilong 10:ae5f62a1e40e 203 }
wuweilong 10:ae5f62a1e40e 204
wuweilong 10:ae5f62a1e40e 205 void Gamepad::init_buttons()
wuweilong 10:ae5f62a1e40e 206 {
wuweilong 10:ae5f62a1e40e 207 // turn on pull-downs as other side of button is connected to 3V3
wuweilong 10:ae5f62a1e40e 208 // button is 0 when not pressed and 1 when pressed
wuweilong 10:ae5f62a1e40e 209 _button_A->mode(PullDown);
wuweilong 10:ae5f62a1e40e 210 _button_B->mode(PullDown);
wuweilong 10:ae5f62a1e40e 211 _button_X->mode(PullDown);
wuweilong 10:ae5f62a1e40e 212 _button_Y->mode(PullDown);
wuweilong 10:ae5f62a1e40e 213 _button_back->mode(PullDown);
wuweilong 10:ae5f62a1e40e 214 _button_start->mode(PullDown);
wuweilong 10:ae5f62a1e40e 215 _button_L->mode(PullDown);
wuweilong 10:ae5f62a1e40e 216 _button_R->mode(PullDown);
wuweilong 10:ae5f62a1e40e 217 _button_joystick->mode(PullDown);
wuweilong 10:ae5f62a1e40e 218 // therefore setup rising edge interrupts
wuweilong 10:ae5f62a1e40e 219 _button_A->rise(callback(this,&Gamepad::a_isr));
wuweilong 10:ae5f62a1e40e 220 _button_B->rise(callback(this,&Gamepad::b_isr));
wuweilong 10:ae5f62a1e40e 221 _button_X->rise(callback(this,&Gamepad::x_isr));
wuweilong 10:ae5f62a1e40e 222 _button_Y->rise(callback(this,&Gamepad::y_isr));
wuweilong 10:ae5f62a1e40e 223 _button_L->rise(callback(this,&Gamepad::l_isr));
wuweilong 10:ae5f62a1e40e 224 _button_R->rise(callback(this,&Gamepad::r_isr));
wuweilong 10:ae5f62a1e40e 225 _button_start->rise(callback(this,&Gamepad::start_isr));
wuweilong 10:ae5f62a1e40e 226 _button_back->rise(callback(this,&Gamepad::back_isr));
wuweilong 10:ae5f62a1e40e 227 _button_joystick->rise(callback(this,&Gamepad::joy_isr));
wuweilong 10:ae5f62a1e40e 228 }
wuweilong 10:ae5f62a1e40e 229
wuweilong 10:ae5f62a1e40e 230 // button interrupts ISRs
wuweilong 10:ae5f62a1e40e 231 // Each of these simply sets the appropriate event bit in the _event_state
wuweilong 10:ae5f62a1e40e 232 // variable
wuweilong 10:ae5f62a1e40e 233 void Gamepad::a_isr()
wuweilong 10:ae5f62a1e40e 234 {
wuweilong 10:ae5f62a1e40e 235 _event_state.set(A_PRESSED);
wuweilong 10:ae5f62a1e40e 236 }
wuweilong 10:ae5f62a1e40e 237 void Gamepad::b_isr()
wuweilong 10:ae5f62a1e40e 238 {
wuweilong 10:ae5f62a1e40e 239 _event_state.set(B_PRESSED);
wuweilong 10:ae5f62a1e40e 240 }
wuweilong 10:ae5f62a1e40e 241 void Gamepad::x_isr()
wuweilong 10:ae5f62a1e40e 242 {
wuweilong 10:ae5f62a1e40e 243 _event_state.set(X_PRESSED);
wuweilong 10:ae5f62a1e40e 244 }
wuweilong 10:ae5f62a1e40e 245 void Gamepad::y_isr()
wuweilong 10:ae5f62a1e40e 246 {
wuweilong 10:ae5f62a1e40e 247 _event_state.set(Y_PRESSED);
wuweilong 10:ae5f62a1e40e 248 }
wuweilong 10:ae5f62a1e40e 249 void Gamepad::l_isr()
wuweilong 10:ae5f62a1e40e 250 {
wuweilong 10:ae5f62a1e40e 251 _event_state.set(L_PRESSED);
wuweilong 10:ae5f62a1e40e 252 }
wuweilong 10:ae5f62a1e40e 253 void Gamepad::r_isr()
wuweilong 10:ae5f62a1e40e 254 {
wuweilong 10:ae5f62a1e40e 255 _event_state.set(R_PRESSED);
wuweilong 10:ae5f62a1e40e 256 }
wuweilong 10:ae5f62a1e40e 257 void Gamepad::back_isr()
wuweilong 10:ae5f62a1e40e 258 {
wuweilong 10:ae5f62a1e40e 259 _event_state.set(BACK_PRESSED);
wuweilong 10:ae5f62a1e40e 260 }
wuweilong 10:ae5f62a1e40e 261 void Gamepad::start_isr()
wuweilong 10:ae5f62a1e40e 262 {
wuweilong 10:ae5f62a1e40e 263 _event_state.set(START_PRESSED);
wuweilong 10:ae5f62a1e40e 264 }
wuweilong 10:ae5f62a1e40e 265 void Gamepad::joy_isr()
wuweilong 10:ae5f62a1e40e 266 {
wuweilong 10:ae5f62a1e40e 267 _event_state.set(JOY_PRESSED);
wuweilong 10:ae5f62a1e40e 268 }
wuweilong 10:ae5f62a1e40e 269
wuweilong 10:ae5f62a1e40e 270 // get raw joystick coordinate in range -1 to 1
wuweilong 10:ae5f62a1e40e 271 // Direction (x,y)
wuweilong 10:ae5f62a1e40e 272 // North (0,1)
wuweilong 10:ae5f62a1e40e 273 // East (1,0)
wuweilong 10:ae5f62a1e40e 274 // South (0,-1)
wuweilong 10:ae5f62a1e40e 275 // West (-1,0)
wuweilong 10:ae5f62a1e40e 276 Vector2D Gamepad::get_coord()
wuweilong 10:ae5f62a1e40e 277 {
wuweilong 10:ae5f62a1e40e 278 // read() returns value in range 0.0 to 1.0 so is scaled and centre value
wuweilong 10:ae5f62a1e40e 279 // substracted to get values in the range -1.0 to 1.0
wuweilong 10:ae5f62a1e40e 280 float x = 2.0f*( _horiz->read() - _x0 );
wuweilong 10:ae5f62a1e40e 281 float y = 2.0f*( _vert->read() - _y0 );
wuweilong 10:ae5f62a1e40e 282
wuweilong 10:ae5f62a1e40e 283 // Note: the x value here is inverted to ensure the positive x is to the
wuweilong 10:ae5f62a1e40e 284 // right. This is simply due to how the potentiometer on the joystick
wuweilong 10:ae5f62a1e40e 285 // I was using was connected up. It could have been corrected in hardware
wuweilong 10:ae5f62a1e40e 286 // by swapping the power supply pins. Instead it is done in software so may
wuweilong 10:ae5f62a1e40e 287 // need to be changed depending on your wiring setup
wuweilong 10:ae5f62a1e40e 288
wuweilong 10:ae5f62a1e40e 289 Vector2D coord = {-x,y};
wuweilong 10:ae5f62a1e40e 290 return coord;
wuweilong 10:ae5f62a1e40e 291 }
wuweilong 10:ae5f62a1e40e 292
wuweilong 10:ae5f62a1e40e 293 // This maps the raw x,y coord onto a circular grid.
wuweilong 10:ae5f62a1e40e 294 // See: http://mathproofs.blogspot.co.uk/2005/07/mapping-square-to-circle.html
wuweilong 10:ae5f62a1e40e 295 Vector2D Gamepad::get_mapped_coord()
wuweilong 10:ae5f62a1e40e 296 {
wuweilong 10:ae5f62a1e40e 297 Vector2D coord = get_coord();
wuweilong 10:ae5f62a1e40e 298
wuweilong 10:ae5f62a1e40e 299 // do the transformation
wuweilong 10:ae5f62a1e40e 300 float x = coord.x*sqrt(1.0f-pow(coord.y,2.0f)/2.0f);
wuweilong 10:ae5f62a1e40e 301 float y = coord.y*sqrt(1.0f-pow(coord.x,2.0f)/2.0f);
wuweilong 10:ae5f62a1e40e 302
wuweilong 10:ae5f62a1e40e 303 Vector2D mapped_coord = {x,y};
wuweilong 10:ae5f62a1e40e 304 return mapped_coord;
wuweilong 10:ae5f62a1e40e 305 }
wuweilong 10:ae5f62a1e40e 306
wuweilong 10:ae5f62a1e40e 307 // this function converts the mapped coordinates into polar form
wuweilong 10:ae5f62a1e40e 308 Polar Gamepad::get_polar()
wuweilong 10:ae5f62a1e40e 309 {
wuweilong 10:ae5f62a1e40e 310 // get the mapped coordinate
wuweilong 10:ae5f62a1e40e 311 Vector2D coord = get_mapped_coord();
wuweilong 10:ae5f62a1e40e 312
wuweilong 10:ae5f62a1e40e 313 // at this point, 0 degrees (i.e. x-axis) will be defined to the East.
wuweilong 10:ae5f62a1e40e 314 // We want 0 degrees to correspond to North and increase clockwise to 359
wuweilong 10:ae5f62a1e40e 315 // like a compass heading, so we need to swap the axis and invert y
wuweilong 10:ae5f62a1e40e 316 float x = coord.y;
wuweilong 10:ae5f62a1e40e 317 float y = coord.x;
wuweilong 10:ae5f62a1e40e 318
wuweilong 10:ae5f62a1e40e 319 float mag = sqrt(x*x+y*y); // pythagoras
wuweilong 10:ae5f62a1e40e 320 float angle = RAD2DEG*atan2(y,x);
wuweilong 10:ae5f62a1e40e 321 // angle will be in range -180 to 180, so add 360 to negative angles to
wuweilong 10:ae5f62a1e40e 322 // move to 0 to 360 range
wuweilong 10:ae5f62a1e40e 323 if (angle < 0.0f) {
wuweilong 10:ae5f62a1e40e 324 angle+=360.0f;
wuweilong 10:ae5f62a1e40e 325 }
wuweilong 10:ae5f62a1e40e 326
wuweilong 10:ae5f62a1e40e 327 // the noise on the ADC causes the values of x and y to fluctuate slightly
wuweilong 10:ae5f62a1e40e 328 // around the centred values. This causes the random angle values to get
wuweilong 10:ae5f62a1e40e 329 // calculated when the joystick is centred and untouched. This is also when
wuweilong 10:ae5f62a1e40e 330 // the magnitude is very small, so we can check for a small magnitude and then
wuweilong 10:ae5f62a1e40e 331 // set the angle to -1. This will inform us when the angle is invalid and the
wuweilong 10:ae5f62a1e40e 332 // joystick is centred
wuweilong 10:ae5f62a1e40e 333
wuweilong 10:ae5f62a1e40e 334 if (mag < TOL) {
wuweilong 10:ae5f62a1e40e 335 mag = 0.0f;
wuweilong 10:ae5f62a1e40e 336 angle = -1.0f;
wuweilong 10:ae5f62a1e40e 337 }
wuweilong 10:ae5f62a1e40e 338
wuweilong 10:ae5f62a1e40e 339 Polar p = {mag,angle};
wuweilong 10:ae5f62a1e40e 340 return p;
wuweilong 10:ae5f62a1e40e 341 }