ELEC2645 (2015/16) / Joystick

Gets potentiometer and button reading from a joystick (https://proto-pic.co.uk/thumb-joystick-analogue/)

Dependents:   L2_SpaceInvaders 6-Joystick

Joystick.cpp@0:56a82b52e0d4, 2016-04-28 (annotated)

Committer:
avi23
Date:
Thu Apr 28 14:14:22 2016 +0000
Revision:
0:56a82b52e0d4
Child:
1:78d3e8b50d19
First Commit - Joystick class from main converted to a library

Who changed what in which revision?

UserRevisionLine numberNew contents of line
avi23 0:56a82b52e0d4 1 //Joystick Class - Implementation
avi23 0:56a82b52e0d4 2 #include "Joystick.h"
avi23 0:56a82b52e0d4 3 #include "mbed.h"
avi23 0:56a82b52e0d4 4
avi23 0:56a82b52e0d4 5 Joystick::Joystick(PinName x_axis_pin, PinName y_axis_pin, PinName button_pin) {
avi23 0:56a82b52e0d4 6 x_axis_ = new AnalogIn(x_axis_pin);
avi23 0:56a82b52e0d4 7 y_axis_ = new AnalogIn(y_axis_pin);
avi23 0:56a82b52e0d4 8 button_ = new InterruptIn(button_pin);
avi23 0:56a82b52e0d4 9 button_debounce_ = new Timeout();
avi23 0:56a82b52e0d4 10 }
avi23 0:56a82b52e0d4 11
avi23 0:56a82b52e0d4 12 Joystick::~Joystick() {
avi23 0:56a82b52e0d4 13 delete x_axis_;
avi23 0:56a82b52e0d4 14 delete y_axis_;
avi23 0:56a82b52e0d4 15 delete button_;
avi23 0:56a82b52e0d4 16 delete button_debounce_;
avi23 0:56a82b52e0d4 17 }
avi23 0:56a82b52e0d4 18
avi23 0:56a82b52e0d4 19 void Joystick::init() {
avi23 0:56a82b52e0d4 20 //Sets up the button ISR
avi23 0:56a82b52e0d4 21 button_->mode(PullDown);
avi23 0:56a82b52e0d4 22 button_->rise(this, &Joystick::button_isr);
avi23 0:56a82b52e0d4 23
avi23 0:56a82b52e0d4 24 //Initalises the vairables and flags
avi23 0:56a82b52e0d4 25 x_offset_ = 0;
avi23 0:56a82b52e0d4 26 y_offset_ = 0;
avi23 0:56a82b52e0d4 27 g_button_flag_ = false;
avi23 0:56a82b52e0d4 28 g_button_debounce_flag_ = false;
avi23 0:56a82b52e0d4 29
avi23 0:56a82b52e0d4 30 //Samples the joystick 5 times and takes an average to get the offset
avi23 0:56a82b52e0d4 31 float x_sum = 0;
avi23 0:56a82b52e0d4 32 float y_sum = 0;
avi23 0:56a82b52e0d4 33
avi23 0:56a82b52e0d4 34 for (int i = 0; i < 5; ++i) {
avi23 0:56a82b52e0d4 35 x_sum += x_axis_->read();
avi23 0:56a82b52e0d4 36 y_sum += y_axis_->read();
avi23 0:56a82b52e0d4 37 }
avi23 0:56a82b52e0d4 38
avi23 0:56a82b52e0d4 39 x_offset_ = 0.5f - x_sum/5.0f;
avi23 0:56a82b52e0d4 40 y_offset_ = 0.5f - y_sum/5.0f;
avi23 0:56a82b52e0d4 41 }
avi23 0:56a82b52e0d4 42
avi23 0:56a82b52e0d4 43 float Joystick::GetXValue() {
avi23 0:56a82b52e0d4 44
avi23 0:56a82b52e0d4 45 float x_sum = 0;
avi23 0:56a82b52e0d4 46 //Iterates 5 times and calculates an average
avi23 0:56a82b52e0d4 47 for (int i = 0; i < 5; ++i) {
avi23 0:56a82b52e0d4 48 x_sum += x_axis_->read();
avi23 0:56a82b52e0d4 49 }
avi23 0:56a82b52e0d4 50
avi23 0:56a82b52e0d4 51 float x_value = x_sum/5.0f + x_offset_;
avi23 0:56a82b52e0d4 52
avi23 0:56a82b52e0d4 53 //Caps the value for the POT between 0 and 1
avi23 0:56a82b52e0d4 54 if (x_value < 0.0f) {
avi23 0:56a82b52e0d4 55 return 0;
avi23 0:56a82b52e0d4 56 } else if (x_value > 1.0f) {
avi23 0:56a82b52e0d4 57 return 1;
avi23 0:56a82b52e0d4 58 } else {
avi23 0:56a82b52e0d4 59 return x_value;
avi23 0:56a82b52e0d4 60 }
avi23 0:56a82b52e0d4 61 }
avi23 0:56a82b52e0d4 62
avi23 0:56a82b52e0d4 63 float Joystick::GetYValue() {
avi23 0:56a82b52e0d4 64
avi23 0:56a82b52e0d4 65 float y_sum = 0;
avi23 0:56a82b52e0d4 66 //Iterates 5 times and calculates an average
avi23 0:56a82b52e0d4 67 for (int i = 0; i < 5; ++i) {
avi23 0:56a82b52e0d4 68 y_sum += y_axis_->read();
avi23 0:56a82b52e0d4 69 }
avi23 0:56a82b52e0d4 70
avi23 0:56a82b52e0d4 71 float y_value = y_sum/5.0f + y_offset_;
avi23 0:56a82b52e0d4 72
avi23 0:56a82b52e0d4 73 //Caps the value for the POT between 0 and 1
avi23 0:56a82b52e0d4 74 if (y_value < 0.0f) {
avi23 0:56a82b52e0d4 75 return 0;
avi23 0:56a82b52e0d4 76 } else if (y_value > 1.0f) {
avi23 0:56a82b52e0d4 77 return 1;
avi23 0:56a82b52e0d4 78 } else {
avi23 0:56a82b52e0d4 79 return y_value;
avi23 0:56a82b52e0d4 80 }
avi23 0:56a82b52e0d4 81 }
avi23 0:56a82b52e0d4 82
avi23 0:56a82b52e0d4 83 int Joystick::get_button_flag() {
avi23 0:56a82b52e0d4 84 return g_button_flag_;
avi23 0:56a82b52e0d4 85 }
avi23 0:56a82b52e0d4 86
avi23 0:56a82b52e0d4 87 void Joystick::set_button_flag(bool value) {
avi23 0:56a82b52e0d4 88 g_button_flag_ = value;
avi23 0:56a82b52e0d4 89 }
avi23 0:56a82b52e0d4 90
avi23 0:56a82b52e0d4 91 void Joystick::button_isr() {
avi23 0:56a82b52e0d4 92 if (!g_button_debounce_flag_) {
avi23 0:56a82b52e0d4 93 g_button_flag_ = true;
avi23 0:56a82b52e0d4 94 g_button_debounce_flag_ = true;
avi23 0:56a82b52e0d4 95
avi23 0:56a82b52e0d4 96 //Sets up the debounce ticker to fire in 0.2s
avi23 0:56a82b52e0d4 97 button_debounce_->attach(this, &Joystick::button_debounce_isr, 0.2);
avi23 0:56a82b52e0d4 98 }
avi23 0:56a82b52e0d4 99 }
avi23 0:56a82b52e0d4 100
avi23 0:56a82b52e0d4 101 void Joystick::button_debounce_isr() {
avi23 0:56a82b52e0d4 102 g_button_debounce_flag_ = false;
avi23 0:56a82b52e0d4 103 }