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@2:c9f2a9e2f304, 2016-05-05 (annotated)

Committer:
avi23
Date:
Thu May 05 11:00:46 2016 +0000
Revision:
2:c9f2a9e2f304
Parent:
1:78d3e8b50d19 
Changed debounce timeout to attach on the falling edge of the joystick. Prevents debounce when button is held down

Who changed what in which revision?

UserRevisionLine numberNew contents of line
avi23 1:78d3e8b50d19 1 /**
avi23 1:78d3e8b50d19 2 @file Joystick.cpp
avi23 1:78d3e8b50d19 3
avi23 1:78d3e8b50d19 4 @brief Member functions implementations
avi23 1:78d3e8b50d19 5
avi23 1:78d3e8b50d19 6 */
avi23 0:56a82b52e0d4 7 #include "Joystick.h"
avi23 0:56a82b52e0d4 8 #include "mbed.h"
avi23 0:56a82b52e0d4 9
avi23 2:c9f2a9e2f304 10 Joystick::Joystick(PinName x_axis_pin, PinName y_axis_pin, PinName button_pin)
avi23 2:c9f2a9e2f304 11 {
avi23 2:c9f2a9e2f304 12 x_axis_ = new AnalogIn(x_axis_pin);
avi23 2:c9f2a9e2f304 13 y_axis_ = new AnalogIn(y_axis_pin);
avi23 2:c9f2a9e2f304 14 button_ = new InterruptIn(button_pin);
avi23 2:c9f2a9e2f304 15 button_debounce_ = new Timeout();
avi23 0:56a82b52e0d4 16 }
avi23 0:56a82b52e0d4 17
avi23 2:c9f2a9e2f304 18 Joystick::~Joystick()
avi23 2:c9f2a9e2f304 19 {
avi23 2:c9f2a9e2f304 20 delete x_axis_;
avi23 2:c9f2a9e2f304 21 delete y_axis_;
avi23 2:c9f2a9e2f304 22 delete button_;
avi23 2:c9f2a9e2f304 23 delete button_debounce_;
avi23 0:56a82b52e0d4 24 }
avi23 0:56a82b52e0d4 25
avi23 2:c9f2a9e2f304 26 void Joystick::init()
avi23 2:c9f2a9e2f304 27 {
avi23 0:56a82b52e0d4 28 //Sets up the button ISR
avi23 2:c9f2a9e2f304 29 button_->mode(PullDown);
avi23 2:c9f2a9e2f304 30 button_->rise(this, &Joystick::button_isr);
avi23 2:c9f2a9e2f304 31 button_->fall(this, &Joystick::button_fall_isr);
avi23 0:56a82b52e0d4 32
avi23 0:56a82b52e0d4 33 //Initalises the vairables and flags
avi23 2:c9f2a9e2f304 34 x_offset_ = 0;
avi23 2:c9f2a9e2f304 35 y_offset_ = 0;
avi23 2:c9f2a9e2f304 36 g_button_flag_ = false;
avi23 2:c9f2a9e2f304 37 g_button_debounce_flag_ = false;
avi23 0:56a82b52e0d4 38
avi23 0:56a82b52e0d4 39 //Samples the joystick 5 times and takes an average to get the offset
avi23 2:c9f2a9e2f304 40 float x_sum = 0;
avi23 2:c9f2a9e2f304 41 float y_sum = 0;
avi23 0:56a82b52e0d4 42
avi23 2:c9f2a9e2f304 43 for (int i = 0; i < 5; ++i) {
avi23 2:c9f2a9e2f304 44 x_sum += x_axis_->read();
avi23 2:c9f2a9e2f304 45 y_sum += y_axis_->read();
avi23 2:c9f2a9e2f304 46 }
avi23 0:56a82b52e0d4 47
avi23 2:c9f2a9e2f304 48 x_offset_ = 0.5f - x_sum/5.0f;
avi23 2:c9f2a9e2f304 49 y_offset_ = 0.5f - y_sum/5.0f;
avi23 0:56a82b52e0d4 50 }
avi23 0:56a82b52e0d4 51
avi23 2:c9f2a9e2f304 52 float Joystick::GetXValue()
avi23 2:c9f2a9e2f304 53 {
avi23 0:56a82b52e0d4 54
avi23 2:c9f2a9e2f304 55 float x_sum = 0;
avi23 0:56a82b52e0d4 56 //Iterates 5 times and calculates an average
avi23 2:c9f2a9e2f304 57 for (int i = 0; i < 5; ++i) {
avi23 2:c9f2a9e2f304 58 x_sum += x_axis_->read();
avi23 2:c9f2a9e2f304 59 }
avi23 0:56a82b52e0d4 60
avi23 2:c9f2a9e2f304 61 float x_value = x_sum/5.0f + x_offset_;
avi23 0:56a82b52e0d4 62
avi23 0:56a82b52e0d4 63 //Caps the value for the POT between 0 and 1
avi23 2:c9f2a9e2f304 64 if (x_value < 0.0f) {
avi23 2:c9f2a9e2f304 65 return 0;
avi23 2:c9f2a9e2f304 66 } else if (x_value > 1.0f) {
avi23 2:c9f2a9e2f304 67 return 1;
avi23 2:c9f2a9e2f304 68 } else {
avi23 2:c9f2a9e2f304 69 return x_value;
avi23 2:c9f2a9e2f304 70 }
avi23 0:56a82b52e0d4 71 }
avi23 0:56a82b52e0d4 72
avi23 2:c9f2a9e2f304 73 float Joystick::GetYValue()
avi23 2:c9f2a9e2f304 74 {
avi23 0:56a82b52e0d4 75
avi23 2:c9f2a9e2f304 76 float y_sum = 0;
avi23 0:56a82b52e0d4 77 //Iterates 5 times and calculates an average
avi23 2:c9f2a9e2f304 78 for (int i = 0; i < 5; ++i) {
avi23 2:c9f2a9e2f304 79 y_sum += y_axis_->read();
avi23 2:c9f2a9e2f304 80 }
avi23 0:56a82b52e0d4 81
avi23 2:c9f2a9e2f304 82 float y_value = y_sum/5.0f + y_offset_;
avi23 0:56a82b52e0d4 83
avi23 0:56a82b52e0d4 84 //Caps the value for the POT between 0 and 1
avi23 2:c9f2a9e2f304 85 if (y_value < 0.0f) {
avi23 2:c9f2a9e2f304 86 return 0;
avi23 2:c9f2a9e2f304 87 } else if (y_value > 1.0f) {
avi23 2:c9f2a9e2f304 88 return 1;
avi23 2:c9f2a9e2f304 89 } else {
avi23 2:c9f2a9e2f304 90 return y_value;
avi23 2:c9f2a9e2f304 91 }
avi23 0:56a82b52e0d4 92 }
avi23 0:56a82b52e0d4 93
avi23 2:c9f2a9e2f304 94 int Joystick::get_button_flag()
avi23 2:c9f2a9e2f304 95 {
avi23 2:c9f2a9e2f304 96 return g_button_flag_;
avi23 0:56a82b52e0d4 97 }
avi23 0:56a82b52e0d4 98
avi23 2:c9f2a9e2f304 99 void Joystick::set_button_flag(bool value)
avi23 2:c9f2a9e2f304 100 {
avi23 2:c9f2a9e2f304 101 g_button_flag_ = value;
avi23 0:56a82b52e0d4 102 }
avi23 0:56a82b52e0d4 103
avi23 2:c9f2a9e2f304 104 void Joystick::button_isr()
avi23 2:c9f2a9e2f304 105 {
avi23 2:c9f2a9e2f304 106 if (!g_button_debounce_flag_) {
avi23 2:c9f2a9e2f304 107 g_button_flag_ = true;
avi23 2:c9f2a9e2f304 108 g_button_debounce_flag_ = true;
avi23 2:c9f2a9e2f304 109 }
avi23 0:56a82b52e0d4 110 }
avi23 0:56a82b52e0d4 111
avi23 2:c9f2a9e2f304 112 void Joystick::button_fall_isr()
avi23 2:c9f2a9e2f304 113 {
avi23 2:c9f2a9e2f304 114 button_debounce_->attach(this, &Joystick::button_debounce_isr, 0.125);
avi23 2:c9f2a9e2f304 115 }
avi23 2:c9f2a9e2f304 116
avi23 2:c9f2a9e2f304 117 void Joystick::button_debounce_isr()
avi23 2:c9f2a9e2f304 118 {
avi23 2:c9f2a9e2f304 119 g_button_debounce_flag_ = false;
avi23 0:56a82b52e0d4 120 }