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.h@1:78d3e8b50d19, 2016-05-02 (annotated)

Committer:
avi23
Date:
Mon May 02 16:27:49 2016 +0000
Revision:
1:78d3e8b50d19
Parent:
0:56a82b52e0d4
Child:
2:c9f2a9e2f304
Documented using Doxygen

Who changed what in which revision?

UserRevisionLine numberNew contents of line
avi23 1:78d3e8b50d19 1 /**
avi23 1:78d3e8b50d19 2 @file Joystick.h
avi23 1:78d3e8b50d19 3 @brief Joysitck header file containing member functions and variables
avi23 1:78d3e8b50d19 4 */
avi23 0:56a82b52e0d4 5 //Joystick class - Header file
avi23 0:56a82b52e0d4 6 //Define guards
avi23 0:56a82b52e0d4 7 #ifndef JOYSTICK_H
avi23 0:56a82b52e0d4 8 #define JOYSTICK_H
avi23 0:56a82b52e0d4 9
avi23 0:56a82b52e0d4 10 #include "mbed.h"
avi23 0:56a82b52e0d4 11
avi23 1:78d3e8b50d19 12 /**
avi23 1:78d3e8b50d19 13 @brief Library for interfacing with a Joystick (http://proto-pic.co.uk/thumb-joystick-analogue/)
avi23 1:78d3e8b50d19 14 @brief Joystick is just 2 potentiometers and a button so can be interfaced with AnalogIn and DigitalIn/InterruptIn
avi23 1:78d3e8b50d19 15 @brief The library contains a method to prevent button debounce with a Timeout
avi23 1:78d3e8b50d19 16
avi23 1:78d3e8b50d19 17 @author Avinash Patel
avi23 1:78d3e8b50d19 18 @date April 2016
avi23 1:78d3e8b50d19 19 * Example
avi23 1:78d3e8b50d19 20 * @code
avi23 1:78d3e8b50d19 21
avi23 1:78d3e8b50d19 22 #include "mbed.h"
avi23 1:78d3e8b50d19 23 #include "Joystick.h"
avi23 1:78d3e8b50d19 24
avi23 1:78d3e8b50d19 25 // Xaxis,Yaxis,Button
avi23 1:78d3e8b50d19 26 Joystick joystick(PTB3, PTB2, PTB11);
avi23 1:78d3e8b50d19 27 DigitalOut r_led(LED_RED);
avi23 1:78d3e8b50d19 28 Serial pc(USBTX, USBRX);
avi23 1:78d3e8b50d19 29
avi23 1:78d3e8b50d19 30 int main()
avi23 1:78d3e8b50d19 31 {
avi23 1:78d3e8b50d19 32 //First initalise joystick
avi23 1:78d3e8b50d19 33 joystick.init();
avi23 1:78d3e8b50d19 34
avi23 1:78d3e8b50d19 35 while (true) {
avi23 1:78d3e8b50d19 36 //Stores x and y output values
avi23 1:78d3e8b50d19 37 float x, y;
avi23 1:78d3e8b50d19 38
avi23 1:78d3e8b50d19 39 //Calls the "GetXValue" and "GetYValue" and stores it in x and y
avi23 1:78d3e8b50d19 40 x = joystick.GetXValue();
avi23 1:78d3e8b50d19 41 y = joystick.GetYValue();
avi23 1:78d3e8b50d19 42
avi23 1:78d3e8b50d19 43 //Prints the values to the terminal
avi23 1:78d3e8b50d19 44 pc.printf("X: %f, Y: %f\n", x, y);
avi23 1:78d3e8b50d19 45
avi23 1:78d3e8b50d19 46 //If the button flag is pressed switch the led
avi23 1:78d3e8b50d19 47 if (joystick.get_button_flag()) {
avi23 1:78d3e8b50d19 48 r_led = !r_led
avi23 1:78d3e8b50d19 49 }
avi23 1:78d3e8b50d19 50 }
avi23 1:78d3e8b50d19 51 }
avi23 1:78d3e8b50d19 52 * @endcode
avi23 1:78d3e8b50d19 53 */
avi23 1:78d3e8b50d19 54
avi23 0:56a82b52e0d4 55 class Joystick
avi23 0:56a82b52e0d4 56 {
avi23 1:78d3e8b50d19 57 public:
avi23 1:78d3e8b50d19 58 /** Creates a Joystick object connected to the given pins
avi23 1:78d3e8b50d19 59 * Dynamically allocates AnalogIn for input potentiometers, InterruptIn for the joystick buton and the debounce Timeout
avi23 1:78d3e8b50d19 60 *
avi23 1:78d3e8b50d19 61 * @param x_axis_pin connected to the Joystick's x potentiometer output
avi23 1:78d3e8b50d19 62 * @param y_axis_pin connected to the Joystick's y potentiometer output
avi23 1:78d3e8b50d19 63 * @param button_pin connected to the Joystick's button
avi23 1:78d3e8b50d19 64 *
avi23 1:78d3e8b50d19 65 */
avi23 0:56a82b52e0d4 66 Joystick(PinName x_axis_pin, PinName y_axis_pin, PinName button_pin);
avi23 0:56a82b52e0d4 67
avi23 1:78d3e8b50d19 68 /** Destroys the Joystick object
avi23 1:78d3e8b50d19 69 * Clears the AnalogIn's, InterruptIn and Timeout from memory
avi23 1:78d3e8b50d19 70 */
avi23 0:56a82b52e0d4 71 ~Joystick();
avi23 0:56a82b52e0d4 72
avi23 1:78d3e8b50d19 73 /** Initalises the Joystick
avi23 1:78d3e8b50d19 74 * Sets up the InterruptIn Mode ISR
avi23 1:78d3e8b50d19 75 * Initalises the offset vairables and ISR flags
avi23 1:78d3e8b50d19 76 * Samples the AnalogIn's 5 times and takes an average to get the offset
avi23 1:78d3e8b50d19 77 */
avi23 0:56a82b52e0d4 78 void init();
avi23 0:56a82b52e0d4 79
avi23 1:78d3e8b50d19 80 /** Gets the value of the x potentiometer
avi23 1:78d3e8b50d19 81 * Takes 5 readings from the potentiometer
avi23 1:78d3e8b50d19 82 * Calculates the average measurement, accounting for joystick offset
avi23 1:78d3e8b50d19 83 * Caps the average between 0 and 1
avi23 1:78d3e8b50d19 84 *
avi23 1:78d3e8b50d19 85 * @returns the average value of the x potentiometer
avi23 1:78d3e8b50d19 86 */
avi23 0:56a82b52e0d4 87 float GetXValue();
avi23 0:56a82b52e0d4 88
avi23 1:78d3e8b50d19 89 /** Gets the value of the y potentiometer
avi23 1:78d3e8b50d19 90 * Takes 5 readings from the potentiometer
avi23 1:78d3e8b50d19 91 * Calculates the average measurement, accounting for joystick offset
avi23 1:78d3e8b50d19 92 * Caps the average between 0 and 1
avi23 1:78d3e8b50d19 93 *
avi23 1:78d3e8b50d19 94 * @returns the average value of the y potentiometer
avi23 1:78d3e8b50d19 95 */
avi23 0:56a82b52e0d4 96 float GetYValue();
avi23 0:56a82b52e0d4 97
avi23 1:78d3e8b50d19 98 /** Reads the state of the button flag
avi23 1:78d3e8b50d19 99 * @returns the button flag
avi23 1:78d3e8b50d19 100 */
avi23 0:56a82b52e0d4 101 int get_button_flag();
avi23 0:56a82b52e0d4 102
avi23 1:78d3e8b50d19 103 /** Sets the button flag
avi23 1:78d3e8b50d19 104 * @param value The value the flag will be set to
avi23 1:78d3e8b50d19 105 */
avi23 0:56a82b52e0d4 106 void set_button_flag(bool value);
avi23 0:56a82b52e0d4 107
avi23 1:78d3e8b50d19 108 private:
avi23 0:56a82b52e0d4 109 void button_isr();
avi23 0:56a82b52e0d4 110 void button_debounce_isr();
avi23 1:78d3e8b50d19 111 private:
avi23 0:56a82b52e0d4 112 //Pin inputs
avi23 0:56a82b52e0d4 113 AnalogIn* x_axis_;
avi23 0:56a82b52e0d4 114 AnalogIn* y_axis_;
avi23 0:56a82b52e0d4 115 InterruptIn* button_;
avi23 0:56a82b52e0d4 116
avi23 0:56a82b52e0d4 117 //Ticker to prevent joystick button bounce
avi23 0:56a82b52e0d4 118 Timeout* button_debounce_;
avi23 0:56a82b52e0d4 119
avi23 0:56a82b52e0d4 120 //Stores X and Y offsets
avi23 0:56a82b52e0d4 121 float x_offset_;
avi23 0:56a82b52e0d4 122 float y_offset_;
avi23 0:56a82b52e0d4 123
avi23 0:56a82b52e0d4 124 //Stores interrupt flags
avi23 0:56a82b52e0d4 125 volatile bool g_button_flag_;
avi23 0:56a82b52e0d4 126 volatile bool g_button_debounce_flag_;
avi23 1:78d3e8b50d19 127 };
avi23 1:78d3e8b50d19 128
avi23 1:78d3e8b50d19 129 #endif