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@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.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 2:c9f2a9e2f304 110 void button_fall_isr();
avi23 0:56a82b52e0d4 111 void button_debounce_isr();
avi23 1:78d3e8b50d19 112 private:
avi23 0:56a82b52e0d4 113 //Pin inputs
avi23 0:56a82b52e0d4 114 AnalogIn* x_axis_;
avi23 0:56a82b52e0d4 115 AnalogIn* y_axis_;
avi23 0:56a82b52e0d4 116 InterruptIn* button_;
avi23 0:56a82b52e0d4 117
avi23 0:56a82b52e0d4 118 //Ticker to prevent joystick button bounce
avi23 0:56a82b52e0d4 119 Timeout* button_debounce_;
avi23 0:56a82b52e0d4 120
avi23 0:56a82b52e0d4 121 //Stores X and Y offsets
avi23 0:56a82b52e0d4 122 float x_offset_;
avi23 0:56a82b52e0d4 123 float y_offset_;
avi23 0:56a82b52e0d4 124
avi23 0:56a82b52e0d4 125 //Stores interrupt flags
avi23 0:56a82b52e0d4 126 volatile bool g_button_flag_;
avi23 0:56a82b52e0d4 127 volatile bool g_button_debounce_flag_;
avi23 1:78d3e8b50d19 128 };
avi23 1:78d3e8b50d19 129
avi23 1:78d3e8b50d19 130 #endif