My ELEC2645 joystick project Tetris Game NAME: JIANWEI CHEN SID: 200879849
Dependencies: N5110 SDFileSystem mbed
Diff: Joystick.h
- Revision:
- 4:463abe5f5135
diff -r 5494a0fb3a33 -r 463abe5f5135 Joystick.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Joystick.h Thu May 05 09:18:01 2016 +0000 @@ -0,0 +1,92 @@ +/** +@file Joystick.h +@brief Header file containing functions prototypes, defines and global variables for constructing joystick. +@brief Example code of how to read a joystick with slightly changed for the game +@https://www.sparkfun.com/products/9032 +@author Craig A. Evans +@date 7 March 2015 +*/ + +#ifndef JOYSTICK_H +#define JOYSTICK_H + +#define DIRECTION_TOLERANCE 0.25 + +/** +Joystick vertical direction +@brief Analog input for joystick to send vertical directions data +*/ +AnalogIn yPot(PTB2); +/** +Joystick horizontal direction +@brief Analog input for joystick to send horizontal direction data +*/ +AnalogIn xPot(PTB3); + +//! create enumerated type (0,1,2,3 etc. for direction) +//! could be extended for diagonals etc. +enum DirectionName { + UP, + DOWN, + LEFT, + RIGHT, + CENTRE, + UNKNOWN +}; +//! struct for Joystick +typedef struct JoyStick Joystick; +struct JoyStick { + double x; // current x value + double x0; // 'centred' x value + double y; // current y value + double y0; // 'centred' y value + int button; // button state (assume pull-down used, so 1 = pressed, 0 = unpressed) + DirectionName direction; // current direction +}; +//! create struct variable +Joystick joystick; +/** +Read default positions of the joystick to calibrate later readings +*/ +void calibrateJoystick(); +/** +Update the current position of joystick +*/ +void updateJoystick(); + +///////////////////////////////////////////////// +/// Function Definitions +///////////////////////////////////////////////// + +// read default positions of the joystick to calibrate later readings +void calibrateJoystick() +{ + // must not move during calibration + joystick.x0 = xPot; // initial positions in the range 0.0 to 1.0 (0.5 if centred exactly) + joystick.y0 = yPot; +} + +void updateJoystick() +{ + // read current joystick values relative to calibrated values (in range -0.5 to 0.5, 0.0 is centred) + joystick.x = xPot - joystick.x0; + joystick.y = yPot - joystick.y0; + + // calculate direction depending on x,y values + // tolerance allows a little lee-way in case joystick not exactly in the stated direction + if ( fabs(joystick.y) < DIRECTION_TOLERANCE && fabs(joystick.x) < DIRECTION_TOLERANCE) { + joystick.direction = CENTRE; + } else if ( joystick.y < DIRECTION_TOLERANCE && fabs(joystick.x) < DIRECTION_TOLERANCE) { + joystick.direction = UP; + } else if ( joystick.y > DIRECTION_TOLERANCE && fabs(joystick.x) < DIRECTION_TOLERANCE) { + joystick.direction = DOWN; + } else if ( joystick.x < DIRECTION_TOLERANCE && fabs(joystick.y) < DIRECTION_TOLERANCE) { + joystick.direction = RIGHT; + } else if ( joystick.x > DIRECTION_TOLERANCE && fabs(joystick.y) < DIRECTION_TOLERANCE) { + joystick.direction = LEFT; + } else { + joystick.direction = UNKNOWN; + } +} + +#endif \ No newline at end of file