Joystick.cpp

00001 /*
00002 * N3310LCD. A program to interface mbed with the nuelectronics
00003 * Nokia 3310 LCD shield from www.nuelectronics.com. Ported from
00004 * the nuelectronics Arduino code.
00005 *
00006 * Copyright (C) <2009> Petras Saduikis <petras@petras.co.uk>
00007 *
00008 * Converted to a mbed library by Andrew D. Lindsay
00009 *
00010 * This file is part of N3310LCD.
00011 *
00012 * N3310LCD is free software: you can redistribute it and/or modify
00013 * it under the terms of the GNU General Public License as published by
00014 * the Free Software Foundation, either version 3 of the License, or
00015 * (at your option) any later version.
00016 *
00017 * N3310LCD is distributed in the hope that it will be useful,
00018 * but WITHOUT ANY WARRANTY; without even the implied warranty of
00019 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00020 * GNU General Public License for more details.
00021 *
00022 * You should have received a copy of the GNU General Public License
00023 * along with N3310LCD.  If not, see <http://www.gnu.org/licenses/>.
00024 */
00025 
00026 #include <mbed.h>
00027 #include "Joystick.h"
00028 
00029 //keypad debounce parameter
00030 #define DEBOUNCE_MAX 15
00031 #define DEBOUNCE_ON  10
00032 #define DEBOUNCE_OFF 3
00033 
00034 // values correspond to use of a 3.3V supply for the LCD shield.
00035 const int Joystick::adcKeyVal[NUM_KEYS] = {50,     // LEFT
00036         200,    // CENTER DEPRESSED
00037         400,    // DOWN
00038         600,    // UP
00039         800     // RIGHT
00040         // 1024 CENTER NOT DEPRESSED
00041                                           };
00042 
00043 Joystick::Joystick(PinName jstick) : joystick(jstick)
00044 {
00045     // reset button arrays
00046     for (int i = 0; i < NUM_KEYS; i++) {
00047         buttonCount[i] = 0;
00048         buttonStatus[i] = 0;
00049         buttonFlag[i] = 0;
00050     }
00051 }
00052 
00053 int Joystick::getKeyState(int i)
00054 {
00055     int retval = 0;
00056 
00057     if (i < NUM_KEYS) {
00058         retval = buttonFlag[i];
00059     }
00060 
00061     return retval;
00062 }
00063 
00064 void Joystick::resetKeyState(int i)
00065 {
00066     if (i < NUM_KEYS) {
00067         buttonFlag[i] = 0;
00068     }
00069 }
00070 
00071 void Joystick::updateADCKey()
00072 {
00073     // NOTE: the mbed analog in is 0 - 3.3V, represented as 0.0 - 1.0. It is important
00074     // that the LCD shield is powered from a 3.3V supply in order for the 'right' joystick
00075     // key to function correctly.
00076 
00077     int adcKeyIn = joystick * 1024;    // scale this up so we can use int
00078     int keyIn = getKey(adcKeyIn);
00079 
00080     for (int i = 0; i < NUM_KEYS; i++) {
00081         if (keyIn == i) { //one key is pressed
00082             if (buttonCount[i] < DEBOUNCE_MAX) {
00083                 buttonCount[i]++;
00084                 if (buttonCount[i] > DEBOUNCE_ON) {
00085                     if (buttonStatus[i] == 0) {
00086                         buttonFlag[i] = 1;
00087                         buttonStatus[i] = 1; //button debounced to 'pressed' status
00088                     }
00089                 }
00090             }
00091         } else { // no button pressed
00092             if (buttonCount[i] > 0) {
00093                 buttonFlag[i] = 0;
00094                 buttonCount[i]--;
00095                 if (buttonCount[i] < DEBOUNCE_OFF) {
00096                     buttonStatus[i] = 0;   //button debounced to 'released' status
00097                 }
00098             }
00099         }
00100     }
00101 }
00102 
00103 // Convert ADC value to key number
00104 int Joystick::getKey(int input)
00105 {
00106     int k;
00107 
00108     for (k = 0; k < NUM_KEYS; k++) {
00109         if (input < adcKeyVal[k]) return k;
00110     }
00111 
00112     if (k >= NUM_KEYS) k = -1;     // No valid key pressed
00113 
00114     return k;
00115 }