Gert Jan Schoneveld / keypad

Fork without short circuits

Dependents:   SaveKeypad

Fork of keypad by HM Yoong

No extra hardware is needed besides the wires and switches. The columns are outputs configured with open drain. The rows are inputs configured with pull up resistors. A key press pulls down its row. With scanning the column is determined thereafter.

See SaveKeypad for an example usage.

keypad.h@5:45ab3e412893, 2012-01-30 (annotated)

Committer:
yoonghm
Date:
Mon Jan 30 10:03:56 2012 +0000
Revision:
5:45ab3e412893
Parent:
4:b24cd656a23d
Child:
6:8e4267765923
Documentation

Who changed what in which revision?

UserRevisionLine numberNew contents of line
yoonghm 0:2df66331c109 1 /* mbed Keypad library, using user-defined interrupt callback
yoonghm 0:2df66331c109 2 * Copyright (c) 2012 Yoong Hor Meng
yoonghm 0:2df66331c109 3 *
yoonghm 0:2df66331c109 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
yoonghm 0:2df66331c109 5 * of this software and associated documentation files (the "Software"), to deal
yoonghm 0:2df66331c109 6 * in the Software without restriction, including without limitation the rights
yoonghm 0:2df66331c109 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
yoonghm 0:2df66331c109 8 * copies of the Software, and to permit persons to whom the Software is
yoonghm 0:2df66331c109 9 * furnished to do so, subject to the following conditions:
yoonghm 0:2df66331c109 10 *
yoonghm 0:2df66331c109 11 * The above copyright notice and this permission notice shall be included in
yoonghm 0:2df66331c109 12 * all copies or substantial portions of the Software.
yoonghm 0:2df66331c109 13 *
yoonghm 0:2df66331c109 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
yoonghm 0:2df66331c109 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
yoonghm 0:2df66331c109 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
yoonghm 0:2df66331c109 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
yoonghm 0:2df66331c109 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
yoonghm 0:2df66331c109 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
yoonghm 0:2df66331c109 20 * THE SOFTWARE
yoonghm 0:2df66331c109 21 */
yoonghm 0:2df66331c109 22
yoonghm 0:2df66331c109 23 #ifndef KEYPAD_H
yoonghm 0:2df66331c109 24 #define KEYPAD_H
yoonghm 0:2df66331c109 25
yoonghm 0:2df66331c109 26 #include "mbed.h"
yoonghm 0:2df66331c109 27 #include "FPointer.h"
yoonghm 0:2df66331c109 28
yoonghm 0:2df66331c109 29 /**
yoonghm 1:b5eee44fa8a2 30 * An interrupt-based interface to 4x4 keypad.
yoonghm 4:b24cd656a23d 31 *
yoonghm 5:45ab3e412893 32 * You also need to import [[/cookbook/FPointer|FPointer library]] by Andy Kirkham
yoonghm 0:2df66331c109 33 * On each key pressed on a keypad, the index of the key is passed to a
yoonghm 0:2df66331c109 34 * user-defined function. User is free to define what to be done with the
yoonghm 0:2df66331c109 35 * input.
yoonghm 0:2df66331c109 36 *
yoonghm 2:2e4900821a28 37 * Example:
yoonghm 0:2df66331c109 38 * @code
yoonghm 2:2e4900821a28 39 * #include "mbed.h"
yoonghm 2:2e4900821a28 40 * #include "keypad.h"
yoonghm 2:2e4900821a28 41 *
yoonghm 2:2e4900821a28 42 * // Define your own keypad values
yoonghm 2:2e4900821a28 43 * char Keytable[] = { '1', '2', '3', 'A',
yoonghm 2:2e4900821a28 44 * '4', '5', '6', 'B',
yoonghm 2:2e4900821a28 45 * '7', '8', '9', 'C',
yoonghm 2:2e4900821a28 46 * '*', '0', '#', 'D'
yoonghm 2:2e4900821a28 47 * };
yoonghm 2:2e4900821a28 48 *
yoonghm 2:2e4900821a28 49 * uint32_t cbAfterInput(uint32_t index) {
yoonghm 2:2e4900821a28 50 * printf("Index:%d => Key:%c\n", key, Keytable[index]);
yoonghm 2:2e4900821a28 51 * return 0;
yoonghm 2:2e4900821a28 52 * }
yoonghm 2:2e4900821a28 53 *
yoonghm 2:2e4900821a28 54 * int main() {
yoonghm 2:2e4900821a28 55 * Keypad keypad(p25, p26, p27, p28, p21, p22, p23, p24);
yoonghm 2:2e4900821a28 56 * keypad.CallAfterInput(&cbAfterInput);
yoonghm 2:2e4900821a28 57 * keypad.Start();
yoonghm 2:2e4900821a28 58 *
yoonghm 2:2e4900821a28 59 * while (1) {
yoonghm 2:2e4900821a28 60 * wait_ms(100);
yoonghm 2:2e4900821a28 61 * }
yoonghm 2:2e4900821a28 62 * }
yoonghm 2:2e4900821a28 63 * @endcode
yoonghm 2:2e4900821a28 64 */
yoonghm 0:2df66331c109 65 class Keypad {
yoonghm 0:2df66331c109 66 public:
yoonghm 0:2df66331c109 67 /** Create a Keypad interface
yoonghm 0:2df66331c109 68 *
yoonghm 0:2df66331c109 69 * @param row<3..0> Row data lines
yoonghm 0:2df66331c109 70 * @param col<3..0> Column data lines
yoonghm 0:2df66331c109 71 * @param debounce_ms Debounce in ms (Default to 20ms)
yoonghm 0:2df66331c109 72 */
yoonghm 0:2df66331c109 73 Keypad(PinName row3, PinName row2, PinName row1, PinName row0,
yoonghm 0:2df66331c109 74 PinName col3, PinName col2, PinName col1, PinName col0,
yoonghm 0:2df66331c109 75 int debounce_ms = 20);
yoonghm 0:2df66331c109 76
yoonghm 0:2df66331c109 77 /** Start the keypad interrupt routines
yoonghm 0:2df66331c109 78 */
yoonghm 0:2df66331c109 79 void Start(void);
yoonghm 0:2df66331c109 80
yoonghm 0:2df66331c109 81 /** Stop the keypad interrupt routines
yoonghm 0:2df66331c109 82 */
yoonghm 0:2df66331c109 83 void Stop(void);
yoonghm 0:2df66331c109 84
yoonghm 0:2df66331c109 85 /** User-defined function that to be called when a key is pressed
yoonghm 0:2df66331c109 86 * @param fptr A function pointer takes a uint32_t and
yoonghm 0:2df66331c109 87 * returns uint32_t
yoonghm 0:2df66331c109 88 */
yoonghm 0:2df66331c109 89 void CallAfterInput(uint32_t (*fptr)(uint32_t));
yoonghm 0:2df66331c109 90
yoonghm 0:2df66331c109 91 protected:
yoonghm 0:2df66331c109 92 InterruptIn _row0;
yoonghm 0:2df66331c109 93 InterruptIn _row1;
yoonghm 0:2df66331c109 94 InterruptIn _row2;
yoonghm 0:2df66331c109 95 InterruptIn _row3;
yoonghm 0:2df66331c109 96 BusOut _cols;
yoonghm 0:2df66331c109 97 int _debounce;
yoonghm 0:2df66331c109 98 FPointer _input; // Called after each input
yoonghm 0:2df66331c109 99
yoonghm 0:2df66331c109 100 void _callback(int row, InterruptIn &therow);
yoonghm 0:2df66331c109 101 void _cbRow0Rise(void);
yoonghm 0:2df66331c109 102 void _cbRow1Rise(void);
yoonghm 0:2df66331c109 103 void _cbRow2Rise(void);
yoonghm 0:2df66331c109 104 void _cbRow3Rise(void);
yoonghm 0:2df66331c109 105 void _setupRiseTrigger(void);
yoonghm 0:2df66331c109 106 void _dummy(void) { };
yoonghm 0:2df66331c109 107 };
yoonghm 0:2df66331c109 108
yoonghm 0:2df66331c109 109 #endif // KEYPAD_H