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@1:b5eee44fa8a2, 2012-01-30 (annotated)

Committer:
yoonghm
Date:
Mon Jan 30 09:48:43 2012 +0000
Revision:
1:b5eee44fa8a2
Parent:
0:2df66331c109
Child:
2:2e4900821a28
Library dependency

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 1:b5eee44fa8a2 31 *
yoonghm 1:b5eee44fa8a2 32 * You also need to import FPointer library by Andy Kirkham
yoonghm 0:2df66331c109 33 *
yoonghm 0:2df66331c109 34 * On each key pressed on a keypad, the index of the key is passed to a
yoonghm 0:2df66331c109 35 * user-defined function. User is free to define what to be done with the
yoonghm 0:2df66331c109 36 * input.
yoonghm 0:2df66331c109 37 *
yoonghm 0:2df66331c109 38 *
yoonghm 0:2df66331c109 39 * @code
yoonghm 0:2df66331c109 40 *
yoonghm 0:2df66331c109 41 * #include "mbed.h"
yoonghm 0:2df66331c109 42 * #include "keypad.h"
yoonghm 0:2df66331c109 43 *
yoonghm 0:2df66331c109 44 * // Define your own keypad values
yoonghm 0:2df66331c109 45 * char Keytable[] = { '1', '2', '3', 'A',
yoonghm 0:2df66331c109 46 * '4', '5', '6', 'B',
yoonghm 0:2df66331c109 47 * '7', '8', '9', 'C',
yoonghm 0:2df66331c109 48 * '*', '0', '#', 'D'
yoonghm 0:2df66331c109 49 * };
yoonghm 0:2df66331c109 50 *
yoonghm 0:2df66331c109 51 * uint32_t cbAfterInput(uint32_t index) {
yoonghm 0:2df66331c109 52 * printf("Index:%d => Key:%c\n", key, Keytable[index]);
yoonghm 0:2df66331c109 53 * return 0;
yoonghm 0:2df66331c109 54 * }
yoonghm 0:2df66331c109 55 *
yoonghm 0:2df66331c109 56 * int main() {
yoonghm 0:2df66331c109 57 * Keypad keypad(p25, p26, p27, p28, p21, p22, p23, p24);
yoonghm 0:2df66331c109 58 * keypad.CallAfterInput(&cbAfterInput);
yoonghm 0:2df66331c109 59 * keypad.Start();
yoonghm 0:2df66331c109 60 *
yoonghm 0:2df66331c109 61 * while (1) {
yoonghm 0:2df66331c109 62 * wait_ms(100);
yoonghm 0:2df66331c109 63 * }
yoonghm 0:2df66331c109 64 * }
yoonghm 0:2df66331c109 65 * @endcode
yoonghm 0:2df66331c109 66 */
yoonghm 0:2df66331c109 67 class Keypad {
yoonghm 0:2df66331c109 68 public:
yoonghm 0:2df66331c109 69 /** Create a Keypad interface
yoonghm 0:2df66331c109 70 *
yoonghm 0:2df66331c109 71 * @param row<3..0> Row data lines
yoonghm 0:2df66331c109 72 * @param col<3..0> Column data lines
yoonghm 0:2df66331c109 73 * @param debounce_ms Debounce in ms (Default to 20ms)
yoonghm 0:2df66331c109 74 */
yoonghm 0:2df66331c109 75 Keypad(PinName row3, PinName row2, PinName row1, PinName row0,
yoonghm 0:2df66331c109 76 PinName col3, PinName col2, PinName col1, PinName col0,
yoonghm 0:2df66331c109 77 int debounce_ms = 20);
yoonghm 0:2df66331c109 78
yoonghm 0:2df66331c109 79 /** Start the keypad interrupt routines
yoonghm 0:2df66331c109 80 */
yoonghm 0:2df66331c109 81 void Start(void);
yoonghm 0:2df66331c109 82
yoonghm 0:2df66331c109 83 /** Stop the keypad interrupt routines
yoonghm 0:2df66331c109 84 */
yoonghm 0:2df66331c109 85 void Stop(void);
yoonghm 0:2df66331c109 86
yoonghm 0:2df66331c109 87 /** User-defined function that to be called when a key is pressed
yoonghm 0:2df66331c109 88 * @param fptr A function pointer takes a uint32_t and
yoonghm 0:2df66331c109 89 * returns uint32_t
yoonghm 0:2df66331c109 90 */
yoonghm 0:2df66331c109 91 void CallAfterInput(uint32_t (*fptr)(uint32_t));
yoonghm 0:2df66331c109 92
yoonghm 0:2df66331c109 93 protected:
yoonghm 0:2df66331c109 94 InterruptIn _row0;
yoonghm 0:2df66331c109 95 InterruptIn _row1;
yoonghm 0:2df66331c109 96 InterruptIn _row2;
yoonghm 0:2df66331c109 97 InterruptIn _row3;
yoonghm 0:2df66331c109 98 BusOut _cols;
yoonghm 0:2df66331c109 99 int _debounce;
yoonghm 0:2df66331c109 100 FPointer _input; // Called after each input
yoonghm 0:2df66331c109 101
yoonghm 0:2df66331c109 102 void _callback(int row, InterruptIn &therow);
yoonghm 0:2df66331c109 103 void _cbRow0Rise(void);
yoonghm 0:2df66331c109 104 void _cbRow1Rise(void);
yoonghm 0:2df66331c109 105 void _cbRow2Rise(void);
yoonghm 0:2df66331c109 106 void _cbRow3Rise(void);
yoonghm 0:2df66331c109 107 void _setupRiseTrigger(void);
yoonghm 0:2df66331c109 108 void _dummy(void) { };
yoonghm 0:2df66331c109 109 };
yoonghm 0:2df66331c109 110
yoonghm 0:2df66331c109 111 #endif // KEYPAD_H