| 1 | /* |
| 2 | |
| 3 | u8x8_debounce.c |
| 4 | |
| 5 | Key/button simple debounce algorithm (Addon for u8x8) |
| 6 | |
| 7 | Universal 8bit Graphics Library (https://github.com/olikraus/u8g2/) |
| 8 | |
| 9 | Copyright (c) 2016, olikraus@gmail.com |
| 10 | All rights reserved. |
| 11 | |
| 12 | Redistribution and use in source and binary forms, with or without modification, |
| 13 | are permitted provided that the following conditions are met: |
| 14 | |
| 15 | * Redistributions of source code must retain the above copyright notice, this list |
| 16 | of conditions and the following disclaimer. |
| 17 | |
| 18 | * Redistributions in binary form must reproduce the above copyright notice, this |
| 19 | list of conditions and the following disclaimer in the documentation and/or other |
| 20 | materials provided with the distribution. |
| 21 | |
| 22 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND |
| 23 | CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, |
| 24 | INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| 25 | MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| 26 | DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR |
| 27 | CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 28 | SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 29 | NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| 30 | LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| 31 | CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| 32 | STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 33 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| 34 | ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 35 | |
| 36 | */ |
| 37 | |
| 38 | #include "u8x8.h" |
| 39 | |
| 40 | static uint8_t u8x8_read_pin_state(u8x8_t *u8x8) |
| 41 | { |
| 42 | uint8_t i; |
| 43 | uint8_t pin_state; |
| 44 | |
| 45 | pin_state = 255; /* be compatible with the setup of the default pin setup, which is 255 */ |
| 46 | for( i = 0; i < U8X8_PIN_INPUT_CNT; i++ ) |
| 47 | { |
| 48 | pin_state <<= 1; |
| 49 | |
| 50 | /* the callback function should put the return value into this variable */ |
| 51 | u8x8->gpio_result = 1; |
| 52 | u8x8_gpio_call(u8x8, U8X8_MSG_GPIO(i+U8X8_PIN_OUTPUT_CNT), 0); |
| 53 | pin_state |= u8x8->gpio_result & 1; |
| 54 | } |
| 55 | |
| 56 | return pin_state; |
| 57 | } |
| 58 | |
| 59 | /* |
| 60 | return 0 to U8X8_PIN_INPUT_CNT-1 if there is a difference |
| 61 | return U8X8_PIN_INPUT_CNT if there is no difference |
| 62 | */ |
| 63 | static uint8_t u8x8_find_first_diff(uint8_t a, uint8_t b) |
| 64 | { |
| 65 | uint8_t mask; |
| 66 | uint8_t i; |
| 67 | mask = 1; |
| 68 | i = U8X8_PIN_INPUT_CNT; |
| 69 | do |
| 70 | { |
| 71 | i--; |
| 72 | if ( (a & mask) != (b & mask) ) |
| 73 | return i; |
| 74 | mask <<= 1; |
| 75 | } while( i > 0 ); |
| 76 | return U8X8_PIN_INPUT_CNT; |
| 77 | } |
| 78 | |
| 79 | /* |
| 80 | State A: |
| 81 | u8x8->debounce_last_pin_state == current_state |
| 82 | --> State A |
| 83 | u8x8->debounce_last_pin_state != current_state |
| 84 | --> u8x8->debounce_last_pin_state = current_state |
| 85 | --> State B + cnt |
| 86 | |
| 87 | State B + cnt |
| 88 | --> state-- |
| 89 | |
| 90 | State B |
| 91 | u8x8->debounce_last_pin_state == current_state |
| 92 | --> keypress detected |
| 93 | --> State C |
| 94 | u8x8->debounce_last_pin_state != current_state |
| 95 | --> State A |
| 96 | |
| 97 | State C |
| 98 | u8x8->debounce_last_pin_state == current_state |
| 99 | --> State C |
| 100 | u8x8->debounce_last_pin_state != current_state |
| 101 | --> State A |
| 102 | |
| 103 | */ |
| 104 | |
| 105 | #ifdef __unix__xxxxxx_THIS_IS_DISABLED |
| 106 | |
| 107 | #include <stdio.h> |
| 108 | #include <stdlib.h> |
| 109 | uint8_t u8x8_GetMenuEvent(u8x8_t *u8x8) |
| 110 | { |
| 111 | int c; |
| 112 | c = getc(stdin); |
| 113 | switch(c) |
| 114 | { |
| 115 | case 'n': |
| 116 | return U8X8_MSG_GPIO_MENU_NEXT; |
| 117 | case 'p': |
| 118 | return U8X8_MSG_GPIO_MENU_PREV; |
| 119 | case 's': |
| 120 | return U8X8_MSG_GPIO_MENU_SELECT; |
| 121 | case 'h': |
| 122 | return U8X8_MSG_GPIO_MENU_HOME; |
| 123 | case 'x': |
| 124 | exit(0); |
| 125 | default: |
| 126 | puts("press n, p, s, h or x"); |
| 127 | break; |
| 128 | } |
| 129 | return 0; |
| 130 | } |
| 131 | |
| 132 | |
| 133 | #else /* __unix__ */ |
| 134 | |
| 135 | |
| 136 | #define U8X8_DEBOUNCE_WAIT 2 |
| 137 | /* do debounce and return a GPIO msg which indicates the event */ |
| 138 | /* returns 0, if there is no event */ |
| 139 | #if defined(__GNUC__) && !defined(_WIN32) |
| 140 | # pragma weak u8x8_GetMenuEvent |
| 141 | #endif |
| 142 | uint8_t u8x8_GetMenuEvent(u8x8_t *u8x8) |
| 143 | { |
| 144 | uint8_t pin_state; |
| 145 | uint8_t result_msg = 0; /* invalid message, no event */ |
| 146 | |
| 147 | pin_state = u8x8_read_pin_state(u8x8); |
| 148 | |
| 149 | /* States A, B, C & D are encoded in the upper 4 bit*/ |
| 150 | switch(u8x8->debounce_state) |
| 151 | { |
| 152 | case 0x00: /* State A, default state */ |
| 153 | if ( u8x8->debounce_default_pin_state != pin_state ) |
| 154 | { |
| 155 | //u8x8->debounce_last_pin_state = pin_state; |
| 156 | u8x8->debounce_state = 0x010 + U8X8_DEBOUNCE_WAIT; |
| 157 | } |
| 158 | break; |
| 159 | case 0x10: /* State B */ |
| 160 | //if ( u8x8->debounce_last_pin_state != pin_state ) |
| 161 | if ( u8x8->debounce_default_pin_state == pin_state ) |
| 162 | { |
| 163 | u8x8->debounce_state = 0x00; /* back to state A */ |
| 164 | } |
| 165 | else |
| 166 | { |
| 167 | /* keypress detected */ |
| 168 | u8x8->debounce_last_pin_state = pin_state; |
| 169 | //result_msg = U8X8_MSG_GPIO_MENU_NEXT; |
| 170 | u8x8->debounce_state = 0x020 + U8X8_DEBOUNCE_WAIT; /* got to state C */ |
| 171 | } |
| 172 | break; |
| 173 | |
| 174 | case 0x20: /* State C */ |
| 175 | if ( u8x8->debounce_last_pin_state != pin_state ) |
| 176 | { |
| 177 | u8x8->debounce_state = 0x00; /* back to state A */ |
| 178 | } |
| 179 | else |
| 180 | { |
| 181 | u8x8->debounce_state = 0x030; /* got to state D */ |
| 182 | } |
| 183 | break; |
| 184 | |
| 185 | case 0x30: /* State D */ |
| 186 | /* wait until key release */ |
| 187 | if ( u8x8->debounce_default_pin_state == pin_state ) |
| 188 | { |
| 189 | u8x8->debounce_state = 0x00; /* back to state A */ |
| 190 | result_msg = U8X8_MSG_GPIO(u8x8_find_first_diff(u8x8->debounce_default_pin_state, u8x8->debounce_last_pin_state)+U8X8_PIN_OUTPUT_CNT); |
| 191 | } |
| 192 | else |
| 193 | { |
| 194 | //result_msg = U8X8_MSG_GPIO_MENU_NEXT; |
| 195 | // maybe implement autorepeat here |
| 196 | } |
| 197 | break; |
| 198 | default: |
| 199 | u8x8->debounce_state--; /* count down, until there is a valid state */ |
| 200 | break; |
| 201 | } |
| 202 | return result_msg; |
| 203 | } |
| 204 | |
| 205 | #endif /* __unix__ */ |