Pallavi Prasad / PS2

PS/2 Keyboard

Dependents:   Hangman

PS2KB.cpp@0:62b62530a82f, 2012-10-11 (annotated)

Committer:
pprasad7
Date:
Thu Oct 11 20:15:09 2012 +0000
Revision:
0:62b62530a82f
PS/2 Input;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
pprasad7 0:62b62530a82f 1 /**
pprasad7 0:62b62530a82f 2 * PS/2 keyboard interface control class (Version 0.0.1)
pprasad7 0:62b62530a82f 3 *
pprasad7 0:62b62530a82f 4 * Copyright (C) 2010 Shinichiro Nakamura (CuBeatSystems)
pprasad7 0:62b62530a82f 5 * http://shinta.main.jp/
pprasad7 0:62b62530a82f 6 */
pprasad7 0:62b62530a82f 7
pprasad7 0:62b62530a82f 8 #include "PS2KB.h"
pprasad7 0:62b62530a82f 9
pprasad7 0:62b62530a82f 10 /**
pprasad7 0:62b62530a82f 11 * Create.
pprasad7 0:62b62530a82f 12 *
pprasad7 0:62b62530a82f 13 * @param clk_pin Clock pin.
pprasad7 0:62b62530a82f 14 * @param dat_pin Data pin.
pprasad7 0:62b62530a82f 15 */
pprasad7 0:62b62530a82f 16 PS2KB::PS2KB(PinName clk_pin, PinName dat_pin)
pprasad7 0:62b62530a82f 17 : clk(clk_pin), dat(dat_pin) {
pprasad7 0:62b62530a82f 18 init_work();
pprasad7 0:62b62530a82f 19 clk.fall(this, &PS2KB::func_fall);
pprasad7 0:62b62530a82f 20 timeout = 1;
pprasad7 0:62b62530a82f 21 }
pprasad7 0:62b62530a82f 22
pprasad7 0:62b62530a82f 23 /**
pprasad7 0:62b62530a82f 24 * Destory.
pprasad7 0:62b62530a82f 25 */
pprasad7 0:62b62530a82f 26 PS2KB::~PS2KB() {
pprasad7 0:62b62530a82f 27 wdt.detach();
pprasad7 0:62b62530a82f 28 }
pprasad7 0:62b62530a82f 29
pprasad7 0:62b62530a82f 30 /**
pprasad7 0:62b62530a82f 31 * Get a data from a PS/2 device.
pprasad7 0:62b62530a82f 32 *
pprasad7 0:62b62530a82f 33 * @return A data from a PS/2 device.
pprasad7 0:62b62530a82f 34 */
pprasad7 0:62b62530a82f 35 int PS2KB::getc() {
pprasad7 0:62b62530a82f 36 tot.reset();
pprasad7 0:62b62530a82f 37 tot.start();
pprasad7 0:62b62530a82f 38 while (work.cStart == work.cEnd) {
pprasad7 0:62b62530a82f 39 wait_ms(1);
pprasad7 0:62b62530a82f 40 if ((timeout > 0) && (tot.read_ms() > timeout)) {
pprasad7 0:62b62530a82f 41 // printf("Timeout occured.\n");
pprasad7 0:62b62530a82f 42 return EOF;
pprasad7 0:62b62530a82f 43 }
pprasad7 0:62b62530a82f 44 }
pprasad7 0:62b62530a82f 45 tot.stop();
pprasad7 0:62b62530a82f 46
pprasad7 0:62b62530a82f 47 char c = work.buffer[work.cStart++];
pprasad7 0:62b62530a82f 48 work.cStart = work.cStart % RINGBUFSIZ;
pprasad7 0:62b62530a82f 49
pprasad7 0:62b62530a82f 50 return c;
pprasad7 0:62b62530a82f 51 }
pprasad7 0:62b62530a82f 52
pprasad7 0:62b62530a82f 53 /**
pprasad7 0:62b62530a82f 54 * Set timeout.
pprasad7 0:62b62530a82f 55 *
pprasad7 0:62b62530a82f 56 * @param ms Timeout ms.
pprasad7 0:62b62530a82f 57 */
pprasad7 0:62b62530a82f 58 void PS2KB::setTimeout(int ms) {
pprasad7 0:62b62530a82f 59 timeout = ms;
pprasad7 0:62b62530a82f 60 }
pprasad7 0:62b62530a82f 61
pprasad7 0:62b62530a82f 62 void PS2KB::func_timeout(void) {
pprasad7 0:62b62530a82f 63 work.bitcnt = 0;
pprasad7 0:62b62530a82f 64 }
pprasad7 0:62b62530a82f 65
pprasad7 0:62b62530a82f 66 void PS2KB::func_fall(void) {
pprasad7 0:62b62530a82f 67 int oddpar = 0;
pprasad7 0:62b62530a82f 68 /*
pprasad7 0:62b62530a82f 69 */
pprasad7 0:62b62530a82f 70 switch (work.bitcnt) {
pprasad7 0:62b62530a82f 71 case 0:
pprasad7 0:62b62530a82f 72 /*
pprasad7 0:62b62530a82f 73 * Start bit.
pprasad7 0:62b62530a82f 74 */
pprasad7 0:62b62530a82f 75 if (dat.read() != 0) {
pprasad7 0:62b62530a82f 76 // printf("Illegal start bit condition.\n");
pprasad7 0:62b62530a82f 77 }
pprasad7 0:62b62530a82f 78 work.bitcnt++;
pprasad7 0:62b62530a82f 79 break;
pprasad7 0:62b62530a82f 80 case 9:
pprasad7 0:62b62530a82f 81 /*
pprasad7 0:62b62530a82f 82 * Parity bit.
pprasad7 0:62b62530a82f 83 */
pprasad7 0:62b62530a82f 84 for (int i = 0; i < 8; i++) {
pprasad7 0:62b62530a82f 85 if ((work.buffer[work.cEnd] & (1 << i)) != 0) {
pprasad7 0:62b62530a82f 86 oddpar++;
pprasad7 0:62b62530a82f 87 }
pprasad7 0:62b62530a82f 88 }
pprasad7 0:62b62530a82f 89 if (dat.read() == 1) {
pprasad7 0:62b62530a82f 90 oddpar++;
pprasad7 0:62b62530a82f 91 }
pprasad7 0:62b62530a82f 92 if ((oddpar % 2) != 1) {
pprasad7 0:62b62530a82f 93 // printf("Data parity error.\n");
pprasad7 0:62b62530a82f 94 }
pprasad7 0:62b62530a82f 95 work.bitcnt++;
pprasad7 0:62b62530a82f 96 break;
pprasad7 0:62b62530a82f 97 case 10:
pprasad7 0:62b62530a82f 98 /*
pprasad7 0:62b62530a82f 99 * Stop bit.
pprasad7 0:62b62530a82f 100 */
pprasad7 0:62b62530a82f 101 if (dat.read() != 1) {
pprasad7 0:62b62530a82f 102 // printf("Illegal stop bit condition.\n");
pprasad7 0:62b62530a82f 103 }
pprasad7 0:62b62530a82f 104 if (work.cStart != ((work.cEnd + 1) % RINGBUFSIZ)) {
pprasad7 0:62b62530a82f 105 work.cEnd++;
pprasad7 0:62b62530a82f 106 work.cEnd = work.cEnd % RINGBUFSIZ;
pprasad7 0:62b62530a82f 107 work.bitcnt = 0;
pprasad7 0:62b62530a82f 108 } else {
pprasad7 0:62b62530a82f 109 // printf("Buffer overrun.\n");
pprasad7 0:62b62530a82f 110 }
pprasad7 0:62b62530a82f 111 break;
pprasad7 0:62b62530a82f 112 default:
pprasad7 0:62b62530a82f 113 if ((1 <= work.bitcnt) && (work.bitcnt <= 8)) {
pprasad7 0:62b62530a82f 114 /*
pprasad7 0:62b62530a82f 115 * data bit.
pprasad7 0:62b62530a82f 116 */
pprasad7 0:62b62530a82f 117 if (dat.read() == 1) {
pprasad7 0:62b62530a82f 118 work.buffer[work.cEnd] |= (1 << (work.bitcnt - 1));
pprasad7 0:62b62530a82f 119 } else {
pprasad7 0:62b62530a82f 120 work.buffer[work.cEnd] &= ~(1 << (work.bitcnt - 1));
pprasad7 0:62b62530a82f 121 }
pprasad7 0:62b62530a82f 122 work.bitcnt++;
pprasad7 0:62b62530a82f 123 } else {
pprasad7 0:62b62530a82f 124 /*
pprasad7 0:62b62530a82f 125 * Illegal internal state.
pprasad7 0:62b62530a82f 126 */
pprasad7 0:62b62530a82f 127 // printf("Illegal internal state found.\n");
pprasad7 0:62b62530a82f 128 init_work();
pprasad7 0:62b62530a82f 129 }
pprasad7 0:62b62530a82f 130 break;
pprasad7 0:62b62530a82f 131 }
pprasad7 0:62b62530a82f 132 wdt.detach();
pprasad7 0:62b62530a82f 133 wdt.attach_us(this, &PS2KB::func_timeout, 250);
pprasad7 0:62b62530a82f 134 }
pprasad7 0:62b62530a82f 135
pprasad7 0:62b62530a82f 136 void PS2KB::init_work(void) {
pprasad7 0:62b62530a82f 137 work.bitcnt = 0;
pprasad7 0:62b62530a82f 138 work.cStart = 0;
pprasad7 0:62b62530a82f 139 work.cEnd = 0;
pprasad7 0:62b62530a82f 140 }