annotate 1wire.c @ 9:7ed10c59ba06

Supply clock speed via the command line so 1wire-delay.h can use it.
author darius
date Mon, 12 Jul 2004 17:51:20 +0930
parents f9a085a0ba93
children eb1faf51968e
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1 /*
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2 * Various 1 wire routines
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3 * Search routine is copied from the Dallas owpd library with mods.
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4 *
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5 * $Id$
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6 *
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7 * Copyright (c) 2004
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8 * Daniel O'Connor <darius@dons.net.au>. All rights reserved.
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9 *
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10 * Redistribution and use in source and binary forms, with or without
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11 * modification, are permitted provided that the following conditions
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12 * are met:
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13 * 1. Redistributions of source code must retain the above copyright
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14 * notice, this list of conditions and the following disclaimer.
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15 * 2. Redistributions in binary form must reproduce the above copyright
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16 * notice, this list of conditions and the following disclaimer in the
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17 * documentation and/or other materials provided with the distribution.
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18 *
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19 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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22 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
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23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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29 * SUCH DAMAGE.
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30 */
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31
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32 #include <stdio.h>
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33 #include <avr/io.h>
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34 #include <avr/pgmspace.h>
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35
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36 #include "1wire.h"
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37 #include "1wire-delay.h"
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38
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39 void uart_putsP(const char *addr);
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40 void uart_puts(const char *addr);
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41 void uart_getc();
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42 int uart_putc(char c);
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43
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44 static uint8_t OW_LastDevice = 0;
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45 static uint8_t OW_LastDiscrepancy = 0;
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46 static uint8_t OW_LastFamilyDiscrepancy = 0;
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47
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48 static void
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49 OWdelay(void) {
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50 asm volatile (
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51 "ldi r21, 50\n\t"
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52 "_OWdelay:\n\t"
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53 "nop\n\t"
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54 "nop\n\t"
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55 "nop\n\t"
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56 "nop\n\t"
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57 "nop\n\t"
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58 "nop\n\t"
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59 "nop\n\t"
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60 "nop\n\t"
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61 "nop\n\t"
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62 "nop\n\t"
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63 "nop\n\t"
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64 "nop\n\t"
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65 "nop\n\t"
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66 "dec r21\n\t"
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67 "brne _OWdelay\n\t"
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68 ::: "r21");
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69 }
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70
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71 /*-----------------------------------------------------------------------------
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72 * Generate a 1-Wire reset, return 1 if no presence detect was found,
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73 * return 0 otherwise.
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74 * (NOTE: Does not handle alarm presence from DS2404/DS1994)
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75 */
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76 int
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77 OWTouchReset(void) {
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78 uint8_t result;
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79
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80 asm volatile (
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81 /* Delay G (0 usec) */
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82 "\n\t"
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83 /* Drive bus low */
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84 "cbi %[out], %[opin]\n\t"
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85 "sbi %[ddr], %[opin]\n\t"
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86 /* Delay H (480 usec) */
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87 "ldi r21, 120\n\t"
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88 "loopH:\n\t"
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89 "nop\n\t"
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90 "nop\n\t"
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91 "nop\n\t"
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92 "nop\n\t"
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93 "nop\n\t"
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94 "nop\n\t"
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95 "nop\n\t"
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96 "nop\n\t"
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97 "nop\n\t"
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98 "nop\n\t"
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99 "nop\n\t"
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100 "nop\n\t"
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101 "nop\n\t"
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102 "dec r21\n\t"
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103 "brne loopH\n\t"
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104 /* Release bus */
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105 "cbi %[ddr], %[opin]\n\t"
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106 /* Delay I (70 usec) */
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107 "ldi r21, 35\n\t"
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108 "loopI:\n\t"
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109 "nop\n\t"
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110 "nop\n\t"
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111 "nop\n\t"
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112 "nop\n\t"
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113 "nop\n\t"
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114 "dec r21\n\t"
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115 "brne loopI\n\t"
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116 /* Sample for presense */
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117 "ldi %[result], 0\n\t"
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118 "sbi %[ddr], 1\n\t"
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119 "sbi %[out], 1\n\t"
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120 /* 1 == no presence */
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121 "sbic %[in], %[ipin]\n\t"
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122 "ldi %[result], 1\n\t"
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123 "cbi %[out], 1\n\t"
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124
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125 : [result] "=r" (result) /* Outputs */
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126 : [out] "I" (_SFR_IO_ADDR(OWIREOUTPORT)), /* Inputs */
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127 [ddr] "I" (_SFR_IO_ADDR(OWIREDDR)),
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128 [opin] "I" (OWIREOUTPIN),
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129 [in] "I" (_SFR_IO_ADDR(OWIREINPORT)),
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130 [ipin] "I" (OWIREINPIN)
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131 : "r21"); /* Clobbers */
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132
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133 return(result);
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134 }
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135
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136 /*-----------------------------------------------------------------------------
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137 * Send a 1-wire write bit.
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138 */
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139 void
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140 OWWriteBit(int bit) {
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141 OWdelay();
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142 if (bit) {
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143 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN));
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144 OWIREDDR |= _BV(OWIREOUTPIN);
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145 DELAY_A;
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146 OWIREDDR &= ~(_BV(OWIREOUTPIN));
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147 DELAY_B;
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148 } else {
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149 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN));
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150 OWIREDDR |= _BV(OWIREOUTPIN);
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151 DELAY_C;
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152 OWIREDDR &= ~(_BV(OWIREOUTPIN));
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153 DELAY_D;
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154 }
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155 }
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156
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157 /*-----------------------------------------------------------------------------
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158 * Read a bit from the 1-wire bus and return it.
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159 */
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160 int
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161 OWReadBit(void) {
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162 OWdelay();
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163
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164 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN));
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165 OWIREDDR |= _BV(OWIREOUTPIN);
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166 DELAY_A;
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167 OWIREDDR &= ~(_BV(OWIREOUTPIN));
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168 DELAY_E;
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169 return(OWIREINPORT & _BV(OWIREINPIN) ? 1 : 0);
0
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170 }
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171
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172 /*-----------------------------------------------------------------------------
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173 * Write a byte to the 1-wire bus
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174 */
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175 void
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176 OWWriteByte(uint8_t data) {
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177 int i;
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178
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179 /* Send LSB first */
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180 for (i = 0; i < 8; i++) {
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181 OWWriteBit(data & 0x01);
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182 data >>= 1;
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183 }
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184 }
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185
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186 /*-----------------------------------------------------------------------------
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187 * Read a byte from the 1-wire bus
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188 */
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189 int
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190 OWReadByte(void) {
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191 int i, result = 0;
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192
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193 for (i = 0; i < 8; i++) {
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194 result >>= 1;
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195 if (OWReadBit())
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196 result |= 0x80;
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197 }
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198 return(result);
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199 }
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200
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201 /*-----------------------------------------------------------------------------
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202 * Write a 1-wire data byte and return the sampled result.
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203 */
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204 int
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205 OWTouchByte(uint8_t data) {
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206 int i, result = 0;
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207
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208 for (i = 0; i < 8; i++) {
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209 result >>= 1;
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210
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211 /* If sending a 1 then read a bit, otherwise write a 0 */
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212 if (data & 0x01) {
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213 if (OWReadBit())
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214 result |= 0x80;
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215 } else
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216 OWWriteBit(0);
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217
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218 data >>= 1;
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219 }
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220
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221 return(result);
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222 }
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223
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224 /*-----------------------------------------------------------------------------
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225 * Write a block of bytes to the 1-wire bus and return the sampled result in
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226 * the same buffer
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227 */
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228 void
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229 OWBlock(uint8_t *data, int len) {
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230 int i;
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231
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232 for (i = 0; i < len; i++)
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233 data[i] = OWTouchByte(data[i]);
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234 }
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235
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236
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237 /*-----------------------------------------------------------------------------
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238 * Send a 1 wire command to a device, or all if no ROM ID provided
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239 */
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240 void
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241 OWSendCmd(uint8_t *ROM, uint8_t cmd) {
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242 int i;
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243
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244 OWTouchReset();
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245
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246 if (ROM == NULL)
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247 OWWriteByte(OW_SKIP_ROM_CMD);
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248 else {
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249 OWWriteByte(OW_MATCH_ROM_CMD);
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250 for (i = 0; i < 8; i++)
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251 OWWriteByte(ROM[i]);
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252 }
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253
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254 OWWriteByte(cmd);
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255 }
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256
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257 /*-----------------------------------------------------------------------------
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258 * Search algorithm from App note 187 (and 162)
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259 *
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260 * Returns 1 when something is found, 0 if nothing present
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261 */
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262 int
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263 OWFirst(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) {
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264 /* Reset state */
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265 OW_LastDiscrepancy = 0;
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266 OW_LastDevice = 0;
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267 OW_LastFamilyDiscrepancy = 0;
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268
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269 /* Go looking */
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270 return (OWNext(ROM, do_reset, alarm_only));
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271 }
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272
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273 /* Returns 1 when something is found, 0 if nothing left */
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274 int
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275 OWNext(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) {
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276 uint8_t bit_test, search_direction, bit_number;
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277 uint8_t last_zero, rom_byte_number, next_result;
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278 uint8_t rom_byte_mask;
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279 uint8_t lastcrc8, crcaccum;
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280 char errstr[30];
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281
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282 /* Init for search */
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283 bit_number = 1;
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284 last_zero = 0;
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285 rom_byte_number = 0;
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286 rom_byte_mask = 1;
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287 next_result = 0;
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288 lastcrc8 = 0;
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289 crcaccum = 0;
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290
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291 /* if the last call was not the last one */
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292 if (!OW_LastDevice) {
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293 /* check if reset first is requested */
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294 if (do_reset) {
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295 /* reset the 1-wire
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296 * if there are no parts on 1-wire, return 0 */
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297 #if OW_DEBUG
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298 uart_putsP(PSTR("Resetting\n\r"));
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299 #endif
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300 if (OWTouchReset()) {
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301 /* reset the search */
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302 OW_LastDiscrepancy = 0;
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303 OW_LastFamilyDiscrepancy = 0;
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304 #if OW_DEBUG
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305 uart_putsP(PSTR("No devices on bus\n\r"));
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306 #endif
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307 return 0;
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308 }
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309 }
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310
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311 /* If finding alarming devices issue a different command */
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312 if (alarm_only)
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313 OWWriteByte(OW_SEARCH_ALRM_CMD); /* issue the alarming search command */
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314 else
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315 OWWriteByte(OW_SEARCH_ROM_CMD); /* issue the search command */
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316
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317 /* pause before beginning the search */
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318 OWdelay();
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319 OWdelay();
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320 OWdelay();
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321
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322 /* loop to do the search */
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323 do {
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324 /* read a bit and its compliment */
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325 bit_test = OWReadBit() << 1;
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326 bit_test |= OWReadBit();
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327
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328 #if OW_DEBUG
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329 sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test);
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330 uart_puts(errstr);
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331 #endif
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332
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333 /* check for no devices on 1-wire */
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334 if (bit_test == 3) {
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335 sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test);
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336 uart_puts(errstr);
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337 break;
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338 }
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339 else {
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340 /* all devices coupled have 0 or 1 */
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341 if (bit_test > 0)
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342 search_direction = !(bit_test & 0x01); /* bit write value for search */
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343 else {
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344 /* if this discrepancy is before the Last Discrepancy
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345 * on a previous OWNext then pick the same as last time */
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346 if (bit_number < OW_LastDiscrepancy)
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347 search_direction = ((ROM[rom_byte_number] & rom_byte_mask) > 0);
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348 else
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349 /* if equal to last pick 1, if not then pick 0 */
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350 search_direction = (bit_number == OW_LastDiscrepancy);
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351
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352 /* if 0 was picked then record its position in LastZero */
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353 if (search_direction == 0) {
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354 last_zero = bit_number;
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355
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356 /* check for Last discrepancy in family */
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357 if (last_zero < 9)
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358 OW_LastFamilyDiscrepancy = last_zero;
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359 }
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360 }
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361
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362 /* set or clear the bit in the ROM byte rom_byte_number
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363 * with mask rom_byte_mask */
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364 if (search_direction == 1)
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365 ROM[rom_byte_number] |= rom_byte_mask;
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366 else
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367 ROM[rom_byte_number] &= ~rom_byte_mask;
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368
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369 /* serial number search direction write bit */
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370 OWWriteBit(search_direction);
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371
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372 /* increment the byte counter bit_number
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373 * and shift the mask rom_byte_mask */
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374 bit_number++;
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375 rom_byte_mask <<= 1;
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376
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377 /* if the mask is 0 then go to new ROM byte rom_byte_number
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378 * and reset mask */
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379 if (rom_byte_mask == 0) {
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380 OWCRC(ROM[rom_byte_number], &crcaccum); /* accumulate the CRC */
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381 lastcrc8 = crcaccum;
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382
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383 rom_byte_number++;
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384 rom_byte_mask = 1;
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385 }
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386 }
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387 } while (rom_byte_number < 8); /* loop until through all ROM bytes 0-7 */
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388
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389 /* if the search was successful then */
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390 if (!(bit_number < 65) || lastcrc8) {
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391 if (lastcrc8) {
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392 sprintf_P(errstr, PSTR("Bad CRC (%d)\n\r"), lastcrc8);
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393 uart_puts(errstr);
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394 next_result = 0;
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395 } else {
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396 /* search successful so set LastDiscrepancy,LastDevice,next_result */
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397 OW_LastDiscrepancy = last_zero;
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398 OW_LastDevice = (OW_LastDiscrepancy == 0);
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399 #if OW_DEBUG
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400 sprintf_P(errstr, PSTR("Last device = %d\n\r"), OW_LastDevice);
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401 uart_puts(errstr);
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402 #endif
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403 next_result = 1;
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404 }
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405 }
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406 }
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407
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408 /* if no device found then reset counters so next 'next' will be
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409 * like a first */
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410 if (!next_result || !ROM[0]) {
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411 OW_LastDiscrepancy = 0;
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412 OW_LastDevice = 0;
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413 OW_LastFamilyDiscrepancy = 0;
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414 next_result = 0;
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415 }
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416
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417 return next_result;
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418
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419 }
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420
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421 uint8_t PROGMEM dscrc_table[] = {
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422 0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65,
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423 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220,
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424 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98,
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425 190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255,
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426 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7,
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427 219, 133,103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154,
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428 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36,
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429 248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185,
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430 140,210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113,147, 205,
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431 17, 79, 173, 243, 112, 46, 204, 146, 211,141, 111, 49, 178, 236, 14, 80,
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432 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82,176, 238,
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433 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115,
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434 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139,
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435 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22,
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436 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168,
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437 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53
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438 };
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439
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440 void
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441 OWCRC(uint8_t x, uint8_t *crc) {
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442 *crc = pgm_read_byte(&dscrc_table[(*crc) ^ x]);
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443 }