1 | /* |
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2 | * This file interfaces with the real-time clock found in a |
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3 | * Dallas Semiconductor DS1307/DS1308 serial real-time clock chip. |
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4 | * This RTC have I2C bus interface. BSP have to provide I2C bus primitives |
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5 | * to make this driver working. getRegister and setRegister primitives is |
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6 | * not used here to avoid multiple transactions over I2C bus (each transaction |
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7 | * require significant time and error when date/time information red may |
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8 | * occurs). ulControlPort contains I2C bus number; ulDataPort contains |
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9 | * RTC I2C device address. |
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10 | * |
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11 | * Year 2000 Note: |
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12 | * |
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13 | * This chip only uses a two digit field to store the year. This code |
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14 | * uses the RTEMS Epoch as a pivot year. This lets us map the two digit |
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15 | * year field as follows: |
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16 | * |
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17 | * + two digit years 00-87 are mapped to 2000-2087 |
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18 | * + two digit years 88-99 are mapped to 1988-1999 |
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19 | * |
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20 | * Copyright (C) 2000 OKTET Ltd., St.-Petersburg, Russia |
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21 | * Author: Victor V. Vengerov <vvv@oktet.ru> |
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22 | * |
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23 | * The license and distribution terms for this file may be |
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24 | * found in the file LICENSE in this distribution or at |
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25 | * |
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26 | * http://www.OARcorp.com/rtems/license.html. |
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27 | * |
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28 | * @(#) $Id$ |
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29 | */ |
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30 | |
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31 | #include <rtems.h> |
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32 | #include <libchip/rtc.h> |
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33 | #include <string.h> |
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34 | #include "ds1307.h" |
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35 | #include "i2c.h" |
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36 | |
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37 | /* Convert from/to Binary-Coded Decimal representation */ |
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38 | #define From_BCD( _x ) ((((_x) >> 4) * 10) + ((_x) & 0x0F)) |
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39 | #define To_BCD( _x ) ((((_x) / 10) << 4) + ((_x) % 10)) |
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40 | |
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41 | /* ds1307_initialize -- |
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42 | * Initialize DS1307 real-time clock chip. If RTC is halted, this |
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43 | * function resume counting. |
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44 | * |
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45 | * PARAMETERS: |
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46 | * minor -- minor RTC device number |
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47 | */ |
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48 | void |
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49 | ds1307_initialize(int minor) |
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50 | { |
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51 | i2c_message_status status; |
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52 | int try; |
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53 | rtems_unsigned8 sec; |
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54 | i2c_bus_number bus; |
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55 | i2c_address addr; |
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56 | |
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57 | bus = RTC_Table[minor].ulCtrlPort1; |
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58 | addr = RTC_Table[minor].ulDataPort; |
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59 | |
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60 | /* Read SECONDS register */ |
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61 | try = 0; |
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62 | do { |
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63 | status = i2c_wbrd(bus, addr, 0, &sec, sizeof(sec)); |
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64 | try++; |
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65 | } while ((status != I2C_SUCCESSFUL) && (try < 15)); |
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66 | |
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67 | /* If clock is halted, reset and start the clock */ |
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68 | if ((sec & DS1307_SECOND_HALT) != 0) |
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69 | { |
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70 | rtems_unsigned8 start[8]; |
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71 | memset(start, 0, sizeof(start)); |
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72 | start[0] = DS1307_SECOND; |
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73 | try = 0; |
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74 | do { |
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75 | status = i2c_write(bus, addr, start, 2); |
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76 | } while ((status != I2C_SUCCESSFUL) && (try < 15)); |
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77 | } |
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78 | } |
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79 | |
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80 | /* ds1307_get_time -- |
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81 | * read current time from DS1307 real-time clock chip and convert it |
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82 | * to the rtems_time_of_day structure. |
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83 | * |
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84 | * PARAMETERS: |
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85 | * minor -- minor RTC device number |
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86 | * time -- place to put return value (date and time) |
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87 | * |
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88 | * RETURNS: |
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89 | * 0, if time obtained successfully |
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90 | * -1, if error occured |
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91 | */ |
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92 | int |
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93 | ds1307_get_time(int minor, rtems_time_of_day *time) |
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94 | { |
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95 | i2c_bus_number bus; |
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96 | i2c_address addr; |
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97 | rtems_unsigned8 info[8]; |
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98 | rtems_unsigned32 v1, v2; |
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99 | i2c_message_status status; |
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100 | int try; |
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101 | |
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102 | if (time == NULL) |
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103 | return -1; |
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104 | |
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105 | bus = RTC_Table[minor].ulCtrlPort1; |
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106 | addr = RTC_Table[minor].ulDataPort; |
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107 | |
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108 | memset(time, 0, sizeof(rtems_time_of_day)); |
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109 | try = 0; |
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110 | do { |
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111 | status = i2c_wbrd(bus, addr, 0, info, sizeof(info)); |
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112 | try++; |
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113 | } while ((status != I2C_SUCCESSFUL) && (try < 10)); |
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114 | |
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115 | if (status != I2C_SUCCESSFUL) |
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116 | { |
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117 | return -1; |
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118 | } |
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119 | |
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120 | v1 = info[DS1307_YEAR]; |
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121 | v2 = From_BCD(v1); |
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122 | if (v2 < 88) |
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123 | time->year = 2000 + v2; |
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124 | else |
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125 | time->year = 1900 + v2; |
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126 | |
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127 | v1 = info[DS1307_MONTH] & ~0xE0; |
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128 | time->month = From_BCD(v1); |
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129 | |
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130 | v1 = info[DS1307_DAY] & ~0xC0; |
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131 | time->day = From_BCD(v1); |
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132 | |
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133 | v1 = info[DS1307_HOUR]; |
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134 | if (v1 & DS1307_HOUR_12) |
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135 | { |
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136 | v2 = v1 & ~0xE0; |
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137 | if (v1 & DS1307_HOUR_PM) |
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138 | { |
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139 | time->hour = From_BCD(v2) + 12; |
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140 | } |
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141 | else |
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142 | { |
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143 | time->hour = From_BCD(v2); |
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144 | } |
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145 | } |
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146 | else |
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147 | { |
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148 | v2 = v1 & ~0xC0; |
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149 | time->hour = From_BCD(v2); |
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150 | } |
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151 | |
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152 | v1 = info[DS1307_MINUTE] & ~0x80; |
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153 | time->minute = From_BCD(v1); |
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154 | |
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155 | v1 = info[DS1307_SECOND]; |
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156 | v2 = v1 & ~0x80; |
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157 | time->second = From_BCD(v2); |
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158 | |
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159 | return 0; |
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160 | } |
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161 | |
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162 | /* ds1307_set_time -- |
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163 | * set time to the DS1307 real-time clock chip |
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164 | * |
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165 | * PARAMETERS: |
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166 | * minor -- minor RTC device number |
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167 | * time -- new date and time to be written to DS1307 |
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168 | * |
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169 | * RETURNS: |
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170 | * 0, if time obtained successfully |
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171 | * -1, if error occured |
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172 | */ |
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173 | int |
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174 | ds1307_set_time(int minor, rtems_time_of_day *time) |
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175 | { |
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176 | i2c_bus_number bus; |
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177 | i2c_address addr; |
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178 | rtems_unsigned8 info[8]; |
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179 | i2c_message_status status; |
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180 | int try; |
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181 | |
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182 | if (time == NULL) |
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183 | return -1; |
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184 | |
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185 | bus = RTC_Table[minor].ulCtrlPort1; |
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186 | addr = RTC_Table[minor].ulDataPort; |
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187 | |
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188 | if (time->year >= 2088) |
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189 | rtems_fatal_error_occurred(RTEMS_INVALID_NUMBER); |
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190 | |
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191 | info[0] = DS1307_SECOND; |
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192 | info[1 + DS1307_YEAR] = To_BCD(time->year % 100); |
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193 | info[1 + DS1307_MONTH] = To_BCD(time->month); |
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194 | info[1 + DS1307_DAY] = To_BCD(time->day); |
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195 | info[1 + DS1307_HOUR] = To_BCD(time->hour); |
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196 | info[1 + DS1307_MINUTE] = To_BCD(time->minute); |
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197 | info[1 + DS1307_SECOND] = To_BCD(time->second); |
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198 | info[1 + DS1307_DAY_OF_WEEK] = 1; /* Do not set day of week */ |
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199 | |
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200 | try = 0; |
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201 | do { |
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202 | status = i2c_write(bus, addr, info, 8); |
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203 | try++; |
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204 | } while ((status != I2C_SUCCESSFUL) && (try < 10)); |
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205 | |
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206 | if (status != I2C_SUCCESSFUL) |
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207 | return -1; |
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208 | else |
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209 | return 0; |
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210 | } |
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211 | |
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212 | /* Driver function table */ |
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213 | |
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214 | rtc_fns ds1307_fns = { |
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215 | ds1307_initialize, |
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216 | ds1307_get_time, |
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217 | ds1307_set_time |
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218 | }; |
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