root / trunk / code / projects / libdragonfly / analog.c @ 1925
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1 | 338 | bcoltin | /**
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2 | * Copyright (c) 2007 Colony Project
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3 | *
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4 | * Permission is hereby granted, free of charge, to any person
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5 | * obtaining a copy of this software and associated documentation
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6 | * files (the "Software"), to deal in the Software without
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7 | * restriction, including without limitation the rights to use,
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8 | * copy, modify, merge, publish, distribute, sublicense, and/or sell
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9 | * copies of the Software, and to permit persons to whom the
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10 | * Software is furnished to do so, subject to the following
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11 | * conditions:
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12 | *
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13 | * The above copyright notice and this permission notice shall be
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14 | * included in all copies or substantial portions of the Software.
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15 | *
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16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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17 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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18 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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19 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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20 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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21 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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22 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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23 | * OTHER DEALINGS IN THE SOFTWARE.
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24 | **/
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25 | |||
26 | /**
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27 | * @file analog.c
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28 | * @brief Analog input and output
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29 | *
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30 | * Contains functions for manipulating the ADC on the Dragonfly board.
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31 | *
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32 | * @author Colony Project, CMU Robotics Club
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33 | 1406 | jykong | * originally taken from fwr analog file (author: Tom Lauwers)
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34 | * loop code written by Kevin Woo and James Kong
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35 | 338 | bcoltin | **/
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36 | |||
37 | #include <util/delay.h> |
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38 | #include <avr/interrupt.h> |
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39 | 1496 | jsexton | #include "analog.h" |
40 | 1462 | dsschult | #include "serial.h" |
41 | 338 | bcoltin | // Internal Function Prototypes
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42 | void set_adc_mux(int which); |
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43 | |||
44 | /**
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45 | * @defgroup analog Analog
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46 | * Functions for manipulation the ADC on the dragonfly board.
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47 | * All definitions may be found in analog.h.
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48 | *
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49 | * @{
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50 | **/
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51 | |||
52 | 1406 | jykong | volatile int adc_loop_status = ADC_LOOP_STOPPED; |
53 | volatile int adc_sig_stop_loop = 0; |
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54 | volatile int adc_current_port = 0; |
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55 | volatile adc_t an_val[11]; |
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56 | 338 | bcoltin | |
57 | /**
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58 | * Initializes the ADC.
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59 | * Call analog_init before reading from the analog ports.
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60 | *
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61 | 437 | kwoo | * @see analog8, analog10, analog_get8, analog_get10
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62 | 1406 | jykong | *
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63 | * @bug First conversion takes a performance penalty of
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64 | * 25 vs. 13 ADC clock cycles of successive conversions.
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65 | * Analog_init should run a dummy conversion to pre-empt
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66 | * this.
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67 | *
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68 | * For good 10-bit precision, ACD clock must be between
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69 | * 50kHz and 200kHz. Currently, ADC clock is fixed at
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70 | * 125kHz using 1/64prescalar. However, most code uses
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71 | * 8-bit precision which can work at ADC clock speeds
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72 | * higher than 200kHz. Experimental tests needed to
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73 | * determine highest clock speed for accurate 8-bit ADC.
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74 | *
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75 | 338 | bcoltin | **/
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76 | 1496 | jsexton | void analog_init(int start_conversion) { |
77 | 1924 | azirbel | start_conversion=0; //forces the analog loop off |
78 | for (int i = 0; i < 11; i++) { |
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79 | an_val[i].adc10 = 0;
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80 | an_val[i].adc8 = 0;
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81 | } |
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82 | 338 | bcoltin | |
83 | 1924 | azirbel | // ADMUX register
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84 | // Bit 7,6 - Set voltage reference to AVcc (0b01)
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85 | // Bit 5 - ADLAR set to simplify moving from register
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86 | // Bit 4 - X
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87 | // Bit 3:0 - Sets the current channel
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88 | // Initializes to read from AN1 first (AN0 is reservered for the BOM)
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89 | ADMUX = 0;
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90 | ADMUX |= ADMUX_OPT | _BV(MUX0); |
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91 | 338 | bcoltin | |
92 | 1924 | azirbel | // ADC Status Register A
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93 | // Bit 7 - ADEN is set (enables analog)
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94 | // Bit 6 - Start conversion bit is set (must be done once for free-running mode)
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95 | // Bit 5 - Enable Auto Trigger (for free running mode) NOT DOING THIS RIGHT NOW
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96 | // Bit 4 - ADC interrupt flag, 0
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97 | // Bit 3 - Enable ADC Interrupt (required to run free-running mode)
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98 | // Bits 2-0 - Set to create a clock divisor of 2, to make ADC clock != 8,000,000/64 = 125kHz (it runs at highest frequency)
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99 | ADCSRA = 0;
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100 | ADCSRA |= _BV(ADEN) | /*_BV(ADPS2) | _BV(ADPS1) |*/ _BV(ADPS0);
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101 | 1922 | azirbel | |
102 | 1924 | azirbel | // Set external mux lines to outputs
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103 | DDRG |= 0x1C;
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104 | 1922 | azirbel | |
105 | 1924 | azirbel | // Set line sensor mux lines to output. Uses LCD/SPI header
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106 | DDRD |=0xE0;
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107 | 338 | bcoltin | |
108 | 1924 | azirbel | // Set up first port for conversions
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109 | set_adc_mux(0x00);
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110 | adc_current_port = AN1; |
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111 | |||
112 | //Start the conversion loop if requested
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113 | if (start_conversion)
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114 | analog_start_loop(); |
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115 | |||
116 | //Conversion loop disabled by default
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117 | 338 | bcoltin | } |
118 | |||
119 | 862 | kwoo | /**
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120 | * Returns the 8-bit analog conversion of which from
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121 | * the lookup table. If the requested port is the BOM_PORT
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122 | * you will get an automatic 0 since the BOM_PORT is not
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123 | * read in the loop and not stored. If you need that port
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124 | * you should use the functions in bom.c. There is an analog_get8
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125 | * function which for instant lookups but should be avoided unless
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126 | * you know what you're doing.
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127 | *
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128 | * @param which the port that you want to read
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129 | *
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130 | * @bug may cause a seg fault if which is a larger value
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131 | * than exists in an_val table. Not sure if we should fix
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132 | * this or not since it would add overhead.
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133 | *
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134 | * @return 8-bit analog value for the which port requested
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135 | *
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136 | * @see analog10, analog_get8, analog_get10
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137 | **/
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138 | 338 | bcoltin | unsigned int analog8(int which) { |
139 | 1924 | azirbel | /* if (which == BOM_PORT) {
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140 | return 0;
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141 | } else {
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142 | return an_val[which - 1].adc8;
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143 | }
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144 | */
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145 | return analog_get8(which);
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146 | 338 | bcoltin | } |
147 | |||
148 | 437 | kwoo | /**
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149 | * Returns the 10-bit analog conversion of which from
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150 | * the lookup table. If the requested port is the BOM_PORT
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151 | * you will get an automatic 0 since the BOM_PORT is not
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152 | * read in the loop and not stored. If you need that port
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153 | * you should use the functions in bom.c. There is an analog_get10
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154 | 862 | kwoo | * function which for instant lookups but should be avoided unless
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155 | * you know what you are doing.
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156 | 437 | kwoo | *
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157 | * @param which the port that you want to read
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158 | *
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159 | * @bug may cause a seg fault if which is a larger value
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160 | * than exists in an_val table. Not sure if we should fix
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161 | * this or not since it would add overhead.
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162 | *
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163 | * @return 10-bit analog value for the which port requested
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164 | *
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165 | * @see analog8, analog_get8, analog_get10
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166 | **/
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167 | 338 | bcoltin | unsigned int analog10(int which) { |
168 | 1924 | azirbel | /* if (which == BOM_PORT) {
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169 | return 0;
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170 | } else {
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171 | return an_val[which - 1].adc10;
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172 | }
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173 | */
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174 | return analog_get10(which);
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175 | 338 | bcoltin | } |
176 | |||
177 | 437 | kwoo | /**
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178 | * Starts the analog update loop. Will continue to run
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179 | * until analog_stop_loop is called.
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180 | *
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181 | 1406 | jykong | * @see analog_stop_loop, analog_loop_status
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182 | 437 | kwoo | **/
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183 | 1496 | jsexton | void analog_start_loop(void) { |
184 | 1924 | azirbel | if(adc_loop_status != ADC_LOOP_RUNNING){
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185 | //Start the conversion, enable ADC interrupt
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186 | ADCSRA |= _BV(ADIE); |
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187 | ADCSRA |= _BV(ADSC); |
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188 | adc_loop_status = ADC_LOOP_RUNNING; |
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189 | } |
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190 | 338 | bcoltin | } |
191 | |||
192 | 437 | kwoo | /**
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193 | * Stops the analog update loop. If there is a current
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194 | * read, it will finish up and be stored before the loop
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195 | * is interrupted. No further updates will be made until
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196 | * the loop is started again.
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197 | *
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198 | 1406 | jykong | * @see analog_start_loop, analog_loop_status
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199 | 437 | kwoo | **/
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200 | 1496 | jsexton | void analog_stop_loop() {
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201 | 1924 | azirbel | //Signal to stop after the next conversion
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202 | adc_sig_stop_loop = 1;
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203 | 338 | bcoltin | } |
204 | 1406 | jykong | |
205 | 338 | bcoltin | /**
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206 | 1406 | jykong | * Returns the status of loop. 0 for stopped.
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207 | * 1 for running. 2 for paused.
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208 | *
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209 | * @see analog_start_loop, analog_stop_loop
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210 | **/
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211 | int analog_loop_status(void) { |
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212 | 1924 | azirbel | return adc_loop_status;
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213 | 1406 | jykong | } |
214 | |||
215 | /**
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216 | 862 | kwoo | * Reads an 8-bit number from an analog port.
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217 | 338 | bcoltin | * analog_init must be called before using this function.
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218 | 862 | kwoo | * The analog loop must also be stopped before using this
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219 | * function or you will mess up the lookup table. You
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220 | * must also reenabled the loop when you are done unless
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221 | * you are doing more instant reads. See analog_stop_loop
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222 | * and analog_start_loop for more information about the loop.
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223 | 338 | bcoltin | *
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224 | * @param which the analog port to read from. One of
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225 | * the constants AN0 - AN7.
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226 | *
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227 | 862 | kwoo | * @return the 8-bit input to the specified port
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228 | 338 | bcoltin | *
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229 | 862 | kwoo | * @see analog_init, analog_get10, analog8, analog_stop_loop,
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230 | * analog_start_loop
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231 | 338 | bcoltin | **/
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232 | 439 | kwoo | unsigned int analog_get8(int which) { |
233 | 1924 | azirbel | // Let any previous conversion finish
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234 | while (ADCSRA & _BV(ADSC));
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235 | 338 | bcoltin | |
236 | 1924 | azirbel | if(which < EXT_MUX) {
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237 | ADMUX = ADMUX_OPT + which; |
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238 | } else {
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239 | ADMUX = ADMUX_OPT + EXT_MUX; |
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240 | set_adc_mux(which - 8);
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241 | } |
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242 | 338 | bcoltin | |
243 | 1924 | azirbel | // Start the conversion
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244 | ADCSRA |= _BV(ADSC); |
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245 | |||
246 | // Wait for the conversion to finish
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247 | while (ADCSRA & _BV(ADSC));
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248 | |||
249 | return ADCH; //since we left aligned the data, ADCH is the 8 MSB. |
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250 | 338 | bcoltin | } |
251 | |||
252 | /**
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253 | 862 | kwoo | * Reads an 10-bit number from an analog port.
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254 | 338 | bcoltin | * analog_init must be called before using this function.
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255 | 862 | kwoo | * The analog loop must also be stopped before using this
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256 | * function or you will mess up the lookup table. You
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257 | * must also reenabled the loop when you are done unless
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258 | * you are doing more instant reads. See analog_stop_loop
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259 | * and analog_start_loop for more information about the loop.
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260 | 338 | bcoltin | *
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261 | *
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262 | * @param which the analog port to read from. Typically
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263 | * a constant, one of AN0 - AN7.
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264 | *
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265 | 862 | kwoo | * @return the 10-bit number input to the specified port
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266 | 338 | bcoltin | *
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267 | 862 | kwoo | * @see analog_init, analog_get8, analog10, analog_stop_loop,
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268 | * analog_start_loop
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269 | 338 | bcoltin | **/
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270 | 439 | kwoo | unsigned int analog_get10(int which) { |
271 | 1924 | azirbel | int adc_h;
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272 | int adc_l;
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273 | 338 | bcoltin | |
274 | 1924 | azirbel | // Let any previous conversion finish
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275 | while (ADCSRA & _BV(ADSC));
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276 | 338 | bcoltin | |
277 | 1924 | azirbel | if(which < EXT_MUX) {
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278 | ADMUX = ADMUX_OPT + which; |
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279 | } else {
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280 | ADMUX = ADMUX_OPT + EXT_MUX; |
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281 | set_adc_mux(which - 8);
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282 | } |
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283 | 338 | bcoltin | |
284 | 1924 | azirbel | // Start the conversion
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285 | ADCSRA |= _BV(ADSC); |
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286 | |||
287 | // Wait for the conversion to finish
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288 | while (ADCSRA & _BV(ADSC));
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289 | |||
290 | adc_l = ADCL; |
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291 | adc_h = ADCH; |
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292 | |||
293 | return ((adc_h << 2) | (adc_l >> 6)); |
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294 | 338 | bcoltin | } |
295 | |||
296 | 1922 | azirbel | |
297 | /** Returns the 10 bit value from the line sensors **/
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298 | unsigned int read_line(int which) { |
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299 | 1924 | azirbel | int adc_h;
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300 | int adc_l;
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301 | 1922 | azirbel | |
302 | 1924 | azirbel | // Let any previous conversion finish
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303 | while (ADCSRA & _BV(ADSC));
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304 | 1922 | azirbel | |
305 | 1924 | azirbel | ADMUX = ADMUX_OPT + AN1; |
306 | 1922 | azirbel | |
307 | 1924 | azirbel | which = ((which&1)<<2) + ((which&2)) + ((which&4)>>2); |
308 | 1922 | azirbel | |
309 | 1924 | azirbel | // mask so only proper bits are possible.
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310 | PORTD = (PORTD & 0x1F) | ((which & 0x07) << 5); |
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311 | 1922 | azirbel | |
312 | 1925 | djacobs | //For loop is used only as a delay to allow mux to settle
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313 | for(volatile int i=0; i<5; i++); |
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314 | |||
315 | 1924 | azirbel | // Start the conversion
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316 | ADCSRA |= _BV(ADSC); |
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317 | |||
318 | // Wait for the conversion to finish
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319 | while (ADCSRA & _BV(ADSC));
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320 | |||
321 | adc_l = ADCL; |
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322 | adc_h = ADCH; |
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323 | |||
324 | return ((adc_h << 2) | (adc_l >> 6)); |
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325 | |||
326 | 1922 | azirbel | } |
327 | |||
328 | |||
329 | |||
330 | |||
331 | 338 | bcoltin | /**
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332 | * Returns the current position of the wheel, as an integer
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333 | * in the range 0 - 255.
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334 | * analog_init must be called before using this function.
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335 | *
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336 | * @return the orientation of the wheel, as an integer in
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337 | * the range 0 - 255.
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338 | *
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339 | * @see analog_init
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340 | **/
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341 | 439 | kwoo | int wheel(void) { |
342 | 1924 | azirbel | return analog8(WHEEL_PORT);
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343 | 338 | bcoltin | } |
344 | |||
345 | |||
346 | /**
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347 | * Sets the value of the external analog mux. Values are read
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348 | * on AN7 physical port. (AN8 - AN15 are "virtual" ports).
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349 | *
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350 | * @param which which analog mux port (0-7) which corresponds
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351 | * to AN8-AN15.
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352 | *
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353 | * @bug FIX THIS IN THE NEXT BOARD REVISION:
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354 | * ADDR2 ADDR1 ADDR0
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355 | * G2.G4.G3 set mux to port 0-7 via vinary selection
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356 | * math would be much cleaner if it was G4.G3.G2
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357 | *
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358 | * @see analog_init
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359 | **/
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360 | 439 | kwoo | void set_adc_mux(int which) { |
361 | 1924 | azirbel | // mask so only proper bits are possible.
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362 | PORTG = (PORTG & 0xE3) | ((which & 0x03) << 3) | (which & 0x04); |
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363 | 338 | bcoltin | } |
364 | |||
365 | /**@}**/ //end defgroup |
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366 | 1922 | azirbel | |
367 | |||
368 | ISR(ADC_vect) { |
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369 | 1924 | azirbel | int adc_h = 0; |
370 | int adc_l = 0; |
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371 | 1922 | azirbel | |
372 | 1924 | azirbel | if(adc_loop_status != ADC_LOOP_RUNNING) return; |
373 | 1922 | azirbel | |
374 | 1924 | azirbel | //Store the value only if this read isn't for the BOM
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375 | if (ADMUX != BOM_PORT) {
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376 | adc_l = ADCL; |
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377 | adc_h = ADCH; |
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378 | |||
379 | an_val[adc_current_port - 1].adc10 = (adc_h << 2) | (adc_l >> 6); |
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380 | an_val[adc_current_port - 1].adc8 = adc_h;
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381 | } |
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382 | |||
383 | //Skip AN7 because it is not a real port
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384 | if (adc_current_port == AN6) {
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385 | ADMUX = ADMUX_OPT | EXT_MUX; |
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386 | set_adc_mux(AN8 - 8);
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387 | adc_current_port = AN8; |
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388 | //Wrap around
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389 | } else if (adc_current_port == AN11) { |
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390 | adc_current_port = AN1; |
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391 | ADMUX = ADMUX_OPT | adc_current_port; |
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392 | //Normal increment
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393 | } else {
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394 | adc_current_port++; |
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395 | |||
396 | if(adc_current_port < EXT_MUX) {
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397 | ADMUX = ADMUX_OPT | adc_current_port; |
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398 | } else {
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399 | ADMUX = ADMUX_OPT | EXT_MUX; |
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400 | set_adc_mux(adc_current_port - 8);
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401 | } |
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402 | } |
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403 | |||
404 | //Stop loop if signal is set
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405 | if(adc_sig_stop_loop) {
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406 | adc_sig_stop_loop = 0;
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407 | adc_loop_status = ADC_LOOP_STOPPED; |
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408 | return;
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409 | } |
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410 | |||
411 | //Start next conversion
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412 | ADCSRA |= _BV(ADSC); |
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413 | 1922 | azirbel | } |