root / branches / autonomous_recharging / code / projects / libdragonfly / analog.c @ 322
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1 | 322 | 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 | * code mostly taken from fwr analog file (author: Tom Lauwers)
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34 | **/
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35 | |||
36 | #include <util/delay.h> |
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37 | #include <avr/interrupt.h> |
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38 | #include "analog.h" |
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39 | #include "serial.h" |
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40 | // Internal Function Prototypes
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41 | void set_adc_mux(int which); |
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42 | |||
43 | /** @brief Struct to hold the value of a particular analog port */
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44 | typedef struct { |
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45 | uint8_t adc8; |
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46 | uint16_t adc10; |
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47 | } adc_t; |
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48 | |||
49 | /**
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50 | * @defgroup analog Analog
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51 | * Functions for manipulation the ADC on the dragonfly board.
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52 | * All definitions may be found in analog.h.
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53 | *
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54 | * @{
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55 | **/
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56 | |||
57 | int adc_loop_running = 0; |
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58 | int adc_current_port = AN1;
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59 | adc_t an_val[11];
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60 | |||
61 | /**
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62 | * Initializes the ADC.
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63 | * Call analog_init before reading from the analog ports.
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64 | *
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65 | * @see analog8, analog10
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66 | **/
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67 | void analog_init(int start_conversion) |
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68 | { |
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69 | for (int i = 0; i < 11; i++) { |
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70 | an_val[i].adc10 = 0;
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71 | an_val[i].adc8 = 0;
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72 | } |
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73 | |||
74 | //cli();
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75 | // ADMUX register
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76 | // Bit 7,6 - Set voltage reference to AVcc (0b01)
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77 | // Bit 5 - ADLAR set to simplify moving from register
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78 | // Bit 4 - X
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79 | // Bit 3:0 - Sets the current channel
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80 | // Initializes to read from AN1 first (AN0 is reservered for the BOM)
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81 | ADMUX = 0;
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82 | ADMUX |= ADMUX_OPT | _BV(MUX0); |
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83 | |||
84 | |||
85 | // ADC Status Register A
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86 | // Bit 7 - ADEN is set (enables analog)
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87 | // Bit 6 - Start conversion bit is set (must be done once for free-running mode)
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88 | // Bit 5 - Enable Auto Trigger (for free running mode) NOT DOING THIS RIGHT NOW
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89 | // Bit 4 - ADC interrupt flag, 0
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90 | // Bit 3 - Enable ADC Interrupt (required to run free-running mode)
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91 | // Bits 2-0 - Set to create a clock divisor of 128, to make ADC clock = 8,000,000/64 = 125kHz
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92 | ADCSRA = 0;
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93 | ADCSRA |= _BV(ADEN) | _BV(ADIE) | _BV(ADPS2) | _BV(ADPS1) | _BV(ADPS0); |
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94 | |||
95 | // Set external mux lines to outputs
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96 | DDRG |= 0x1C;
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97 | |||
98 | // Set up first port for conversions
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99 | set_adc_mux(0x00);
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100 | adc_current_port = AN1; |
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101 | |||
102 | //Start the conversion if requested
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103 | if (start_conversion)
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104 | analog_start_loop(); |
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105 | else
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106 | analog_stop_loop(); |
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107 | //sei();
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108 | |||
109 | } |
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110 | |||
111 | unsigned int analog8(int which) { |
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112 | if (which == BOM_PORT) {
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113 | return 0; |
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114 | } else {
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115 | return an_val[which - 1].adc8; |
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116 | } |
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117 | } |
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118 | |||
119 | unsigned int analog10(int which) { |
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120 | if (which == BOM_PORT) {
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121 | return 0; |
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122 | } else {
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123 | return an_val[which - 1].adc10; |
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124 | } |
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125 | } |
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126 | |||
127 | void analog_start_loop(void) { |
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128 | //Start the conversion
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129 | ADCSRA |= _BV(ADSC); |
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130 | adc_loop_running = 0x1;
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131 | } |
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132 | |||
133 | //will stop after current conversion finishes
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134 | void analog_stop_loop(void) { |
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135 | //Stop the conversion
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136 | adc_loop_running = 0x0;
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137 | } |
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138 | /**
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139 | * Reads an eight bit number from an analog port.
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140 | * analog_init must be called before using this function.
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141 | *
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142 | * @param which the analog port to read from. One of
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143 | * the constants AN0 - AN7.
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144 | *
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145 | * @return the eight bit input to the specified port
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146 | *
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147 | * @see analog_init, analog10
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148 | **/
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149 | unsigned int analog_get8(int which) |
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150 | { |
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151 | // Let any previous conversion finish
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152 | while (ADCSRA & _BV(ADSC));
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153 | |||
154 | if(which < EXT_MUX) {
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155 | ADMUX = ADMUX_OPT + which; |
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156 | } else {
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157 | ADMUX = ADMUX_OPT + EXT_MUX; |
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158 | set_adc_mux(which - 8);
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159 | } |
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160 | |||
161 | // Start the conversion
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162 | ADCSRA |= _BV(ADSC); |
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163 | |||
164 | // Wait for the conversion to finish
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165 | while (ADCSRA & _BV(ADSC));
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166 | |||
167 | return ADCH; //since we left aligned the data, ADCH is the 8 MSB. |
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168 | } |
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169 | |||
170 | /**
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171 | * Reads a ten bit number from the specified port.
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172 | * analog_init must be called before using this function.
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173 | *
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174 | *
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175 | * @param which the analog port to read from. Typically
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176 | * a constant, one of AN0 - AN7.
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177 | *
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178 | * @return the ten bit number input to the specified port
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179 | *
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180 | * @see analog_init, analog8
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181 | **/
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182 | unsigned int analog_get10(int which) |
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183 | { |
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184 | int adc_h;
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185 | int adc_l;
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186 | |||
187 | // Let any previous conversion finish
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188 | while (ADCSRA & _BV(ADSC));
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189 | |||
190 | if(which < EXT_MUX) {
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191 | ADMUX = ADMUX_OPT + which; |
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192 | } else {
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193 | ADMUX = ADMUX_OPT + EXT_MUX; |
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194 | set_adc_mux(which - 8);
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195 | } |
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196 | |||
197 | // Start the conversion
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198 | ADCSRA |= _BV(ADSC); |
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199 | |||
200 | // Wait for the conversion to finish
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201 | while (ADCSRA & _BV(ADSC));
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202 | |||
203 | adc_l = ADCL; |
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204 | adc_h = ADCH; |
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205 | |||
206 | return ((adc_h << 2) | (adc_l >> 6)); |
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207 | } |
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208 | |||
209 | /**
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210 | * Returns the current position of the wheel, as an integer
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211 | * in the range 0 - 255.
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212 | * analog_init must be called before using this function.
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213 | *
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214 | * @return the orientation of the wheel, as an integer in
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215 | * the range 0 - 255.
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216 | *
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217 | * @see analog_init
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218 | **/
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219 | int wheel(void) |
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220 | { |
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221 | return analog_get8(WHEEL_PORT);
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222 | } |
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223 | |||
224 | |||
225 | /**
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226 | * Sets the value of the external analog mux. Values are read
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227 | * on AN7 physical port. (AN8 - AN15 are "virtual" ports).
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228 | *
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229 | * @param which which analog mux port (0-7) which corresponds
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230 | * to AN8-AN15.
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231 | *
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232 | * @bug FIX THIS IN THE NEXT BOARD REVISION:
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233 | * ADDR2 ADDR1 ADDR0
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234 | * G2.G4.G3 set mux to port 0-7 via vinary selection
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235 | * math would be much cleaner if it was G4.G3.G2
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236 | *
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237 | * @see analog_init
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238 | **/
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239 | void set_adc_mux(int which) |
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240 | { |
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241 | // mask so only proper bits are possible.
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242 | PORTG = (PORTG & 0xE3) | ((which & 0x03) << 3) | (which & 0x04); |
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243 | } |
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244 | |||
245 | /**@}**/ //end defgroup |
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246 | |||
247 | |||
248 | ISR(ADC_vect) { |
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249 | static volatile int adc_prev_loop_running = 0; |
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250 | |||
251 | int adc_h = 0; |
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252 | int adc_l = 0; |
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253 | |||
254 | //usb_putc('p');
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255 | //usb_putc('r');
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256 | //usb_puti(adc_loop_running);
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257 | //usb_puts("\n\r");
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258 | |||
259 | //Store the value only if this read isn't for the BOM
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260 | if (ADMUX != BOM_PORT) {
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261 | adc_l = ADCL; |
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262 | adc_h = ADCH; |
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263 | |||
264 | an_val[adc_current_port - 1].adc10 = (adc_h << 2) | (adc_l >> 6); |
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265 | an_val[adc_current_port - 1].adc8 = adc_h;
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266 | //usb_puti(an_val[adc_current_port - 1].adc10);
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267 | //usb_puts("\n\r");
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268 | //usb_puti(an_val[adc_current_port - 1].adc8);
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269 | //usb_puti(ADCH);
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270 | //usb_puts("\n\r");
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271 | } |
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272 | |||
273 | //Save the result only if we just turned off the loop
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274 | if (!adc_loop_running && !adc_prev_loop_running)
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275 | return;
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276 | |||
277 | adc_prev_loop_running = adc_loop_running; |
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278 | |||
279 | //Skip AN7 because it is not a real port
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280 | if (adc_current_port == AN6) {
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281 | ADMUX = ADMUX_OPT | EXT_MUX; |
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282 | set_adc_mux(AN8 - 8);
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283 | adc_current_port = AN8; |
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284 | //Wrap around
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285 | } else if (adc_current_port == AN11) { |
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286 | adc_current_port = AN1; |
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287 | ADMUX = ADMUX_OPT | adc_current_port; |
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288 | //Normal increment
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289 | } else {
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290 | adc_current_port++; |
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291 | |||
292 | if(adc_current_port < EXT_MUX) {
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293 | ADMUX = ADMUX_OPT | adc_current_port; |
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294 | } else {
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295 | ADMUX = ADMUX_OPT | EXT_MUX; |
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296 | set_adc_mux(adc_current_port - 8);
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297 | } |
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298 | } |
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299 | |||
300 | //Initiate next conversion only if we are running a loop
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301 | if (!adc_loop_running)
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302 | return;
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303 | |||
304 | ADCSRA |= _BV(ADSC); |
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305 | |||
306 | //if (ADCSRA & _BV(ADSC))
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307 | // usb_putc('s');
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308 | |||
309 | return;
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310 | } |