root / branches / encoders / code / lib / src / libdragonfly / encoders.c @ 1345
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1 | 749 | bneuman | #include "encoders.h" |
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2 | #include "spi.h" |
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3 | #include <dragonfly_lib.h> |
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4 | #include "ring_buffer.h" |
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5 | 546 | kwoo | |
6 | 749 | bneuman | unsigned int left_data_buf; |
7 | unsigned int right_data_buf; |
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8 | 844 | justin | char encoder_buf_index;
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9 | 749 | bneuman | |
10 | unsigned int left_data; |
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11 | unsigned int right_data; |
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12 | |||
13 | unsigned int left_data_array[BUFFER_SIZE]; |
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14 | unsigned int right_data_array[BUFFER_SIZE]; |
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15 | int left_data_idx;
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16 | int right_data_idx;
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17 | |||
18 | int left_dx;
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19 | int right_dx;
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20 | long int timecount; |
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21 | |||
22 | 771 | bneuman | volatile short int data_ready; |
23 | |||
24 | 749 | bneuman | void encoder_recv(char data); |
25 | |||
26 | //Helper Function Prototypes
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27 | inline void left_data_array_put(unsigned short int value); |
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28 | inline unsigned int left_data_array_top(void); |
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29 | inline unsigned int left_data_array_prev(void); |
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30 | inline unsigned int left_data_array_bottom(void); |
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31 | |||
32 | inline void right_data_array_put(unsigned short int value); |
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33 | inline unsigned int right_data_array_top(void); |
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34 | inline unsigned int right_data_array_prev(void); |
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35 | inline unsigned int right_data_array_bottom(void); |
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36 | |||
37 | |||
38 | void encoder_recv_complete(){
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39 | 1345 | chihsiuh | encoder_buf_index = 0;
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40 | data_ready++; |
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41 | 771 | bneuman | |
42 | 1345 | chihsiuh | spi_transfer(5);
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43 | 749 | bneuman | } |
44 | |||
45 | 1345 | chihsiuh | /**
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46 | * @brief Initializes encoder variables and the hardware interface.
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47 | */
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48 | 749 | bneuman | void encoders_init(void){ |
49 | int i;
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50 | 771 | bneuman | |
51 | data_ready=0;
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52 | 749 | bneuman | |
53 | 1345 | chihsiuh | spi_init(encoder_recv, encoder_recv_complete); |
54 | 844 | justin | encoder_buf_index = 0;
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55 | 749 | bneuman | left_data_buf = 0;
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56 | right_data_buf= 0;
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57 | left_data = -1;
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58 | right_data = -1;
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59 | 771 | bneuman | |
60 | 749 | bneuman | //RING_BUFFER_INIT(enc_buffer,BUFFER_SIZE);
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61 | left_data_idx = 0;
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62 | right_data_idx = 0;
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63 | for(i = 0; i < BUFFER_SIZE; i++) { |
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64 | left_data_array[i] = 0;
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65 | } |
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66 | for(i = 0; i < BUFFER_SIZE; i++) { |
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67 | right_data_array[i] = 0;
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68 | } |
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69 | spi_transfer(5);
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70 | } |
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71 | |||
72 | 809 | justin | /**
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73 | 1345 | chihsiuh | * @brief Returns the specified encoders value
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74 | 809 | justin | *
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75 | * @param encoder this is the encoder that you want to read. Valid arguments
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76 | * are LEFT and RIGHT
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77 | *
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78 | * @return the value of the specified encoder
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79 | **/
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80 | 749 | bneuman | int encoder_read(char encoder){ |
81 | 1345 | chihsiuh | |
82 | if(encoder==LEFT) return left_data; |
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83 | else if(encoder==RIGHT) return right_data; |
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84 | else return -1; |
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85 | 749 | bneuman | } |
86 | |||
87 | |||
88 | 1345 | chihsiuh | /**
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89 | * @brief Outputs encoder direction as FORWARD OR BACK
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90 | * A STUB! DO NOT use.
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91 | *
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92 | * @param encoder The encoder you want the direction of.
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93 | * Valid arguments are right and left.
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94 | *
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95 | * @return FORWARD or BACK (the constants)
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96 | */
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97 | 749 | bneuman | char encoder_direction(char encoder){ |
98 | return 0; |
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99 | } |
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100 | 1345 | chihsiuh | |
101 | 809 | justin | /**
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102 | 1345 | chihsiuh | * Gets the total distance covered by the specified encoder (in encoder clicks)
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103 | 809 | justin | *
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104 | * @param encoder the encoder that you want to read, use LEFT or RIGHT
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105 | *
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106 | 1345 | chihsiuh | * @return The distance covered by the specified encoder.
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107 | 809 | justin | **/
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108 | 749 | bneuman | int encoder_get_dx(char encoder) { |
109 | 1345 | chihsiuh | |
110 | if(encoder==LEFT) return left_dx; |
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111 | else if(encoder==RIGHT) return right_dx; |
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112 | 749 | bneuman | else return -1; |
113 | } |
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114 | |||
115 | 809 | justin | /**
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116 | 1345 | chihsiuh | * Resets the distance accumulator for the specified
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117 | 809 | justin | * encoder.
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118 | *
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119 | 1345 | chihsiuh | * @param encoder the encoder that you want to reset distance for
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120 | 809 | justin | **/
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121 | 749 | bneuman | void encoder_rst_dx(char encoder) { |
122 | 1345 | chihsiuh | |
123 | if(encoder==LEFT) left_dx = 0; |
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124 | else if(encoder==RIGHT) right_dx = 0; |
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125 | 749 | bneuman | } |
126 | |||
127 | 1345 | chihsiuh | /**
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128 | * @brief Returns the number of encoder reads that have occurred.
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129 | *
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130 | * @return The time count.
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131 | */
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132 | 749 | bneuman | int encoder_get_tc(void) { |
133 | return timecount;
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134 | } |
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135 | |||
136 | 1345 | chihsiuh | /**
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137 | * @brief Resets the encoder read counter.
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138 | */
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139 | 749 | bneuman | void encoder_rst_tc(void) { |
140 | timecount = 0;
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141 | } |
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142 | |||
143 | 1345 | chihsiuh | ///////////////////////////////////////////////////////////////////////
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144 | int left_data_at(int index) { |
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145 | int tmp_idx = left_data_idx - index;
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146 | if (tmp_idx < 0) |
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147 | tmp_idx += BUFFER_SIZE; |
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148 | return left_data_array[tmp_idx];
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149 | } |
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150 | 749 | bneuman | |
151 | 1345 | chihsiuh | int right_data_at(int index) { |
152 | int tmp_idx = right_data_idx - index;
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153 | if (tmp_idx < 0) |
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154 | tmp_idx += BUFFER_SIZE; |
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155 | return right_data_array[tmp_idx];
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156 | } |
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157 | |||
158 | |||
159 | int get_dx(char encoder, int index) { |
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160 | int dx, ctr;
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161 | ctr = 0;
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162 | dx = 1024;
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163 | do {
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164 | if (encoder == LEFT)
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165 | dx = left_data_at(index+ctr+38) - left_data_at(index+ctr);
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166 | else
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167 | dx = right_data_at(index+ctr) - right_data_at(index+ctr+38);
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168 | ctr++; |
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169 | } while ((dx > 30 || dx < -30) && ctr < 3); |
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170 | if (dx > 30 || dx < -30) |
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171 | return ERR_VEL;
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172 | return dx;
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173 | } |
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174 | /**
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175 | * @brief Returns the approximated instantaneous velocity of the robot
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176 | * in terms of encoder clicks.
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177 | *
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178 | * @param encoder RIGHT or LEFT - the wheel you want the velocity for.
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179 | *
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180 | * @return The instantaneous velocity for the given wheel.
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181 | */
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182 | 771 | bneuman | int encoder_get_v(char encoder){ |
183 | 1345 | chihsiuh | /*
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184 | if (encoder == LEFT)
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185 | return left_data_array_bottom() - left_data_array_top();
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186 | 771 | bneuman | |
187 | 1345 | chihsiuh | if (encoder == RIGHT)
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188 | return right_data_array_top() - right_data_array_bottom();
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189 | 771 | bneuman | |
190 | 1345 | chihsiuh | return -1;
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191 | */
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192 | int vel1, vel2, tmp;
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193 | vel1 = get_dx(encoder, 0);
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194 | vel2 = get_dx(encoder, 1);
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195 | |||
196 | if (vel1 == ERR_VEL && vel2 == ERR_VEL)
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197 | return ERR_VEL << 1; |
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198 | else if (vel2 == ERR_VEL) |
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199 | return vel1 << 1; |
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200 | else if (vel1 == ERR_VEL) |
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201 | return vel2 << 1; |
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202 | else
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203 | return vel1 + vel2;
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204 | 771 | bneuman | } |
205 | 1345 | chihsiuh | /////////////////////////////////////////////////////////////////////////
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206 | 771 | bneuman | |
207 | 1345 | chihsiuh | /**
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208 | * @brief Waits until n encoder reads have occurred.
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209 | * Counter is reset on functions exit.
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210 | *
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211 | * @param n
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212 | */
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213 | 771 | bneuman | void encoder_wait(int n){ |
214 | while(data_ready<n);
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215 | data_ready=0;
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216 | } |
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217 | |||
218 | |||
219 | 749 | bneuman | //Full reads occur every 40 microseconds. This function should be called
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220 | //every 8 microseconds.
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221 | void encoder_recv(char data){ |
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222 | short int dx; |
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223 | |||
224 | 809 | justin | //Parse the encoder data, comes in over 5 bytes 16 bits per encoder,
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225 | // second is offset by 1 bit.
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226 | 844 | justin | switch(encoder_buf_index){
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227 | 809 | justin | case 0: |
228 | right_data_buf |= ((short)data)<<8 & 0xff00; |
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229 | break;
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230 | case 1: |
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231 | right_data_buf |= ((short)data) & 0xff; |
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232 | break;
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233 | case 2: |
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234 | left_data_buf |= (((short)data) << 9) & (0x7F << 9); |
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235 | break;
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236 | case 3: |
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237 | left_data_buf |= (((short)data) << 1) & (0xFF<<1); |
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238 | break;
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239 | case 4: left_data_buf |= (((short)data)>>7) & 0x1; |
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240 | } |
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241 | 771 | bneuman | |
242 | 844 | justin | encoder_buf_index = (encoder_buf_index + 1) % 5; |
243 | 752 | bneuman | |
244 | 844 | justin | if(encoder_buf_index==0) { |
245 | 1345 | chihsiuh | |
246 | /*Error handling for the left encoder*/
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247 | if(!(left_data_buf & OCF))
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248 | left_data = ENCODER_DATA_NOT_READY; |
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249 | if(left_data_buf & (COF | LIN))
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250 | left_data = ENCODER_MISALIGNED; |
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251 | else if((left_data_buf & MagINCn) && (left_data_buf & MagDECn)) |
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252 | left_data = ENCODER_MAGNET_FAILURE; |
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253 | 809 | justin | else left_data = (left_data_buf>>5) & 1023; |
254 | 771 | bneuman | |
255 | 1345 | chihsiuh | /*Error handling for the right encoder*/
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256 | if(!(right_data_buf & OCF))
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257 | right_data = ENCODER_DATA_NOT_READY; |
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258 | if(right_data_buf & (COF | LIN))
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259 | right_data = ENCODER_MISALIGNED; |
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260 | else if ((right_data_buf & MagINCn) && (right_data_buf & MagDECn)) |
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261 | right_data = ENCODER_MAGNET_FAILURE; |
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262 | 809 | justin | else right_data = (right_data_buf>>5) & 1023; |
263 | 771 | bneuman | |
264 | 809 | justin | left_data_buf = 0;
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265 | right_data_buf = 0;
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266 | 749 | bneuman | |
267 | 1345 | chihsiuh | /*Above 1023 is invalid data*/
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268 | if(!(left_data > 1023)) { |
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269 | 771 | bneuman | left_data_array_put(left_data); |
270 | 752 | bneuman | |
271 | 771 | bneuman | //Adjust left accumulator
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272 | 1345 | chihsiuh | dx = - left_data + left_data_array_prev(); |
273 | 771 | bneuman | |
274 | 809 | justin | if(left_data_array_prev()==0) dx=0; |
275 | 752 | bneuman | |
276 | 809 | justin | if(dx > 512) left_dx += dx - 1023; //Underflow |
277 | else if(dx < -512) left_dx += dx + 1023; //Overflow |
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278 | else left_dx += dx;
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279 | 749 | bneuman | } |
280 | |||
281 | 1345 | chihsiuh | /*Above 1023 is invalid data*/
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282 | if(!(right_data > 1023)) { |
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283 | 771 | bneuman | right_data_array_put(right_data); |
284 | 749 | bneuman | |
285 | 771 | bneuman | //Adjust right accumulator
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286 | dx = right_data - right_data_array_prev(); |
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287 | 752 | bneuman | |
288 | 809 | justin | if(right_data_array_prev()==0) dx=0; |
289 | |||
290 | if(dx > 512) right_dx += dx - 1023; //underflow |
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291 | else if(dx < -512) right_dx += dx + 1023; //overflow |
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292 | else right_dx += dx;
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293 | 749 | bneuman | } |
294 | 809 | justin | } |
295 | 749 | bneuman | |
296 | 809 | justin | //Increment timecount accumulator
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297 | timecount++; |
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298 | 749 | bneuman | } |
299 | |||
300 | 844 | justin | |
301 | 749 | bneuman | //Helper Functions
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302 | inline void left_data_array_put(unsigned short int value) { |
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303 | if(left_data_idx == BUFFER_SIZE-1) |
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304 | left_data_idx = 0;
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305 | else
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306 | left_data_idx++; |
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307 | left_data_array[left_data_idx] = value; |
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308 | } |
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309 | |||
310 | inline unsigned int left_data_array_top(void) { |
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311 | return left_data_array[left_data_idx];
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312 | } |
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313 | |||
314 | inline unsigned int left_data_array_prev(void) { |
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315 | if(left_data_idx == 0) |
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316 | return left_data_array[BUFFER_SIZE-1]; |
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317 | else
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318 | return left_data_array[left_data_idx - 1]; |
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319 | } |
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320 | |||
321 | inline unsigned int left_data_array_bottom(void) { |
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322 | if(left_data_idx == BUFFER_SIZE-1) |
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323 | return left_data_array[0]; |
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324 | else
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325 | return left_data_array[left_data_idx + 1]; |
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326 | } |
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327 | |||
328 | inline void right_data_array_put(unsigned short int value) { |
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329 | if(right_data_idx == BUFFER_SIZE-1) |
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330 | right_data_idx = 0;
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331 | else
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332 | right_data_idx++; |
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333 | right_data_array[right_data_idx] = value; |
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334 | } |
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335 | |||
336 | inline unsigned int right_data_array_top(void) { |
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337 | return right_data_array[right_data_idx];
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338 | } |
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339 | |||
340 | inline unsigned int right_data_array_prev(void) { |
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341 | if(right_data_idx == 0) |
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342 | return right_data_array[BUFFER_SIZE-1]; |
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343 | else
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344 | return right_data_array[right_data_idx - 1]; |
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345 | } |
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346 | |||
347 | inline unsigned int right_data_array_bottom(void) { |
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348 | if(right_data_idx == BUFFER_SIZE-1) |
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349 | return right_data_array[0]; |
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350 | else
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351 | return right_data_array[right_data_idx + 1]; |
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352 | } |