root / trunk / code / projects / libdragonfly / encoders.c @ 890
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1 | 868 | justin | #include "encoders.h" |
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2 | #include "spi.h" |
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3 | 890 | justin | #include "dragonfly_lib.h" |
4 | 868 | justin | #include "ring_buffer.h" |
5 | |||
6 | unsigned int left_data_buf; |
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7 | unsigned int right_data_buf; |
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8 | char encoder_buf_index;
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9 | |||
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 | int left_v;
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23 | int right_v;
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24 | |||
25 | |||
26 | volatile short int data_ready; |
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27 | |||
28 | void encoder_recv(char data); |
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29 | |||
30 | //Helper Function Prototypes
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31 | inline void left_data_array_put(unsigned short int value); |
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32 | inline unsigned int left_data_array_top(void); |
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33 | inline unsigned int left_data_array_prev(void); |
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34 | inline unsigned int left_data_array_bottom(void); |
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35 | |||
36 | inline void right_data_array_put(unsigned short int value); |
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37 | inline unsigned int right_data_array_top(void); |
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38 | inline unsigned int right_data_array_prev(void); |
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39 | inline unsigned int right_data_array_bottom(void); |
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40 | |||
41 | |||
42 | 890 | justin | void encoder_recv_complete(void){ |
43 | 868 | justin | encoder_buf_index = 0;
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44 | data_ready++; |
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45 | |||
46 | spi_transfer(5);
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47 | } |
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48 | |||
49 | /**
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50 | * @brief Initializes encoder variables and the hardware interface.
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51 | */
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52 | void encoders_init(void){ |
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53 | int i;
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54 | |||
55 | data_ready=0;
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56 | |||
57 | spi_init(encoder_recv, encoder_recv_complete); |
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58 | encoder_buf_index = 0;
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59 | left_data_buf = 0;
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60 | right_data_buf= 0;
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61 | left_data = -1;
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62 | right_data = -1;
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63 | |||
64 | |||
65 | left_v=0;
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66 | right_v=0;
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67 | |||
68 | //RING_BUFFER_INIT(enc_buffer,BUFFER_SIZE);
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69 | left_data_idx = 0;
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70 | right_data_idx = 0;
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71 | for(i = 0; i < BUFFER_SIZE; i++) { |
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72 | left_data_array[i] = 0;
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73 | } |
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74 | for(i = 0; i < BUFFER_SIZE; i++) { |
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75 | right_data_array[i] = 0;
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76 | } |
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77 | spi_transfer(5);
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78 | } |
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79 | |||
80 | /**
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81 | * @brief Returns the specified encoders value
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82 | *
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83 | * @param encoder this is the encoder that you want to read. Valid arguments
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84 | * are LEFT and RIGHT
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85 | *
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86 | * @return the value of the specified encoder
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87 | **/
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88 | int encoder_read(char encoder){ |
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89 | |||
90 | if(encoder==LEFT) return left_data; |
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91 | else if(encoder==RIGHT) return right_data; |
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92 | else return -1; |
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93 | } |
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94 | |||
95 | /**
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96 | * Gets the total distance covered by the specified encoder (in encoder clicks)
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97 | *
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98 | * @param encoder the encoder that you want to read, use LEFT or RIGHT
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99 | *
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100 | * @return The distance covered by the specified encoder.
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101 | **/
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102 | int encoder_get_dx(char encoder) { |
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103 | |||
104 | if(encoder==LEFT) return left_dx; |
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105 | else if(encoder==RIGHT) return right_dx; |
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106 | else return -1; |
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107 | } |
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108 | |||
109 | /**
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110 | * Resets the distance accumulator for the specified
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111 | * encoder.
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112 | *
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113 | * @param encoder the encoder that you want to reset distance for
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114 | **/
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115 | void encoder_rst_dx(char encoder) { |
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116 | |||
117 | if(encoder==LEFT) left_dx = 0; |
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118 | else if(encoder==RIGHT) right_dx = 0; |
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119 | } |
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120 | |||
121 | /**
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122 | * @brief Returns the number of encoder reads that have occurred.
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123 | *
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124 | * @return The time count.
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125 | */
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126 | int encoder_get_tc(void) { |
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127 | return timecount;
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128 | } |
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129 | |||
130 | /**
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131 | * @brief Resets the encoder read counter.
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132 | */
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133 | void encoder_rst_tc(void) { |
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134 | timecount = 0;
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135 | } |
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136 | |||
137 | /**
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138 | * @brief Waits until n encoder reads have occurred.
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139 | * Counter is reset on functions exit.
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140 | *
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141 | * @param n
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142 | */
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143 | void encoder_wait(int n){ |
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144 | while(data_ready<n);
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145 | data_ready=0;
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146 | } |
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147 | |||
148 | |||
149 | //Full reads occur every 40 microseconds. This function should be called
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150 | //every 8 microseconds.
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151 | void encoder_recv(char data){ |
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152 | short int dx; |
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153 | |||
154 | //Parse the encoder data, comes in over 5 bytes 16 bits per encoder,
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155 | // second is offset by 1 bit.
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156 | switch(encoder_buf_index){
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157 | case 0: |
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158 | right_data_buf |= ((short)data)<<8 & 0xff00; |
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159 | break;
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160 | case 1: |
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161 | right_data_buf |= ((short)data) & 0xff; |
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162 | break;
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163 | case 2: |
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164 | left_data_buf |= (((short)data) << 9) & (0x7F << 9); |
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165 | break;
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166 | case 3: |
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167 | left_data_buf |= (((short)data) << 1) & (0xFF<<1); |
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168 | break;
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169 | case 4: left_data_buf |= (((short)data)>>7) & 0x1; |
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170 | } |
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171 | |||
172 | encoder_buf_index = (encoder_buf_index + 1) % 5; |
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173 | |||
174 | if(encoder_buf_index==0) { |
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175 | |||
176 | /*Error handling for the left encoder*/
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177 | if(!(left_data_buf & OCF))
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178 | left_data = ENCODER_DATA_NOT_READY; |
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179 | if(left_data_buf & (COF | LIN))
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180 | left_data = ENCODER_MISALIGNED; |
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181 | else if((left_data_buf & MagINCn) && (left_data_buf & MagDECn)) |
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182 | left_data = ENCODER_MAGNET_FAILURE; |
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183 | else left_data = (left_data_buf>>5) & 1023; |
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184 | |||
185 | /*Error handling for the right encoder*/
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186 | if(!(right_data_buf & OCF))
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187 | right_data = ENCODER_DATA_NOT_READY; |
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188 | if(right_data_buf & (COF | LIN))
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189 | right_data = ENCODER_MISALIGNED; |
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190 | else if ((right_data_buf & MagINCn) && (right_data_buf & MagDECn)) |
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191 | right_data = ENCODER_MAGNET_FAILURE; |
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192 | else right_data = (right_data_buf>>5) & 1023; |
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193 | |||
194 | left_data_buf = 0;
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195 | right_data_buf = 0;
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196 | |||
197 | /*Note: Above 1023 is invalid data*/
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198 | if(!(left_data > 1023)) { |
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199 | 870 | justin | //Reverse the left wheel since encoders are necessarily mounted backwards.
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200 | left_data = 1023 - left_data;
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201 | 868 | justin | left_data_array_put(left_data); |
202 | |||
203 | //Adjust left accumulator
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204 | dx = left_data - left_data_array_prev(); |
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205 | |||
206 | //Adjust velocity: save last dx
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207 | left_v = left_dx; |
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208 | |||
209 | if(left_data_array_prev()==0) dx=0; |
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210 | |||
211 | if(dx > 512) left_dx += dx - 1023; //Underflow |
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212 | else if(dx < -512) left_dx += dx + 1023; //Overflow |
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213 | else left_dx += dx;
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214 | |||
215 | //Adjust velocity: update
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216 | left_v = left_dx - left_v; |
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217 | } |
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218 | |||
219 | /*Above 1023 is invalid data*/
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220 | if(!(right_data > 1023)) { |
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221 | right_data_array_put(right_data); |
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222 | |||
223 | //Adjust right accumulator
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224 | dx = right_data - right_data_array_prev(); |
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225 | |||
226 | if(right_data_array_prev()==0) dx=0; |
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227 | |||
228 | if(dx > 512) right_dx += dx - 1023; //underflow |
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229 | else if(dx < -512) right_dx += dx + 1023; //overflow |
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230 | else right_dx += dx;
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231 | } |
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232 | } |
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233 | |||
234 | //Increment timecount accumulator
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235 | timecount++; |
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236 | } |
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237 | |||
238 | |||
239 | //Helper Functions
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240 | inline void left_data_array_put(unsigned short int value) { |
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241 | if(left_data_idx == BUFFER_SIZE-1) |
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242 | left_data_idx = 0;
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243 | else
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244 | left_data_idx++; |
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245 | left_data_array[left_data_idx] = value; |
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246 | } |
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247 | |||
248 | inline unsigned int left_data_array_top(void) { |
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249 | return left_data_array[left_data_idx];
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250 | } |
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251 | |||
252 | inline unsigned int left_data_array_prev(void) { |
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253 | if(left_data_idx == 0) |
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254 | return left_data_array[BUFFER_SIZE-1]; |
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255 | else
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256 | return left_data_array[left_data_idx - 1]; |
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257 | } |
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258 | |||
259 | inline unsigned int left_data_array_bottom(void) { |
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260 | if(left_data_idx == BUFFER_SIZE-1) |
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261 | return left_data_array[0]; |
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262 | else
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263 | return left_data_array[left_data_idx + 1]; |
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264 | } |
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265 | |||
266 | inline void right_data_array_put(unsigned short int value) { |
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267 | if(right_data_idx == BUFFER_SIZE-1) |
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268 | right_data_idx = 0;
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269 | else
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270 | right_data_idx++; |
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271 | right_data_array[right_data_idx] = value; |
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272 | } |
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273 | |||
274 | inline unsigned int right_data_array_top(void) { |
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275 | return right_data_array[right_data_idx];
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276 | } |
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277 | |||
278 | inline unsigned int right_data_array_prev(void) { |
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279 | if(right_data_idx == 0) |
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280 | return right_data_array[BUFFER_SIZE-1]; |
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281 | else
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282 | return right_data_array[right_data_idx - 1]; |
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283 | } |
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284 | |||
285 | inline unsigned int right_data_array_bottom(void) { |
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286 | if(right_data_idx == BUFFER_SIZE-1) |
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287 | return right_data_array[0]; |
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288 | else
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289 | return right_data_array[right_data_idx + 1]; |
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290 | } |