root / arduino-1.0 / libraries / Stepper / Stepper.cpp @ 58d82c77
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1 | 58d82c77 | Tom Mullins | /*
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2 | Stepper.cpp - - Stepper library for Wiring/Arduino - Version 0.4
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3 |
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4 | Original library (0.1) by Tom Igoe.
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5 | Two-wire modifications (0.2) by Sebastian Gassner
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6 | Combination version (0.3) by Tom Igoe and David Mellis
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7 | Bug fix for four-wire (0.4) by Tom Igoe, bug fix from Noah Shibley
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8 | |||
9 | Drives a unipolar or bipolar stepper motor using 2 wires or 4 wires
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10 | |||
11 | When wiring multiple stepper motors to a microcontroller,
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12 | you quickly run out of output pins, with each motor requiring 4 connections.
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13 | |||
14 | By making use of the fact that at any time two of the four motor
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15 | coils are the inverse of the other two, the number of
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16 | control connections can be reduced from 4 to 2.
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17 | |||
18 | A slightly modified circuit around a Darlington transistor array or an L293 H-bridge
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19 | connects to only 2 microcontroler pins, inverts the signals received,
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20 | and delivers the 4 (2 plus 2 inverted ones) output signals required
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21 | for driving a stepper motor.
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22 | |||
23 | The sequence of control signals for 4 control wires is as follows:
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24 | |||
25 | Step C0 C1 C2 C3
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26 | 1 1 0 1 0
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27 | 2 0 1 1 0
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28 | 3 0 1 0 1
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29 | 4 1 0 0 1
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30 | |||
31 | The sequence of controls signals for 2 control wires is as follows
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32 | (columns C1 and C2 from above):
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33 | |||
34 | Step C0 C1
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35 | 1 0 1
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36 | 2 1 1
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37 | 3 1 0
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38 | 4 0 0
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39 | |||
40 | The circuits can be found at
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41 |
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42 | http://www.arduino.cc/en/Tutorial/Stepper
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43 |
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44 |
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45 | */
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46 | |||
47 | |||
48 | #include "Arduino.h" |
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49 | #include "Stepper.h" |
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50 | |||
51 | /*
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52 | * two-wire constructor.
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53 | * Sets which wires should control the motor.
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54 | */
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55 | Stepper::Stepper(int number_of_steps, int motor_pin_1, int motor_pin_2) |
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56 | { |
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57 | this->step_number = 0; // which step the motor is on |
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58 | this->speed = 0; // the motor speed, in revolutions per minute |
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59 | this->direction = 0; // motor direction |
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60 | this->last_step_time = 0; // time stamp in ms of the last step taken |
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61 | this->number_of_steps = number_of_steps; // total number of steps for this motor |
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62 | |||
63 | // Arduino pins for the motor control connection:
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64 | this->motor_pin_1 = motor_pin_1;
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65 | this->motor_pin_2 = motor_pin_2;
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66 | |||
67 | // setup the pins on the microcontroller:
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68 | pinMode(this->motor_pin_1, OUTPUT);
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69 | pinMode(this->motor_pin_2, OUTPUT);
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70 | |||
71 | // When there are only 2 pins, set the other two to 0:
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72 | this->motor_pin_3 = 0; |
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73 | this->motor_pin_4 = 0; |
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74 | |||
75 | // pin_count is used by the stepMotor() method:
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76 | this->pin_count = 2; |
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77 | } |
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78 | |||
79 | |||
80 | /*
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81 | * constructor for four-pin version
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82 | * Sets which wires should control the motor.
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83 | */
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84 | |||
85 | Stepper::Stepper(int number_of_steps, int motor_pin_1, int motor_pin_2, int motor_pin_3, int motor_pin_4) |
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86 | { |
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87 | this->step_number = 0; // which step the motor is on |
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88 | this->speed = 0; // the motor speed, in revolutions per minute |
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89 | this->direction = 0; // motor direction |
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90 | this->last_step_time = 0; // time stamp in ms of the last step taken |
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91 | this->number_of_steps = number_of_steps; // total number of steps for this motor |
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92 | |||
93 | // Arduino pins for the motor control connection:
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94 | this->motor_pin_1 = motor_pin_1;
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95 | this->motor_pin_2 = motor_pin_2;
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96 | this->motor_pin_3 = motor_pin_3;
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97 | this->motor_pin_4 = motor_pin_4;
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98 | |||
99 | // setup the pins on the microcontroller:
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100 | pinMode(this->motor_pin_1, OUTPUT);
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101 | pinMode(this->motor_pin_2, OUTPUT);
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102 | pinMode(this->motor_pin_3, OUTPUT);
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103 | pinMode(this->motor_pin_4, OUTPUT);
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104 | |||
105 | // pin_count is used by the stepMotor() method:
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106 | this->pin_count = 4; |
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107 | } |
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108 | |||
109 | /*
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110 | Sets the speed in revs per minute
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111 | |||
112 | */
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113 | void Stepper::setSpeed(long whatSpeed) |
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114 | { |
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115 | this->step_delay = 60L * 1000L / this->number_of_steps / whatSpeed; |
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116 | } |
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117 | |||
118 | /*
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119 | Moves the motor steps_to_move steps. If the number is negative,
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120 | the motor moves in the reverse direction.
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121 | */
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122 | void Stepper::step(int steps_to_move) |
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123 | { |
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124 | int steps_left = abs(steps_to_move); // how many steps to take |
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125 | |||
126 | // determine direction based on whether steps_to_mode is + or -:
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127 | if (steps_to_move > 0) {this->direction = 1;} |
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128 | if (steps_to_move < 0) {this->direction = 0;} |
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129 | |||
130 | |||
131 | // decrement the number of steps, moving one step each time:
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132 | while(steps_left > 0) { |
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133 | // move only if the appropriate delay has passed:
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134 | if (millis() - this->last_step_time >= this->step_delay) { |
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135 | // get the timeStamp of when you stepped:
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136 | this->last_step_time = millis();
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137 | // increment or decrement the step number,
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138 | // depending on direction:
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139 | if (this->direction == 1) { |
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140 | this->step_number++;
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141 | if (this->step_number == this->number_of_steps) { |
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142 | this->step_number = 0; |
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143 | } |
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144 | } |
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145 | else {
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146 | if (this->step_number == 0) { |
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147 | this->step_number = this->number_of_steps; |
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148 | } |
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149 | this->step_number--;
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150 | } |
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151 | // decrement the steps left:
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152 | steps_left--; |
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153 | // step the motor to step number 0, 1, 2, or 3:
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154 | stepMotor(this->step_number % 4); |
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155 | } |
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156 | } |
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157 | } |
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158 | |||
159 | /*
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160 | * Moves the motor forward or backwards.
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161 | */
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162 | void Stepper::stepMotor(int thisStep) |
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163 | { |
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164 | if (this->pin_count == 2) { |
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165 | switch (thisStep) {
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166 | case 0: /* 01 */ |
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167 | digitalWrite(motor_pin_1, LOW); |
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168 | digitalWrite(motor_pin_2, HIGH); |
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169 | break;
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170 | case 1: /* 11 */ |
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171 | digitalWrite(motor_pin_1, HIGH); |
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172 | digitalWrite(motor_pin_2, HIGH); |
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173 | break;
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174 | case 2: /* 10 */ |
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175 | digitalWrite(motor_pin_1, HIGH); |
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176 | digitalWrite(motor_pin_2, LOW); |
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177 | break;
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178 | case 3: /* 00 */ |
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179 | digitalWrite(motor_pin_1, LOW); |
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180 | digitalWrite(motor_pin_2, LOW); |
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181 | break;
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182 | } |
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183 | } |
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184 | if (this->pin_count == 4) { |
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185 | switch (thisStep) {
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186 | case 0: // 1010 |
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187 | digitalWrite(motor_pin_1, HIGH); |
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188 | digitalWrite(motor_pin_2, LOW); |
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189 | digitalWrite(motor_pin_3, HIGH); |
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190 | digitalWrite(motor_pin_4, LOW); |
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191 | break;
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192 | case 1: // 0110 |
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193 | digitalWrite(motor_pin_1, LOW); |
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194 | digitalWrite(motor_pin_2, HIGH); |
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195 | digitalWrite(motor_pin_3, HIGH); |
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196 | digitalWrite(motor_pin_4, LOW); |
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197 | break;
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198 | case 2: //0101 |
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199 | digitalWrite(motor_pin_1, LOW); |
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200 | digitalWrite(motor_pin_2, HIGH); |
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201 | digitalWrite(motor_pin_3, LOW); |
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202 | digitalWrite(motor_pin_4, HIGH); |
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203 | break;
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204 | case 3: //1001 |
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205 | digitalWrite(motor_pin_1, HIGH); |
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206 | digitalWrite(motor_pin_2, LOW); |
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207 | digitalWrite(motor_pin_3, LOW); |
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208 | digitalWrite(motor_pin_4, HIGH); |
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209 | break;
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210 | } |
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211 | } |
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212 | } |
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213 | |||
214 | /*
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215 | version() returns the version of the library:
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216 | */
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217 | int Stepper::version(void) |
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218 | { |
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219 | return 4; |
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220 | } |