root / scout_avr / src / stepper.cpp @ a07a0b55
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1 | a07a0b55 | Julian Binder | extern "C" |
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2 | { |
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3 | #include <avr/io.h> |
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4 | } |
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5 | #include "stepper.h" |
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6 | |||
7 | /* Stepper Motor:
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8 | * Provides interface to stepper motor.
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9 | * Can set direction. Outputs pulse to stepper upon call of step func
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10 | * Also provides variable speed sweep
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11 | */
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12 | |||
13 | struct step_t {
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14 | unsigned int speed; // time between steps in ms for sweep. Mininum 40ms |
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15 | unsigned int sweep_us; //time between calls to sweep |
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16 | unsigned int time; |
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17 | int pos; // position in rotation. |
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18 | int dir; // direction. -1 CCW. 1 CW. 0 OFF |
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19 | int ccw;
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20 | int cw;
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21 | } volatile step;
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22 | |||
23 | |||
24 | func step_init(unsigned int call_us) |
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25 | { |
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26 | /* set update time for sweep */
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27 | step.sweep_us = call_us; |
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28 | |||
29 | /* init pos and time to 0 */
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30 | step.pos = 0;
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31 | step.time = 0;
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32 | |||
33 | //set control pins as output
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34 | DDRD |= ((1<<S_STEP) | (1<<S_DIR)); |
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35 | DDRB |= ((1<<S_MS));
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36 | |||
37 | //initiate to full steps
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38 | PORTB &= (~(1<<S_MS));
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39 | |||
40 | //initiate the step pin to be low. stepper steps on low to high
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41 | PORTD &= (~(1<<S_STEP));
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42 | |||
43 | //return function pointer to sweep to be called ever sweep_us uS.
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44 | return &(step_sweep);
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45 | } |
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46 | |||
47 | /* set direction pin */
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48 | void step_dir(int dir) |
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49 | { |
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50 | step.dir = dir; |
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51 | switch(dir)
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52 | { |
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53 | case 1: |
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54 | PORTD |= (1<<S_DIR);
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55 | break;
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56 | case -1: |
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57 | PORTD &= (~(1<<S_DIR));
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58 | break;
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59 | } |
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60 | } |
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61 | |||
62 | void step_halfstep()
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63 | { |
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64 | if(dir==0) return; //do not step if not enabled |
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65 | PORTB |= (1<<S_MS); //enable microstepping |
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66 | _asm_( |
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67 | "nop"
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68 | "nop"
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69 | "nop"
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70 | "nop"
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71 | );//wait 250 ns for microstepping to enable
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72 | PORTD |= (1<<S_STEP); //step once |
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73 | WAIT_US(1); //conform with step timing |
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74 | PORTD &= (~(1<<S_STEP)); //bring the step bin back down |
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75 | PORTB &= (~(1<<S_MS)); //disable microstepping |
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76 | if(dir==1) step.pos++; //keep track of position. 1/2 step so add/sub 1 |
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77 | else step.pos--;
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78 | } |
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79 | |||
80 | void step_fullstep()
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81 | { |
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82 | if(dir==0) return; //do not step if not enabled |
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83 | PORTD |= (1<<S_STEP); //step once |
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84 | WAIT_US(2); //conform with step timing |
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85 | PORTD &= (~(1<<S_STEP)); //bring the step bin back down |
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86 | if(dir==1) step.pos+=2; // full step so add/sub 2 |
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87 | else step.pos-=2; |
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88 | } |
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89 | |||
90 | void step_flush()
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91 | { |
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92 | PORTD &= (~(1<<S_STEP)); //bring the step bin back down |
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93 | } |
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94 | |||
95 | /* tick every speed ms in sweep mode */
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96 | void step_sweep_speed(unsigned int speed) |
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97 | { |
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98 | if(speed<40) step.speed = 40000; |
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99 | else step.speed = speed*1000; |
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100 | } |
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101 | |||
102 | |||
103 | //ccw must be less than 0 and cw must be greater than 0
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104 | void step_sweep_bounds(int ccw, int cw) |
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105 | { |
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106 | step.ccw = ccw; |
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107 | step.cw = cw; |
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108 | } |
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109 | |||
110 | void step_sweep()
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111 | { |
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112 | step.time += sweep_us; |
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113 | if(step.time >= speed)
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114 | { |
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115 | step_halfstep(); |
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116 | if((dir == 1) && (step.cw <= pos)) dir=-1; |
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117 | else if((dir == -1) && (step.ccw >= pos)) dir=1; |
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118 | } |
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119 | } |