root / paintboard / code / motor.c @ c874b753
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1 | 1226c007 | AnsonLinux | #include <avr/io.h> |
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2 | #include "motor.h" |
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3 | #include <stdlib.h> |
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4 | |||
5 | /*
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6 | |||
7 | motor controller. Timer2 is set to phase-correct PWM mode, with 32 prescaler.
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8 | |||
9 | AIN1: PC0
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10 | AIN2: PC1
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11 | PWMA: PB3 (Timer2) (OCRA)
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12 | |||
13 | BIN1: PC2
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14 | BIN2: PC3
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15 | PWMB: PD3 (Timer2) (OCRB)
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16 | |||
17 | */
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18 | |||
19 | int8_t motor1_speed; |
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20 | int8_t motor2_speed; |
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21 | |||
22 | f4a85021 | Tom Mullins | inline uint8_t abs_clamp(int8_t n)
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23 | { |
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24 | if (n == -128) |
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25 | return 127; |
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26 | else if (n < 0) |
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27 | return -n;
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28 | else
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29 | return n;
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30 | } |
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31 | |||
32 | 1226c007 | AnsonLinux | void motor_init(void) |
33 | { |
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34 | |||
35 | // WGM2 0b001 (phase-correct PWM, 8-bit)
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36 | // COM2A 0b10 (clear OCR2A on compare match, set on BOTTOM)
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37 | // COM2B 0b10 (clear OCR2B on compare match, set on BOTTOM)
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38 | // CS2 0b011 (32 prescaler)
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39 | TCCR2A = _BV(WGM20) | _BV(COM2A1) |_BV(COM2B1); |
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40 | TCCR2B = _BV(CS21) | _BV(CS20); |
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41 | OCR2A = 0;
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42 | OCR2B = 0;
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43 | |||
44 | // set output pins
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45 | DDRC |= _BV(PC0) | _BV(PC1) | _BV(PC2) | _BV(PC3); |
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46 | DDRB |= _BV(PB3); |
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47 | DDRD |= _BV(PD3); |
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48 | |||
49 | set_motor1(0);
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50 | set_motor2(0);
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51 | } |
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52 | |||
53 | void set_motor1(int8_t speed)
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54 | /* Speed must be between -127 and 127 */
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55 | { |
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56 | motor1_speed = speed; |
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57 | f4a85021 | Tom Mullins | OCR2A = abs_clamp(speed)*2;
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58 | 1226c007 | AnsonLinux | if(speed>0) //go forwards |
59 | { |
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60 | PORTC |= (1<<PC0);
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61 | f4a85021 | Tom Mullins | PORTC &= ~(1<<PC1);
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62 | 1226c007 | AnsonLinux | PORTC = PORTC & ~(1<<PC1);
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63 | } |
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64 | if(speed<0) //go backwards |
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65 | { |
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66 | f4a85021 | Tom Mullins | PORTC &= ~(1<<PC0);
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67 | 1226c007 | AnsonLinux | PORTC |= (1<<PC1);
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68 | PORTC = PORTC & ~(1<<PC0);
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69 | } |
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70 | if(speed==0) // turn motor off |
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71 | { |
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72 | PORTC = PORTC & ~(1<<PC1);
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73 | PORTC = PORTC & ~(1<<PC0);
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74 | } |
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75 | } |
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76 | |||
77 | void set_motor2(int8_t speed)
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78 | /* Speed must be between -127 and 127 */
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79 | { |
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80 | motor2_speed = speed; |
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81 | f4a85021 | Tom Mullins | OCR2B = abs_clamp(speed)*2;
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82 | 1226c007 | AnsonLinux | if(speed>0) //go forwards |
83 | { |
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84 | PORTC |= (1<<PC2);
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85 | f4a85021 | Tom Mullins | PORTC &= ~(1<<PC3);
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86 | 1226c007 | AnsonLinux | PORTC = PORTC & ~(1<<PC3);
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87 | } |
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88 | if(speed<0) //go backwards |
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89 | { |
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90 | f4a85021 | Tom Mullins | PORTC &= ~(1<<PC2);
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91 | 1226c007 | AnsonLinux | PORTC |= (1<<PC3);
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92 | PORTC = PORTC & ~(1<<PC2);
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93 | } |
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94 | if(speed==0) // turn motor off |
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95 | { |
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96 | PORTC = PORTC & ~(1<<PC3);
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97 | PORTC = PORTC & ~(1<<PC2);
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98 | } |
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99 | } |
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100 | |||
101 | int8_t get_motor1() |
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102 | { |
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103 | return motor1_speed;
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104 | } |
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105 | |||
106 | int8_t get_motor2() |
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107 | { |
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108 | return motor2_speed;
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109 | } |