root / branches / encoders / code / lib / src / libdragonfly / buzzer.c @ 1345
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1 | 7 | bcoltin | /*
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2 | buzzer.c - Contains the functions necessary for running the buzzer
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3 | |||
4 | author: Robotics Club, Colony Project
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5 | |||
6 | much taken from FWR's firefly library (author: Tom Lauwers)
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7 | */
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8 | |||
9 | #include <avr/io.h> |
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10 | #include <buzzer.h> |
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11 | #include <time.h> |
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12 | |||
13 | /**
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14 | * @defgroup buzzer Buzzer
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15 | * @brief Functions for controlling the buzzer.
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16 | * Functions for controlling the buzzer. Include
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17 | * buzzer.h to access these functions.
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18 | * @{
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19 | **/
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20 | |||
21 | /**
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22 | * Initializes the buzzer. Must be called before any other buzzer
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23 | * function may be used.
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24 | **/
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25 | void buzzer_init( void ) |
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26 | { |
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27 | //NOTE: This is mostly handled by buzzer_Set_val for now
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28 | // Set pin B7 to output - B7 is buzzer pin
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29 | //DDRB |= _BV(DDB7);
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30 | //Fast PWM Mode, Clear OCR0 on compare match and set at bottom, clock/64
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31 | //TCCR2 = _BV(COM20) | _BV(WGM21) | _BV(CS22);
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32 | } |
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33 | |||
34 | /**
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35 | * Sets the value of the buzzer's pitch.
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36 | * Higher values are lower frequencies.
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37 | *
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38 | * @param buzz_value the value to set the buzzer's frequency too,
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39 | * in the range 0-255
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40 | *
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41 | * @see buzzer_init, buzzer_set_freq, buzzer_off
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42 | **/
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43 | void buzzer_set_val(unsigned int buzz_value) |
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44 | { |
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45 | TCCR2 = _BV(COM20) | _BV(WGM21) | _BV(CS22); |
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46 | DDRB |= _BV(DDB7); |
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47 | OCR2 = buzz_value; |
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48 | } |
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49 | |||
50 | /**
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51 | * Sets the buzzer frequency. Usage of constants such as C4
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52 | * is highly recommended as input to this function.
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53 | * buzzer_init must be called before this function may
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54 | * be used.
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55 | *
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56 | * @param buzz_freq the frequency to set the buzzer to
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57 | *
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58 | * @see buzzer_init, buzzer_set_val, buzzer_off
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59 | **/
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60 | void buzzer_set_freq(unsigned int buzz_freq) |
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61 | { |
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62 | int buzz_value;
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63 | |||
64 | buzz_value = 62500/buzz_freq - 1; |
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65 | |||
66 | if(buzz_value > 255){ |
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67 | buzz_value = 255;
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68 | }else if(buzz_value < 0){ |
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69 | buzz_value = 0;
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70 | } |
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71 | |||
72 | buzzer_set_val(buzz_value); |
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73 | } |
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74 | |||
75 | /**
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76 | * Plays the specified frequency for the specified
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77 | * amount of time. This function blocks execution
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78 | * until the time is completed. buzzer_init must be
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79 | * called before this function can be used.
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80 | *
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81 | * @param ms the time in milliseconds to play the frequency
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82 | * @param buzz_freq the frequency to play
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83 | *
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84 | * @see buzzer_init, buzzer_set_freq
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85 | **/
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86 | void buzzer_chirp(unsigned int ms, unsigned int buzz_freq) |
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87 | { |
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88 | buzzer_set_freq(buzz_freq); |
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89 | delay_ms(ms); |
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90 | buzzer_off(); |
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91 | } |
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92 | |||
93 | /**
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94 | * Turns off the buzzer by disabling the timer0 clock.
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95 | *
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96 | * @see buzzer_init
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97 | **/
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98 | void buzzer_off()
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99 | { |
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100 | // Disable clock, to halt counter
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101 | TCCR2 &= 0xF8;//0b11111000; |
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102 | |||
103 | // Set buzzer pin low in case it's high
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104 | PORTB &= 0xBF;//0b10111111; |
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105 | } |
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106 | |||
107 | /** @} **/ // end buzzer group |