root / branches / colonetmk2 / code / projects / libdragonfly / buzzer.c @ 1456
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1 | 241 | bcoltin | /**
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2 | * Copyright (c) 2007 Colony Project
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3 | *
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4 | * Permission is hereby granted, free of charge, to any person
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5 | * obtaining a copy of this software and associated documentation
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6 | * files (the "Software"), to deal in the Software without
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7 | * restriction, including without limitation the rights to use,
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8 | * copy, modify, merge, publish, distribute, sublicense, and/or sell
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9 | * copies of the Software, and to permit persons to whom the
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10 | * Software is furnished to do so, subject to the following
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11 | * conditions:
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12 | *
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13 | * The above copyright notice and this permission notice shall be
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14 | * included in all copies or substantial portions of the Software.
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15 | *
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16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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17 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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18 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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19 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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20 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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21 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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22 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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23 | * OTHER DEALINGS IN THE SOFTWARE.
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24 | **/
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25 | 8 | bcoltin | |
26 | 241 | bcoltin | |
27 | /**
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28 | * @file buzzer
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29 | * @brief Functions for using the buzzer
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30 | *
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31 | * Contains functions for using the buzzer.
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32 | *
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33 | * @author Colony Project, CMU Robotics Club
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34 | *
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35 | * much taken from FWR's firefly library (author: Tom Lauwers)
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36 | **/
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37 | |||
38 | 8 | bcoltin | #include <avr/io.h> |
39 | 1456 | rcahoon | #include "buzzer.h" |
40 | #include "time.h" |
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41 | 8 | bcoltin | |
42 | /**
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43 | * @defgroup buzzer Buzzer
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44 | * @brief Functions for controlling the buzzer.
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45 | * Functions for controlling the buzzer. Include
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46 | * buzzer.h to access these functions.
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47 | * @{
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48 | **/
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49 | |||
50 | /**
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51 | * Initializes the buzzer. Must be called before any other buzzer
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52 | * function may be used.
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53 | **/
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54 | void buzzer_init( void ) |
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55 | { |
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56 | //NOTE: This is mostly handled by buzzer_Set_val for now
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57 | // Set pin B7 to output - B7 is buzzer pin
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58 | //DDRB |= _BV(DDB7);
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59 | //Fast PWM Mode, Clear OCR0 on compare match and set at bottom, clock/64
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60 | //TCCR2 = _BV(COM20) | _BV(WGM21) | _BV(CS22);
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61 | } |
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62 | |||
63 | /**
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64 | * Sets the value of the buzzer's pitch.
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65 | * Higher values are lower frequencies.
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66 | *
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67 | * @param buzz_value the value to set the buzzer's frequency too,
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68 | * in the range 0-255
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69 | *
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70 | * @see buzzer_init, buzzer_set_freq, buzzer_off
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71 | **/
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72 | void buzzer_set_val(unsigned int buzz_value) |
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73 | { |
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74 | TCCR2 = _BV(COM20) | _BV(WGM21) | _BV(CS22); |
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75 | DDRB |= _BV(DDB7); |
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76 | OCR2 = buzz_value; |
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77 | } |
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78 | |||
79 | /**
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80 | * Sets the buzzer frequency. Usage of constants such as C4
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81 | * is highly recommended as input to this function.
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82 | * buzzer_init must be called before this function may
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83 | * be used.
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84 | *
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85 | * @param buzz_freq the frequency to set the buzzer to
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86 | *
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87 | * @see buzzer_init, buzzer_set_val, buzzer_off
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88 | **/
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89 | void buzzer_set_freq(unsigned int buzz_freq) |
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90 | { |
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91 | int buzz_value;
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92 | |||
93 | buzz_value = 62500/buzz_freq - 1; |
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94 | |||
95 | if(buzz_value > 255){ |
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96 | buzz_value = 255;
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97 | }else if(buzz_value < 0){ |
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98 | buzz_value = 0;
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99 | } |
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100 | |||
101 | buzzer_set_val(buzz_value); |
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102 | } |
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103 | |||
104 | /**
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105 | * Plays the specified frequency for the specified
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106 | * amount of time. This function blocks execution
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107 | * until the time is completed. buzzer_init must be
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108 | * called before this function can be used.
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109 | *
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110 | * @param ms the time in milliseconds to play the frequency
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111 | * @param buzz_freq the frequency to play
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112 | *
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113 | * @see buzzer_init, buzzer_set_freq
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114 | **/
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115 | void buzzer_chirp(unsigned int ms, unsigned int buzz_freq) |
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116 | { |
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117 | buzzer_set_freq(buzz_freq); |
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118 | delay_ms(ms); |
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119 | buzzer_off(); |
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120 | } |
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121 | |||
122 | /**
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123 | * Turns off the buzzer by disabling the timer0 clock.
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124 | *
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125 | * @see buzzer_init
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126 | **/
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127 | void buzzer_off()
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128 | { |
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129 | // Disable clock, to halt counter
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130 | TCCR2 &= 0xF8;//0b11111000; |
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131 | |||
132 | // Set buzzer pin low in case it's high
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133 | PORTB &= 0xBF;//0b10111111; |
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134 | } |
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135 | |||
136 | /** @} **/ // end buzzer group |