root / trunk / code / projects / libdragonfly / buzzer.c @ 1452
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| 1 | /**
|
|---|---|
| 2 | * Copyright (c) 2007 Colony Project |
| 3 | * |
| 4 | * Permission is hereby granted, free of charge, to any person |
| 5 | * obtaining a copy of this software and associated documentation |
| 6 | * files (the "Software"), to deal in the Software without |
| 7 | * restriction, including without limitation the rights to use, |
| 8 | * copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 9 | * copies of the Software, and to permit persons to whom the |
| 10 | * Software is furnished to do so, subject to the following |
| 11 | * conditions: |
| 12 | * |
| 13 | * The above copyright notice and this permission notice shall be |
| 14 | * included in all copies or substantial portions of the Software. |
| 15 | * |
| 16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| 17 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES |
| 18 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
| 19 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT |
| 20 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, |
| 21 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| 22 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
| 23 | * OTHER DEALINGS IN THE SOFTWARE. |
| 24 | **/ |
| 25 | |
| 26 | |
| 27 | /**
|
| 28 | * @file buzzer |
| 29 | * @brief Functions for using the buzzer |
| 30 | * |
| 31 | * Contains functions for using the buzzer. |
| 32 | * |
| 33 | * @author Colony Project, CMU Robotics Club |
| 34 | * |
| 35 | * much taken from FWR's firefly library (author: Tom Lauwers) |
| 36 | **/ |
| 37 | |
| 38 | #include <avr/io.h> |
| 39 | #include "buzzer.h" |
| 40 | #include "time.h" |
| 41 | |
| 42 | /**
|
| 43 | * @defgroup buzzer Buzzer |
| 44 | * @brief Functions for controlling the buzzer. |
| 45 | * Functions for controlling the buzzer. Include |
| 46 | * buzzer.h to access these functions. |
| 47 | * @{
|
| 48 | **/ |
| 49 | |
| 50 | /**
|
| 51 | * Initializes the buzzer. Must be called before any other buzzer |
| 52 | * function may be used. |
| 53 | **/ |
| 54 | void buzzer_init( void ) |
| 55 | {
|
| 56 | //NOTE: This is mostly handled by buzzer_Set_val for now
|
| 57 | // Set pin B7 to output - B7 is buzzer pin
|
| 58 | //DDRB |= _BV(DDB7);
|
| 59 | //Fast PWM Mode, Clear OCR0 on compare match and set at bottom, clock/64
|
| 60 | //TCCR2 = _BV(COM20) | _BV(WGM21) | _BV(CS22);
|
| 61 | } |
| 62 | |
| 63 | /**
|
| 64 | * Sets the value of the buzzer's pitch. |
| 65 | * Higher values are lower frequencies. |
| 66 | * |
| 67 | * @param buzz_value the value to set the buzzer's frequency too, |
| 68 | * in the range 0-255 |
| 69 | * |
| 70 | * @see buzzer_init, buzzer_set_freq, buzzer_off |
| 71 | **/ |
| 72 | void buzzer_set_val(unsigned int buzz_value) |
| 73 | {
|
| 74 | TCCR2 = _BV(COM20) | _BV(WGM21) | _BV(CS22); |
| 75 | DDRB |= _BV(DDB7); |
| 76 | OCR2 = buzz_value; |
| 77 | } |
| 78 | |
| 79 | /**
|
| 80 | * Sets the buzzer frequency. Usage of constants such as C4 |
| 81 | * is highly recommended as input to this function. |
| 82 | * buzzer_init must be called before this function may |
| 83 | * be used. |
| 84 | * |
| 85 | * @param buzz_freq the frequency to set the buzzer to |
| 86 | * |
| 87 | * @see buzzer_init, buzzer_set_val, buzzer_off |
| 88 | **/ |
| 89 | void buzzer_set_freq(unsigned int buzz_freq) |
| 90 | {
|
| 91 | int buzz_value;
|
| 92 | |
| 93 | buzz_value = 62500/buzz_freq - 1; |
| 94 | |
| 95 | if(buzz_value > 255){ |
| 96 | buzz_value = 255;
|
| 97 | }else if(buzz_value < 0){ |
| 98 | buzz_value = 0;
|
| 99 | } |
| 100 | |
| 101 | buzzer_set_val(buzz_value); |
| 102 | } |
| 103 | |
| 104 | /**
|
| 105 | * Plays the specified frequency for the specified |
| 106 | * amount of time. This function blocks execution |
| 107 | * until the time is completed. buzzer_init must be |
| 108 | * called before this function can be used. |
| 109 | * |
| 110 | * @param ms the time in milliseconds to play the frequency |
| 111 | * @param buzz_freq the frequency to play |
| 112 | * |
| 113 | * @see buzzer_init, buzzer_set_freq |
| 114 | **/ |
| 115 | void buzzer_chirp(unsigned int ms, unsigned int buzz_freq) |
| 116 | {
|
| 117 | buzzer_set_freq(buzz_freq); |
| 118 | delay_ms(ms); |
| 119 | buzzer_off(); |
| 120 | } |
| 121 | |
| 122 | /**
|
| 123 | * Turns off the buzzer by disabling the timer0 clock. |
| 124 | * |
| 125 | * @see buzzer_init |
| 126 | **/ |
| 127 | void buzzer_off()
|
| 128 | {
|
| 129 | // Disable clock, to halt counter
|
| 130 | TCCR2 &= 0xF8;//0b11111000; |
| 131 | |
| 132 | // Set buzzer pin low in case it's high
|
| 133 | PORTB &= 0xBF;//0b10111111; |
| 134 | } |
| 135 | |
| 136 | /** @} **/ // end buzzer group |
| 137 |