nes-proj/platform/avr-ravenlcd/beep.c

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/*
* Copyright (c) 2008 Swedish Institute of Computer Science
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of the copyright holders nor the names of
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
*
* \brief
* This file implements a beep function to emit a beep sound from Raven's
* speaker.
*
* \author
* Mike Vidales mavida404@gmail.com
*
*/
#include "beep.h"
#include "key.h"
/**
* \addtogroup lcd
* \{
*/
/*---------------------------------------------------------------------------*/
/**
* \brief Emits a beep from the Raven's buzzer. This routine simply toggles a port pin
* at an audio frequency, which causes a tone to be emitted from the Raven's speaker.
* The beep consists of two tones at two different frequencies. At the end, the beeper
* port pin is kept low, which causes the speaker amplifier to shut down.
*/
void
beep(void)
{
uint8_t i;
volatile uint8_t j;
/* Turn on the power to the speaker. */
ENTER_DDR |= (1 << PE7);
ENTER_PUR |= (1 << PE7);
/* Setup port pin */
BEEP_DDR |= (1 << BEEP_BIT);
for (i=0;i<100;i++){
/* Toggle port pin */
BEEP_PIN |= (1 << BEEP_BIT);
/* Delay loop */
for (j=0;j<0xff;j++)
;
}
for (i=0;i<100;i++){
/* Toggle port pin */
BEEP_PIN |= (1 << BEEP_BIT);
/* Delay loop */
for (j=0;j<0xa0;j++)
;
}
/* Turn off speaker */
BEEP_PORT &= ~(1 << BEEP_BIT);
ENTER_PUR &= ~(1 << PE7);
}
/** \} */