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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Buzzer driver for Olimex LPC-P2148.
* Uses the timer 1 for wave generation and a Virtual Timer for the sound
* duration.
* The driver also generates an event when the sound is done and the buzzer
* goes silent.
*/
#include "ch.h"
#include "hal.h"
#include "buzzer.h"
EventSource BuzzerSilentEventSource;
#define StartCounter(t) ((t)->TC_EMR = 0xF1, (t)->TC_TCR = 1)
#define StopCounter(t) ((t)->TC_EMR = 0, (t)->TC_TCR = 2)
/**
* @brief Buzzer driver initialization.
*/
void buzzInit(void) {
chEvtInit(&BuzzerSilentEventSource);
/*
* Switches P0.12 and P0.13 to MAT1.0 and MAT1.1 functions.
* Enables Timer1 clock.
*/
PINSEL0 &= 0xF0FFFFFF;
PINSEL0 |= 0x0A000000;
PCONP = (PCONP & PCALL) | PCTIM1;
/*
* Timer setup.
*/
TC *tc = T1Base;
StopCounter(tc);
tc->TC_CTCR = 0; /* Clock source is PCLK. */
tc->TC_PR = 0; /* Prescaler disabled. */
tc->TC_MCR = 2; /* Clear TC on match MR0. */
}
/**
* @brief Stops the sound.
*
* @param[in] p pointer to the timer
*/
static void stop(void *p) {
StopCounter((TC *)p);
chEvtBroadcastI(&BuzzerSilentEventSource);
}
/**
* @brief Plays a tone asynchronously.
*
* @param[in] freq approximated tone frequency
* @param[in] duration tone duration in systicks
*/
void buzzPlay(uint32_t freq, systime_t duration) {
static VirtualTimer bvt;
TC *tc = T1Base;
chSysLock();
if (chVTIsArmedI(&bvt)) { /* If a sound is already being */
chVTResetI(&bvt); /* played then aborts it. */
StopCounter(tc);
}
tc->TC_MR0 = tc->TC_MR1 = (PCLK / (freq * 2));
StartCounter(tc);
chVTSetI(&bvt, duration, stop, tc);
chSysUnlock();
}
/**
* @brief Plays a tone.
*
* @param[in] freq approximated tone frequency
* @param[in] duration tone duration in systicks
*/
void buzzPlayWait(uint32_t freq, systime_t duration) {
TC *tc = T1Base;
StopCounter(tc);
tc->TC_MR0 = tc->TC_MR1 = (PCLK / (freq * 2));
StartCounter(tc);
chThdSleep(duration);
StopCounter(tc);
}
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