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/*
ChibiOS/RT - Copyright (C) 2006-2007 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 "lpc214x.h"
#include "board.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)
void InitBuzzer(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.
}
static void stop(void *p) {
TC *tc = T1Base;
StopCounter(tc);
chEvtBroadcastI(&BuzzerSilentEventSource);
}
void PlaySound(int freq, systime_t duration) {
static VirtualTimer bvt;
TC *tc = T1Base;
chSysLock();
if (chVTIsArmedI(&bvt)) { // If a sound is already being played
chVTResetI(&bvt); // then aborts it.
StopCounter(tc);
}
tc->TC_MR0 = tc->TC_MR1 = (PCLK / (freq * 2));
StartCounter(tc);
chVTSetI(&bvt, duration, stop, NULL);
chSysUnlock();
}
void PlaySoundWait(int 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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