94 lines
2.5 KiB
C
94 lines
2.5 KiB
C
/*
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ChibiOS/RT - Copyright (C) 2006-2007 Giovanni Di Sirio.
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This file is part of ChibiOS/RT.
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ChibiOS/RT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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ChibiOS/RT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* Buzzer driver for Olimex LPC-P2148.
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* Uses the timer 1 for wave generation and a Virtual Timer for the sound
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* duration.
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* The driver also generates an event when the sound is done and the buzzer
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* goes silent.
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*/
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#include <ch.h>
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#include "lpc214x.h"
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#include "board.h"
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#include "buzzer.h"
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EventSource BuzzerSilentEventSource;
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#define StartCounter(t) ((t)->TC_EMR = 0xF1, (t)->TC_TCR = 1)
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#define StopCounter(t) ((t)->TC_EMR = 0, (t)->TC_TCR = 2)
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void InitBuzzer(void) {
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chEvtInit(&BuzzerSilentEventSource);
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/*
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* Switches P0.12 and P0.13 to MAT1.0 and MAT1.1 functions.
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* Enables Timer1 clock.
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*/
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PINSEL0 &= 0xF0FFFFFF;
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PINSEL0 |= 0x0A000000;
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PCONP = (PCONP & PCALL) | PCTIM1;
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/*
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* Timer setup.
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*/
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TC *tc = T1Base;
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StopCounter(tc);
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tc->TC_CTCR = 0; // Clock source is PCLK.
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tc->TC_PR = 0; // Prescaler disabled.
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tc->TC_MCR = 2; // Clear TC on match MR0.
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}
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static void stop(void *p) {
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TC *tc = T1Base;
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StopCounter(tc);
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chEvtSendI(&BuzzerSilentEventSource);
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}
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void PlaySound(int freq, systime_t duration) {
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static VirtualTimer bvt;
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TC *tc = T1Base;
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chSysLock();
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if (chVTIsArmedI(&bvt)) { // If a sound is already being played
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chVTResetI(&bvt); // then aborts it.
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StopCounter(tc);
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}
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tc->TC_MR0 = tc->TC_MR1 = (PCLK / (freq * 2));
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StartCounter(tc);
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chVTSetI(&bvt, duration, stop, NULL);
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chSysUnlock();
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}
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void PlaySoundWait(int freq, systime_t duration) {
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TC *tc = T1Base;
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StopCounter(tc);
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tc->TC_MR0 = tc->TC_MR1 = (PCLK / (freq * 2));
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StartCounter(tc);
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chThdSleep(duration);
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StopCounter(tc);
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}
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