mirror of
https://github.com/clockworkpi/WiringPi.git
synced 2025-12-13 00:08:51 +01:00
be04c1bd52
on non Raspbian systems (and even on some Raspbian systems it would appear ): fixed a timing issue on softTone fixed some issues in wiringPisetup introduced when optimising the mmap calls.
122 lines
2.7 KiB
C
122 lines
2.7 KiB
C
/*
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* softTone.c:
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* For that authentic retro sound...
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* Er... A little experiment to produce tones out of a Pi using
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* one (or 2) GPIO pins and a piezeo "speaker" element.
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* (Or a high impedance speaker, but don'y blame me if you blow-up
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* the GPIO pins!)
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* Copyright (c) 2012 Gordon Henderson
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***********************************************************************
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* This file is part of wiringPi:
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* https://projects.drogon.net/raspberry-pi/wiringpi/
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*
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* wiringPi is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* wiringPi 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 Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with wiringPi.
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* If not, see <http://www.gnu.org/licenses/>.
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***********************************************************************
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*/
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#include <stdio.h>
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#include <pthread.h>
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#include "wiringPi.h"
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#include "softTone.h"
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#define MAX_PINS 64
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#define PULSE_TIME 100
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static int frewqs [MAX_PINS] ;
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static int newPin = -1 ;
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/*
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* softToneThread:
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* Thread to do the actual PWM output
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*********************************************************************************
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*/
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static PI_THREAD (softToneThread)
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{
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int pin, frewq, halfPeriod ;
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pin = newPin ;
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newPin = -1 ;
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piHiPri (50) ;
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for (;;)
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{
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frewq = frewqs [pin] ;
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if (frewq == 0)
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delay (1) ;
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else
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{
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halfPeriod = 500000 / frewq ;
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digitalWrite (pin, HIGH) ;
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delayMicroseconds (halfPeriod) ;
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digitalWrite (pin, LOW) ;
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delayMicroseconds (halfPeriod) ;
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}
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}
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return NULL ;
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}
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/*
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* softToneWrite:
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* Write a frequency value to the given pin
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*********************************************************************************
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*/
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void softToneWrite (int pin, int frewq)
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{
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pin &= 63 ;
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/**/ if (frewq < 0)
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frewq = 0 ;
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else if (frewq > 5000) // Max 5KHz
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frewq = 5000 ;
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frewqs [pin] = frewq ;
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}
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/*
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* softToneCreate:
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* Create a new tone thread.
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*********************************************************************************
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*/
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int softToneCreate (int pin)
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{
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int res ;
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pinMode (pin, OUTPUT) ;
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digitalWrite (pin, LOW) ;
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frewqs [pin] = 0 ;
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newPin = pin ;
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res = piThreadCreate (softToneThread) ;
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while (newPin != -1)
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delay (1) ;
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return res ;
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}
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