wiringPi_Blueberry/examples/PiFace/metro.c

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2023-08-11 15:53:17 +08:00
/*
* metronome.c:
* Simple test for the PiFace interface board.
*
* Copyright (c) 2012-2013 Gordon Henderson. <projects@drogon.net>
***********************************************************************
* This file is part of wiringPi:
* https://projects.drogon.net/raspberry-pi/wiringpi/
*
* wiringPi is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* wiringPi 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with wiringPi. If not, see <http://www.gnu.org/licenses/>.
***********************************************************************
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wiringPi.h>
#include <piFace.h>
#define PIFACE 200
/*
* middleA:
* Play middle A (on the relays - yea!)
*********************************************************************************
*/
static void middleA (void)
{
unsigned int next ;
for (;;)
{
next = micros () + 1136 ;
digitalWrite (PIFACE + 0, 0) ;
digitalWrite (PIFACE + 1, 0) ;
while (micros () < next)
delayMicroseconds (1) ;
next = micros () + 1137 ;
digitalWrite (PIFACE + 0, 1) ;
digitalWrite (PIFACE + 1, 1) ;
while (micros () < next)
delayMicroseconds (1) ;
}
}
int main (int argc, char *argv [])
{
int bpm, msPerBeat, state = 0 ;
unsigned int end ;
printf ("Raspberry Pi PiFace Metronome\n") ;
printf ("=============================\n") ;
piHiPri (50) ;
wiringPiSetupSys () ; // Needed for timing functions
piFaceSetup (PIFACE) ;
if (argc != 2)
{
printf ("Usage: %s <beates per minute>\n", argv [0]) ;
exit (1) ;
}
if (strcmp (argv [1], "a") == 0)
middleA () ;
bpm = atoi (argv [1]) ;
if ((bpm < 40) || (bpm > 208))
{
printf ("%s range is 40 through 208 beats per minute\n", argv [0]) ;
exit (1) ;
}
msPerBeat = 60000 / bpm ;
// Main loop:
// Put some random LED pairs up for a few seconds, then blank ...
for (;;)
{
end = millis () + msPerBeat ;
digitalWrite (PIFACE + 0, state) ;
digitalWrite (PIFACE + 1, state) ;
while (millis () < end)
delayMicroseconds (500) ;
state ^= 1 ;
}
return 0 ;
}