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/*
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 * metronome.c:
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 *        Simple test for the PiFace interface board.
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 *
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 * Copyright (c) 2012-2013 Gordon Henderson. <projects@drogon.net>
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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 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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 *
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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 License
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 *    along with wiringPi.  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 <stdlib.h>
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#include <string.h>
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#include <wiringPi.h>
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#include <piFace.h>
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#define        PIFACE        200
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/*
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 * middleA:
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 *        Play middle A (on the relays - yea!)
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 *********************************************************************************
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 */
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static void middleA (void)
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{
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  unsigned int next ;
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  for (;;)
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  {
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    next = micros () + 1136 ;
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    digitalWrite (PIFACE + 0, 0)  ;
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    digitalWrite (PIFACE + 1, 0)  ;
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    while (micros () < next)
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      delayMicroseconds (1) ;
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    next = micros () + 1137 ;
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    digitalWrite (PIFACE + 0, 1)  ;
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    digitalWrite (PIFACE + 1, 1)  ;
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    while (micros () < next)
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      delayMicroseconds (1) ;
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  }
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}
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int main (int argc, char *argv [])
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{
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  int bpm, msPerBeat, state = 0 ;
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  unsigned int end ;
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  printf ("Raspberry Pi PiFace Metronome\n") ;
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  printf ("=============================\n") ;
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  piHiPri (50) ;
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  wiringPiSetupSys () ;        // Needed for timing functions
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  piFaceSetup      (PIFACE) ;
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  if (argc != 2)
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  {
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    printf ("Usage: %s <beates per minute>\n", argv [0]) ;
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    exit (1) ;
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  }
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  if (strcmp (argv [1], "a") == 0)
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    middleA () ;
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  bpm = atoi (argv [1]) ;
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  if ((bpm < 40) || (bpm > 208))
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  {
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    printf ("%s range is 40 through 208 beats per minute\n", argv [0]) ;
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    exit (1) ;
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  }
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  msPerBeat = 60000 / bpm  ;
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// Main loop:
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//        Put some random LED pairs up for a few seconds, then blank ...
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  for (;;)
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  {
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    end = millis ()  + msPerBeat ;
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    digitalWrite (PIFACE + 0, state)  ;
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    digitalWrite (PIFACE + 1, state)  ;
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    while (millis () < end)
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      delayMicroseconds (500) ;
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    state ^= 1 ;
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  }
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  return 0 ;
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}