/* * metronome.c: * Simple test for the PiFace interface board. * * Copyright (c) 2012-2013 Gordon Henderson. *********************************************************************** * 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 . *********************************************************************** */ #include #include #include #include #include #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 \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 ; }