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161 lines
3.7 KiB
161 lines
3.7 KiB
/* |
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* wfi.c: |
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* Wait for Interrupt test program |
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* |
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* This program demonstrates the use of the waitForInterrupt() |
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* function in wiringPi. It listens to a button input on |
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* BCM_GPIO pin 17 (wiringPi pin 0) |
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* |
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* The biggest issue with this method is that it really only works |
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* well in Sys mode. |
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* |
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* Jan 2013: This way of doing things is sort of deprecated now, see |
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* the wiringPiISR() function instead and the isr.c test program here. |
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* |
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* Copyright (c) 2012-2013 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 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 <wiringPi.h> |
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// A 'key' which we can lock and unlock - values are 0 through 3 |
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// This is interpreted internally as a pthread_mutex by wiringPi |
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// which is hiding some of that to make life simple. |
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#define COUNT_KEY 0 |
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// What BCM_GPIO input are we using? |
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#define BUTTON_PIN 17 |
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// Debounce time in mS |
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#define DEBOUNCE_TIME 100 |
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// globalCounter: |
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// Global variable to count interrupts |
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// Should be declared volatile to make sure the compiler doesn't cache it. |
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static volatile int globalCounter = 0 ; |
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/* |
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* waitForIt: |
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* This is a thread created using the wiringPi simplified threading |
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* mechanism. It will wait on an interrupt on the button and increment |
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* a counter. |
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********************************************************************************* |
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*/ |
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PI_THREAD (waitForIt) |
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{ |
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int state = 0 ; |
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int debounceTime = 0 ; |
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(void)piHiPri (10) ; // Set this thread to be high priority |
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for (;;) |
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{ |
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if (waitForInterrupt (BUTTON_PIN, -1) > 0) // Got it |
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{ |
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// Bouncing? |
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if (millis () < debounceTime) |
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{ |
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debounceTime = millis () + DEBOUNCE_TIME ; |
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continue ; |
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} |
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// We have a valid one |
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state ^= 1 ; |
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piLock (COUNT_KEY) ; |
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++globalCounter ; |
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piUnlock (COUNT_KEY) ; |
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// Wait for key to be released |
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while (digitalRead (BUTTON_PIN) == LOW) |
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delay (1) ; |
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debounceTime = millis () + DEBOUNCE_TIME ; |
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} |
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} |
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} |
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/* |
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* setup: |
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* Demo a crude but effective way to initialise the hardware |
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********************************************************************************* |
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*/ |
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void setup (void) |
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{ |
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// Use the gpio program to initialise the hardware |
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// (This is the crude, but effective) |
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system ("gpio edge 17 falling") ; |
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// Setup wiringPi |
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wiringPiSetupSys () ; |
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// Fire off our interrupt handler |
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piThreadCreate (waitForIt) ; |
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} |
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/* |
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* main |
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********************************************************************************* |
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*/ |
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int main (void) |
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{ |
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int lastCounter = 0 ; |
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int myCounter = 0 ; |
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setup () ; |
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for (;;) |
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{ |
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printf ("Waiting ... ") ; fflush (stdout) ; |
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while (myCounter == lastCounter) |
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{ |
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piLock (COUNT_KEY) ; |
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myCounter = globalCounter ; |
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piUnlock (COUNT_KEY) ; |
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delay (500) ; |
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} |
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printf (" Done. myCounter: %5d\n", myCounter) ; |
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lastCounter = myCounter ; |
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} |
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return 0 ; |
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}
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