DigitalInput5.cpp

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#include <stdio.h>
#include <unistd.h>

#include "../hubolib.h"
#include "../hubocfg.h" // Required for changing default I2C device.

using namespace HuboLib;

/*
Compile and link: 
    g++ DigitalInput5.cpp -L../ -lhubo -lpthread -lrt -o DigitalInput5.out
Run:
    sudo ./DigitalInput5.out
Purpose:
    Let's get notified whenever a digital input changes.
    The program will terminate when digital input 2 is lowered to ground.
*/

// This function is called whenever a digital input changes.
void DIChangedCallback (unsigned char changedInputs, unsigned char allInputs);

bool bTerminate = false;

int main(void)
{
    // If required - set the I2C device to work with. The Raspberry Pi uses "/dev/i2c-1" which is default, the Banana Pi uses "/dev/i2c-0"
    #ifdef BPI
        g_I2CConfig.m_sI2CDevice = "/dev/i2c-0";
    #endif

    // Initialize the library once in your program.
    if (!Initialize())
    {
        printf ("Error: Initialize\n");
        return 1;
    }
    
    // After initialization the callback can be registered.
    Register_DIChangedCallback (DIChangedCallback);
    
    while (!bTerminate) 
    {
        usleep (1000);
    } 

    // It's good programming style to de-register the callback.
    Unregister_DIChangedCallback (DIChangedCallback);

    // Free library resources.
    Uninitialize();
    
    return 0;
}

void DIChangedCallback (unsigned char changedInputs, unsigned char allInputs)
{
    // This function is called from the background thread running at high priority. 
    // Thus lengthy operations (such as prinf) should not be performed as they 
    // could exceed the time slice for the cycle tick. 
    // Note that the synchronisation with the main thread is missing for the bool 
    // variable bTerminate and should be done in a proper application.
    printf ("DIChangedCallback changed=0x%02X  new=0x%02X\n", changedInputs, allInputs);

    // Has the input 2 changed?
    if (changedInputs & 4)
        bTerminate = true;
}