AnalogInput5.cpp

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

#include "../hubolib.h"

using namespace HuboLib;

/*
Compile and link: 
    g++ AnalogInput5.cpp -L../ -lhubo -lpthread -lrt -o AnalogInput5.out
Run:
    sudo ./AnalogInput5.out
Purpose:
    Wait reading buffered samples until the reading buffer is filled.
    First we define which channels to be read (channel 0), then we wait prior to reading its values.
*/

int main(void)
{
    // Initialize the library once in your program.
    if (!Initialize())
    {
        printf ("Error: Initialize\n");
        return 1;
    }
    
    // Define channel 0 to be read (set to 1) all other channels (set to 0) are not read from the ADC.
    unsigned short overSampling[MAX_MCP3x08_CHANNELS] = { 1, 0, 0, 0, 0, 0, 0, 0 };
    Set_MCP3x08_Oversampling (overSampling);
    
    // Wait as long until we have valid values in the buffer.
    Wait_For_MCP3x08_Buffered_Values();
    
    int             channel = 0;
    unsigned long   adcCount; 
    double          volt;
    for (int i=0; i<20; i++)
    {
        // Read channel 0 and output its value.
        if (Get_AI_Channel (channel, adcCount, volt))
        {
            printf ("Channel=%d   ADC count=0x%02lX   Volts=%lf\n", channel, adcCount, volt);
            // Since ADC channels are buffered your'e referring to the buffered values instead of directly  
            // reading them from the ADC. The buffer might need some time to first get filled before you get a true
            // result of a measuring value. Here the call to Initialize() is too close in time for a first 
            // usage of the Get_AI_Channel() call. That's why the first few samples will show "0".
        }
        else 
        {
            printf ("Error: Get_AI_Channel\n");
        }

        usleep(1000);
    }
    
    // Free library resources.
    Uninitialize();
    
    return 0;
}