FanSpeed.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++ FanSpeed.cpp -L../ -lhubo -lpthread -lrt -o FanSpeed.out
Run:
    sudo ./FanSpeed.out
Purpose:
    Simple demo doing sending ON-OFF patterns to a digital output e.g. to control fan speed.
*/

#define FAN_CHANNEL 0
#define WAIT_TIME   10000


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;
    }

    // Set background cycle time to 5ms in order to have the digital IO's being updated every 5ms.
    Set_Cycle_Time(5);
    
    // The pattern to use to update the FAN-CHANNEL IO pin.
//  int channelPattern [10] = {0, 0, 1, -1};        // 33% duty time
//  int channelPattern [10] = {0, 1, -1};           // 50% duty time
//  int channelPattern [10] = {0, 1, 1, -1};        // 66% duty time
    int channelPattern [10] = {0, 1, 1, 1, -1};     // 75% duty time
//  int channelPattern [10] = {1, -1};              // 100% duty time

    // This rover goes round and round.
    int patternRover = 0;
    
    // Cyclic update of the FAN_CHANNEL IO pin.
    while (1)
    {
        int value = channelPattern[patternRover++];
        if (value == -1)
        {
            patternRover = 0;
            continue;
        }
        
        // Set output to new value.
        Set_DO_Channel(FAN_CHANNEL, value);
    
        // Wait a while.
        usleep (WAIT_TIME);
    }
    
    // Free library resources (despite the fact we'll never get here).
    Uninitialize();
    
    return 0;
}