RCSocket.cpp

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#include <stdio.h>
#include <assert.h>

#include "../hubolib.h"
#include "CSC5262.h"

using namespace HuboLib;
using namespace BCM2835;

/*
Compile and link:
    g++ RCSocket.cpp CSC5262.cpp -L../ -lhubo -lpthread -lrt -o RCSocket.out
Run:
    sudo ./RCSocket.out <system-code> <socket number> <0|1>
Purpose:
    The demo shows how the GPIO interface can be used to bit bang an output in order to
    use an 433MHz transmission module for controlling a RC socket.
*/


// Switch Coding (x is not being used and should be set to 0)
// System-Code          Receiver-Socket
// x x x 1 2 3 4 5      x x x A B C D E

// Example 1
// System-Code          Receiver-Socket
// x x x 1 2 3 4 5      x x x A B C D E
// 0 0 0 0 0 1 0 1      0 0 0 0 0 0 1 0
// 0x05                 0x02
// SwitchSocket(0x05,   0x02, true... ) switches socket D of system 00101 on.
// SwitchSocket(0x05,   0x02, false...) switches socket D of system 00101 off.

// Example 2
// System-Code          Receiver-Socket
// x x x 1 2 3 4 5      x x x A B C D E
// 0 0 0 1 0 0 1 1      0 0 0 1 0 0 0 0
// 0x13                 0x10
// SwitchSocket(0x13,   0x10, true... ) switches socket A of system 10011 on.
// SwitchSocket(0x13,   0x10, false...) switches socket A of system 10011 off.


bool strToUChar(char* str, unsigned char& value);
void BoostThreadPriority();


int main(int argc, char *argv[])
{
    unsigned char systemCode, socketNumber, value;
    if (argc!=4 || !strToUChar(argv[1], systemCode) || !strToUChar(argv[2], socketNumber) || !strToUChar(argv[3], value))
    {
        printf (
                "Usage:\n"
                "RCSocket.out <system-code> <socket number> <0|1>\n"
                "system-code: 0..31\n"
                "socket number: 0..31 (whereas A=16, B=8, C=4, D=2 and E=1)\n"
                "0=off, 1=on\n"
                );
        return -1;
    }

    // This program requires high priority in order to successfully bit bang over the GPIO.
    BoostThreadPriority();

    // If this call doesn't return true then we must not use the GPIO part of Hubo library!
    if (!IsGPIOInitialized ())
    {
        printf ("GPIO not properly initialized. Are you running the program as sudoer?\n");
        return -1;
    }

    // Let's use a bit-length of 350µs (that's what the remote control sends) and BCM2835 pin 17 (= GPIO0).
    // Experiments have shown a minimum of 150µs and a maximum of 580µs for the bit length.
    CSC5262 mySwitch(350, 17);

    // While the switches seem to require at least 3 successive transmissions in a series - repeating it
    // at least 4 times seems to improve transmission stability. After 10 retries in total we stop.
    mySwitch.SwitchSocket(systemCode, socketNumber, value>0, 4, 10);

    return 0;
}

#include <pthread.h>    
#include <assert.h>    
void BoostThreadPriority()
{
    // Scheduling params.
    sched_param param;
    int         policy;
    int         ret;
    pthread_t   threadHandle = pthread_self();

    // Get current scheduling parameters of thread.
    ret             = pthread_getschedparam (threadHandle, &policy, &param);
    assert (ret == 0);

    // Set scheduling parameters of thread to real time values (FIFO scheduling type and max prio).
    policy               = SCHED_FIFO; // SCHED_RR;
    param.sched_priority = sched_get_priority_max(policy); // New max priority for new scheduling concept.
    ret                  = pthread_setschedparam(threadHandle, policy, &param);
    assert (ret == 0);
}

bool strToUChar(char* str, unsigned char& value)
{
    unsigned long v;
    if (sscanf(str, "%lu", &v) != 1)
        return false;
    value = (unsigned char)v;
    if (value != (unsigned long)v)
        return false;
    return true;
}