events.c

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#include <cfg/os.h>

#include <stdio.h>
#include <io.h>

#include <dev/board.h>

#include <sys/thread.h>
#include <sys/timer.h>
#include <sys/event.h>

/*
 * A global event queue, used as a mutex semaphore.
 */
static HANDLE mutex;

/*
 * High priority background thread. 
 */
THREAD(High, arg)
{
    NutThreadSetPriority(32);
    for(;;) {
        puts("Request");
        if (NutEventWait(&mutex, 2000)) {
            puts("Timeout");
        }
        else {
            puts("Acquired");
            NutSleep(2500);
            puts("Release");
            NutEventPost(&mutex);
        }
        NutSleep(1000);
    }
}

/*
 * Low priority background thread. 
 */
THREAD(Low, arg)
{
    NutThreadSetPriority(96);
    for(;;) {
        puts("                  Request");
        if (NutEventWait(&mutex, 3000)) {
            puts("                  Timeout");
        }
        else {
            puts("                  Acquired");
            NutSleep(3500);
            puts("                  Release");
            NutEventPost(&mutex);
        }
    }
}

/*
 * Main application routine. 
 */
int main(void)
{
    uint32_t baud = 115200;

    /*
     * Register the UART device, open it, assign stdout to it and set 
     * the baudrate.
     */
    NutRegisterDevice(&DEV_CONSOLE, 0, 0);
    freopen(DEV_CONSOLE_NAME, "w", stdout);
    _ioctl(_fileno(stdout), UART_SETSPEED, &baud);

    /*
     * Print title.
     */
    puts("\nNut/OS Event Queue Demo");
    puts("High     Main     Low      ");

    /*
     * Post an initial event. This will put the queue into signaled 
     * state and immediately grant the next call to NutEventWait().
     */
    NutEventPost(&mutex);

    /*
     * Start two background threads.
     */
    NutThreadCreate("high", High, 0, 256);
    NutThreadCreate("low", Low, 0, 256);

    for(;;) {
        puts("         Request");
        if (NutEventWait(&mutex, 1000)) {
            puts("         Timeout");
        }
        else {
            puts("         Acquired");
            NutSleep(1500);
            puts("         Release");
            NutEventPost(&mutex);
        }
        NutSleep(1000);
    }
    return 0;
}