Implementing a semaphore in tirtos_01_basic tutorial

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/*
 *  ======== lab1-main.c ========
 */

/* XDCtools Header files */
#include <xdc/std.h>
#include <xdc/cfg/global.h>
#include <xdc/runtime/System.h>

/* BIOS Header files */
#include <ti/sysbios/BIOS.h>
#include <ti/sysbios/knl/Task.h>
#include <ti/sysbios/knl/Clock.h>
#include <ti/sysbios/knl/Semaphore.h>   // added 2/8/16

/* TI-RTOS Header files */
#include <ti/drivers/PIN.h>
#include <ti/drivers/pin/PINCC26XX.h>   // added 2/4/16



/* Example/Board Header files */
#include "Board.h"

/* Driverlib CPU functions, used here for CPUdelay*/
#include <driverlib/cpu.h>

/* Could be anything, like computing primes */
#define FakeBlockingSlowWork()   CPUdelay(12e6)
#define FakeBlockingFastWork()   CPUdelay(3e6)


/* Pin driver handles */
static PIN_Handle pinHandle;

/* Global memory storage for a PIN_Config table */
static PIN_State pinState;

Task_Struct workTask;
Task_Struct urgentTask;
static uint8_t workTaskStack[256];

/*
 * Initial pin configuration table
 *   - LEDs Board_LED1 & Board_LED2 are off after the pin table is initialized.
 *   - Button is set to input with pull-up.
 */
PIN_Config pinTable[] = {
    Board_LED1 | PIN_GPIO_OUTPUT_EN | PIN_GPIO_LOW | PIN_PUSHPULL | PIN_DRVSTR_MAX,
    Board_LED2 | PIN_GPIO_OUTPUT_EN | PIN_GPIO_LOW | PIN_PUSHPULL | PIN_DRVSTR_MAX,
    Board_KEY_RIGHT | PIN_INPUT_EN | PIN_PULLUP,
    PIN_TERMINATE
};

void doWork(void)
{
	PIN_setOutputValue(pinHandle, Board_LED1, 1);
    FakeBlockingSlowWork(); /* Pretend to do something useful but time-consuming */
	PIN_setOutputValue(pinHandle, Board_LED1, 0);
}

Void workTaskFunc(UArg arg0, UArg arg1)
{
    while (1)
    {

    	/* Do work */
    	doWork();

    	/* Wait a while, because doWork should be a periodic thing, not continuous.*/
    	// CPUdelay(24e6);
    	Task_sleep(  (1000E-3) / (Clock_tickPeriod * (1E-6) )  );
    }
}

void pinInterruptHandler(PIN_Handle handle, PIN_Id pinId)
{

    // see the semaphore declared by the cfg file
    Semaphore_post( urgentWorkSem );
}

void doUrgentWork()
{
    while( 1)
    {
        Semaphore_pend( urgentWorkSem, BIOS_WAIT_FOREVER );

        PIN_setOutputValue(pinHandle, Board_LED2, 1);
        FakeBlockingSlowWork(); /* Pretend to do something useful but time-consuming */
        PIN_setOutputValue(pinHandle, Board_LED2, 0);
    }
}

/*
 *  ======== main ========
 *
 */
int main(void)
{


    /* Call board init functions */
    PIN_init(BoardGpioInitTable);

    /* Open LED pins */
    pinHandle = PIN_open(&pinState, pinTable);
    if(!pinHandle) {
        System_abort("Error initializing board pins\n");
    }

    PIN_registerIntCb(pinHandle, pinInterruptHandler);
    PIN_setInterrupt(pinHandle, Board_KEY_RIGHT | PIN_IRQ_NEGEDGE);


    /* Set up the led1 task */
	Task_Params workTaskParams;
	Task_Params_init(&workTaskParams);
	workTaskParams.stackSize = 256;
	workTaskParams.priority = 1;
	workTaskParams.stack = &workTaskStack;

	Task_construct(&workTask, workTaskFunc, &workTaskParams, NULL);

	// the debugger exits on first launch after adding this statement
	//doUrgentWork();

    /* Start kernel. */
    BIOS_start();

    return (0);
}