Semaphore: line 207: assertion failure: A_badContext: bad calling context. Must be called from a Task.

Glenn Vassallo

Other Parts Discussed in Thread: SYSBIOS

I need to call a CC3000 firmware method using a Clock or Timer. Unfortunately when I do this, I get the following error message.

ti.sysbios.knl.Semaphore: line 207: assertion failure: A_badContext: bad calling context. Must be called from a Task.

I know that I am getting this as a Clock creates a SWI thread and a Timer creates a HWI thread. Both of these threads will cause an assertion failure when a semaphore pend is called, which I believe is occurring when I call the CC3000 firmware method mdnsAdvertiser.

I have tried starting the Clock and Timer from within a Task context, but this makes no difference.

Here is my code

void mDNSSend(UArg arg0)
{
	char device_name[] = "DeviceName";

	if ((deviceConnected == TRUE) && (dhcpComplete == TRUE))
	{
		mdnsAdvertiser(1,device_name,strlen(device_name));  //This is where the assertion failure occurs
	}
}

/* Timer task, I have also tried a Clock with a timeout value set, but still get the assertion */
void mDNSSendTask(UArg arg0, UArg arg1)
{
    Error_Block eb;
    Timer_Params timerParams;
    Error_init(&eb);
    Timer_Params_init(&timerParams);
    timerParams.period = 200000; 
    timerHandle = Timer_create(Timer_ANY, mDNSSend, &timerParams, &eb);
    if (timerHandle == NULL)
    {
    	System_abort("Timer create failed");
    }
}

/* mDNSSendTask is created statically in my TI-RTOS config */
/* I have also tried starting dynamically, but get the same result */
var taskParams = new Task.Params();
taskParams.instance.name = "mDNSSendTask";
taskParams.stackSize = 1024;
taskParams.priority = 4;
Program.global.wifiTask = Task.create("&mDNSSendTask", taskParams);

Is there any way I can call the mdnsAdvertiser method with a Clock or Timer?

If there is no way, then how can I call this method on a regular timed basis?

Glenn.

over 11 years ago

0 MarkGrosen over 11 years ago

TI__Expert 4125 points

Glenn,

Even though you are creating the Timer (or Clock) from your task, the callback function that is invoked by Timer (or Clock) will not be running as a Task - this is what is causing the assertion. You need to call your mDNSSend() function from the task directly.

If your timing accuracy is not critical, you could just use Task_sleep():

Void mdnsTask(UArg arg0, UArg arg1)
{
    while (TRUE) {
        Task_sleep(MDNSPERIOD_IN_TICKS);
        mDNSSend(0);
    }
}

If you need better performance, create a Clock object that posts a semaphore:

Void mdnsTask(UArg arg0, UArg arg1)
{
    Semaphore_Handle mdnsSem;
    Clock_Handle mdnsClock;
    Clock_Params clockParams;

    mdnsSem = Semaphore_create(0, NULL, NULL);
    Clock_Params_init(&clockParams);
    clockParams.arg = (UArg)mdnsSem;
    clockParams.period = MDNSPERIOD_IN_TICKS;
    clockParams.startFlag = TRUE;
    mdnsClock = Clock_create(Semaphore_post, MDNSPERIOD_IN_TICKS, &clockParams, NULL);

    while (TRUE) {
        Semaphore_pend(mdnsSem);
        mDNSSend(0);
    }
}

Mark

Void mDNSSendTask(UArg arg0, UArg arg1)

0 Glenn Vassallo over 11 years ago in reply to MarkGrosen

Guru 21435 points

Hi Mark,

Thanks for the great answer and quick response!

Glenn.

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Semaphore: line 207: assertion failure: A_badContext: bad calling context. Must be called from a Task.