Please Help!

Kernel
1

timothybean wrote on Wednesday, March 04, 2009:

The OS and everything completely crashes and stops running. 

Here is the scenario:

Task A uses the SPI bus.
Task B also uses the SPI bus.
Again with Task C.

Task A can take the semaphore, no problems. Always works.

If Task B or Task C tries to take the semaphore, the whole OS crashes. Every time, even is Task A is not doing anything at the moment.

2

prithwee wrote on Wednesday, March 04, 2009:

Make sure that you have released the semaphore in Task-A. xSemaphoreGive( xSemaphore );

Have a look @ user documnetaion in www.freertos.org

Example usage:

xSemaphoreHandle xSemaphore = NULL;

void vATask( void * pvParameters )
{
    // Create the semaphore to guard a shared resource.  As we are using
    // the semaphore for mutual exclusion we create a mutex semaphore
    // rather than a binary semaphore.
    xSemaphore = xSemaphoreCreateMutex();

    if( xSemaphore != NULL )
    {
        if( xSemaphoreGive( xSemaphore ) != pdTRUE )
        {
            // We would expect this call to fail because we cannot give
            // a semaphore without first “taking” it!
        }
        // Obtain the semaphore - don’t block if the semaphore is not
        // immediately available.
        if( xSemaphoreTake( xSemaphore, ( portTickType ) 0 ) )
        {
            // We now have the semaphore and can access the shared resource.
            // …
            // We have finished accessing the shared resource so can free the
            // semaphore.
            if( xSemaphoreGive( xSemaphore ) != pdTRUE )
            {
                // We would not expect this call to fail because we must have
                // obtained the semaphore to get here.
            }
        }
    }
}

Regards,
Prithwee

3

timothybean wrote on Friday, March 06, 2009:

I will put the code in to check, but I do give it back in all instances.

Any idea why the whole OS crashes though?

4

prithwee wrote on Friday, March 06, 2009:

Did you locked your SPI Read/Write properly?

Post your sample code here… It may help you!!!

5

timothybean wrote on Saturday, March 07, 2009:

I will put the code in to check, but I do give it back in all instances.

Any idea why the whole OS crashes though?