Re: [ECOS] Scheduler Problem

[Iztok Zupet <iz at vsr dot si>]

On Monday 13 October 2003 13:20, James Yates wrote:
> I have just ported eCos to my own custom SH2 platform and I am now at the
> point of  getting a simple app up and running. I have a bootloader running
> on my board which copies the executable from flash to RAM, sets the CPU VBR
> to the correct location and jumps to the address held in the first entry of
> the table. My app starts in cyg_user_start where I can print some
> diagnostic out of the serial port. I am infact using the example app code
> from the "Embedded Software Development with eCos" book. This creates 2
> threads, sets them to resume when the scheduler then exits cyq_user_start
> where as I understand it, the scheduler is then started. After a couple of
> seconds, a load of rubbish is printed out of the serial portand then
> nothing else. It would appear that the first thread is starting and
> something is going horribly wrong but I am not sure what.
>
>    Has anyone had any similar problems in this area or can offer any
> suggestions?
>
> Example code below:
>
> void thread_a( cyg_addrword_t data )
> {
> 	// Store the data value passed in for this thread.
> 	int msg = (int)data;
>
> 	diag_printf("Thread A Start\n" );
>
> 	while( 1 )
> 	{
> 		// Increment the thread a count.
> 		thread_a_count++;
>
> 		// Send out a message to the diagnostic port.
> 		diag_printf( "Thread A, count: %d  message: %d\n", thread_a_count, msg );
>
> 		// Delay for 1 second.
> 		cyg_thread_delay( 100 );
>
> 		// Signal thread B using the semaphore.
> 		cyg_semaphore_post( &sem_signal_thread );
> 	}
> }
>
> void thread_b( cyg_addrword_t data )
> {
> 	// Store the data value passed in for this thread.
> 	int msg = (int)data;
>
> 	diag_printf("Thread B Start\n" );
>
> 	while( 1 )
> 	{
> 		// Signal thread B using the semaphore.
> 		cyg_semaphore_wait( &sem_signal_thread );
>
> 		// Send out a message to the diagnostic port.
> 		diag_printf( "Thread B, message: %d\n", msg );
> 	}
> }
>
> void cyg_user_start( void )
> {
> 	// Initialize the count for thread a.
> 	thread_a_count = 0;
>
> 	// It wouldn't be much of a basic example if some
> 	// kind of hello message wasn't output.
> 	diag_printf( "Hello eCos World!!!\n" );
>
> 	// Initialize the semaphore with a count of zero,
> 	// prior to creating the threads.
> 	cyg_semaphore_init( &sem_signal_thread, 0 );
>
> 	diag_printf( "Point 2\n" );
>
> 	//
> 	// Create our two threads.
> 	//
> 	cyg_thread_create(
> 			THREAD_PRIORITY,
> 			thread_a,
> 			(cyg_addrword_t) 75,
> 			"Thread A",
> 			(void *)thread_a_stack,
> 			THREAD_STACK_SIZE,
> 		    &thread_a_hdl,
> 		    &thread_a_obj );
>
> 	cyg_thread_create(
> 			THREAD_PRIORITY,
> 			thread_b,
> 			(cyg_addrword_t) 68,
> 			"Thread B",
> 			(void *)thread_b_stack,
> 			THREAD_STACK_SIZE,
> 		    &thread_b_hdl,
> 		    &thread_b_obj );
>
> 	// Resume the threads so they start when the scheduler
> 	// begins.
>  	diag_printf( "Point 3\n" );
> 	cyg_thread_resume( thread_a_hdl );
> 	cyg_thread_resume( thread_b_hdl );

You should start the scheduler here, otherwise it's never started:

    	Cyg_Scheduler::scheduler.start(); 	// This function never returns

>
>  	diag_printf( "Point 4\n" );
>
> }

Regards
Iztok

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