Can't access the Main function!

Hi community:

Now i encounter a really strange problem.

I develop a nios system. It contains SDram, Sram, Flash, and other module. There is no error while i compile it in SOPC and Quartus.

When i start a Hello LED project in NIOS IDE, the Alt_main is the entry of the program, everything goes well. No matter i Debug this program in both of the Ram(Sram, SDram) , or i download the .elf to the FLASH and let the program start from FLASH, the LED program runs pretty well.

BUT, when i start a new project HELLO WORLD, the main is the entry , trouble comes out!! (This HELLO WORLD project can only print a string "HELLO" using the stdout. )

The compile process finishes without any error. But after i press the DEBUG button, the program seems keeping "running" without stop in the Main function. And the "Step into, Step over, Step run" icon is gray that can't be pressed.

I just wonder where is the current PC. So i press the "Suspend" button. The PC jump between alt_irq.h and alt_irq_handler.c over and over.

In detail, the PC always jump from this section below in alt_irq.h

static ALT_INLINE alt_u32 ALT_ALWAYS_INLINE alt_irq_pending (void)

{

alt_u32 active;

NIOS2_READ_IPENDING (active);

return active;

}

to this section below in alt_irq_hander.c

void alt_irq_handler (void)

{

alt_u32 active;

alt_u32 mask;

alt_u32 i;

/*

* Notify the operating system that we are at interrupt level.

*/

ALT_OS_INT_ENTER();

/*

* Obtain from the interrupt controller a bit list of pending interrupts,

* and then process the highest priority interrupt. This process loops,

* loading the active interrupt list on each pass until alt_irq_pending()

* return zero.

*

* The maximum interrupt latency for the highest priority interrupt is

* reduced by finding out which interrupts are pending as late as possible.

* Consider the case where the high priority interupt is asserted during

* the interrupt entry sequence for a lower priority interrupt to see why

* this is the case.

*/

active = alt_irq_pending ();

do

{

i = 0;

mask = 1;

/*

* Test each bit in turn looking for an active interrupt. Once one is

* found, the interrupt handler asigned by a call to alt_irq_register() is

* called to clear the interrupt condition.

*/

do

{

if (active & mask)

{

alt_irq.handler(alt_irq.context, i);

break;

}

mask <<= 1;

i++;

} while (1);

active = alt_irq_pending ();

} while (active);

/*

* Notify the operating system that interrupt processing is complete.

*/

ALT_OS_INT_EXIT();

}

and once go over the if(active & mask) in loop

do

{

if (active & mask)

{

alt_irq.handler(alt_irq.context, i);

break;

}

mask <<= 1;

i++;

} while (1);

the next time will go into the if(active & mask) and break.

and now the pc return to the section i mentioned first time in alt_irq.h

static ALT_INLINE alt_u32 ALT_ALWAYS_INLINE alt_irq_pending (void)

{

alt_u32 active;

NIOS2_READ_IPENDING (active);

return active;

}

So, here comes out a infinite loop. And the program will never go to the Main() function.

Why? And how to fix it?

I would like to offer some information further more.

1). The SDRAM, SRAM, FLASH works! Because in the HELLO_LED program, i let the program located in the SDRAM, SRAM and the program can run.

2). This situation is not all along. I mean the HELLO_WORLD program did work in the first time i debug it. But from i debug it in the next day till now, it is dead.

Please give me some advice, or solution.

I will reply the information you needed as soon as possible.

Thanks all of U. http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/smile.gif http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/smile.gif

Kevin.Lee