Hello,

I'd like to know if you can help me. I port the new free rtos version in a new Cortex-M3 project in IAR. There is no call in my created task and it is stalled in vPortStartFirstTask()

vPortStartFirstTask
/* Use the NVIC offset register to locate the stack. */
ldr r0, =0xE000ED08
ldr r0, [r0]
ldr r0, [r0]
/* Set the msp back to the start of the stack. */
msr msp, r0
/* Call SVC to start the first task. */
svc 0 <<<<<<<<<<<<<<<<<<< STOP HERE

What does it mean?

Thanks

Check the vector table, do you have vPortSVCHandler installed as the SVC handler? Look at the file startup_ewarm.c in Demo\CORTEX_LM3Sxxxx_IAR_Keil for an example.

Yes I have this handler in the vector. I wonder if global interrupts are disabled!

Regards

Interrupts should be disabled at that point, the svc instruction is synchronous and will execute even when interrupts are disabled.

I got the same problem with 5.30 of Free RTOS. The vector table looks like this:

__attribute__ ((section(".isr_vector")))
void (* const g_pfnVectors[])(void) =
{
(void (*)(void))((unsigned long)pulStack + sizeof(pulStack)),
// The initial stack pointer
ResetISR, // The reset handler
NmiSR, // The NMI handler
FaultISR, // The hard fault handler
IntDefaultHandler, // The MPU fault handler
IntDefaultHandler, // The bus fault handler
IntDefaultHandler, // The usage fault handler
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
vPortSVCHandler,// SVCall handler
IntDefaultHandler, // Debug monitor handler
0, // Reserved
xPortPendSVHandler, // The PendSV handler
xPortSysTickHandler, // The SysTick handler
IntDefaultHandler, // GPIO Port A

...

It should work, but cpu stucks at svc command in vPortStartFirstTask.
Can anyone help?

OK, i found the Problem with SVC Command in the Cortex-M3.

It is a general problem while debugging with GDB and openocd. During Step-wise debugging, interrupts are disabled. SVC command causes an interrupt, so the command doesn't work during stepping.

I found several suggestion in openOCD forums that i should enable interrupts again with "monitor cortex_m3 maskisr off" in the gdb console. This didn't work.

After 2 days of searching a solution, it has shown that the problem was a wrong openOCD and GDB configuration. (It seems that 99% all problems are openOCD config problems)

Now i use openocd from the YAGARTO Homepage ( r1888+patch) with the following openocd Configuration files: interface/luminary.cfg target/lm3s6965.cfg, and following Startup code for GDB:

target extended-remote localhost:3333
monitor soft_reset_halt
load
break main
continue

Every works now. After startup troubles, the Luminary Cortex-M3 µCs + Codesourcery Lite + FreeRTOS + openOCD + Eclipse works great.