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UCOS II port for TM4C123G microcontroller

Nishanth Sivanandam
Prodigy 30 points


I ported uCOS II for TM4C123G micro-controller.

uCOS II works great.

But when interrupt is used, it goes to lowest priority idle task.

It is not scheduling user defined highest priority task.

I use the following code for servicing interrupt.

void  BSP_IntHandler (CPU_INT16U  src_nbr)
{
    CPU_FNCT_VOID  isr;
    CPU_SR_ALLOC();

    CPU_CRITICAL_ENTER();                                       
    OSIntEnter();
    CPU_CRITICAL_EXIT();

    OSIntExit();                                                
}

  • 0
    TI__Guru**** 244410 points

    Hello Nishanth,

    Is the BSP_IntHandler registered in the interrupt vector table for the TM4C123 device?

    Regards

    Amit

  • 0 in reply to Amit Ashara
    Prodigy 30 points

    Yes, BSP_IntHandler is registered in the interrupt vector table.

    Microcontroller enter the ISR and executes the ISR instructions.

    When ISR calls OSIntExit() function, it should  shedule the highest priority task.

    But it always enters lowest priority Idle task (which is an infinite loop code).

  • 0 in reply to Nishanth Sivanandam
    TI__Guru**** 244410 points

    Hello Nishanth,

    In the UCOS II source code for bsp_int.c shows something like this

    void  BSP_IntHandler (CPU_INT16U  src_nbr)
    {
        CPU_FNCT_VOID  isr;
        CPU_SR_ALLOC();

        CPU_CRITICAL_ENTER();                                       /* Tell the OS that we are starting an ISR            */
        OSIntEnter();
        CPU_CRITICAL_EXIT();

        if (src_nbr < BSP_INT_ID_MAX) {
            isr = BSP_IntVectTbl[src_nbr];
            if (isr != (CPU_FNCT_VOID)0) {
                isr();
            }
        }

        OSIntExit();                                                /* Tell the OS that we are leaving the ISR            */
    }

    Regards

    Amit

  • 0 in reply to Amit Ashara
    Prodigy 30 points

    Yes.

    if (src_nbr < BSP_INT_ID_MAX) {
        isr = BSP_IntVectTbl[src_nbr];
        if (isr != (CPU_FNCT_VOID)0) {
            isr();
        }
    }

    But what this code do?