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Concerto "SysTick Control and Status Register" Count Flag

Mauro Fantina
Genius 3800 points

Hello.

I'm using Cortex-M3 processor.

I want to test systick count flag.

I use the following code:

bool isSysTickElapsed() { return HWREGBITW(NVIC_ST_CTRL,16)==1; }

but it doesn't work: the processor skip the program flow.

 

 

  • 0
    TI__Mastermind 20850 points

    Hi Mauro,

    What is the disassembly generated by the compiler for that line of code

  • 0 in reply to Vishal_Coelho
    Genius 3800 points

                SysTickElapsed:
    0x20001B04:   4903     LDR             R1, $C$CON12
    0x20001B06:   6809     LDR             R1, [R1]
    0x20001B08:   2000     MOV             R0, #0x0
    0x20001B0A:   2901     CMP             R1, #0x1
    0x20001B0C:   D100     BNE             $C$L4
    0x20001B0E:   2001     MOV             R0, #0x1

    ... finally I use this solution ...

    tBoolean SysTickElapsed()
    {
             #define maskbit (x,y) (HWREG(x)&(1<<(y))) 

            return maskbit(NVIC_ST_CTRL,16)!=0;
    }

    ... but I prefer to use TI macros

     

  • 0 in reply to Mauro Fantina
    TI__Mastermind 22025 points

    Mauro,

    The HWREGBITW macros make use of a special part of the memory map to access an individual bit in RAM.  Only the RAMs and peripherals are accessable through this bit-banded address space.  The NVIC (which lies at 0xE000E000) isn't included in the bit-banded memory and thus cannot be accessed with the HWREGBITW macro.  Your macro will work fine though and is just as good as something a TI'er would write.

    Trey