DCOCLK, MCLK and SMCLK relation

Hi,

I need a Timer based delay functions and wrote the followings.

 (msp430F5529; CCS Version: 5.3.0.00090; FET430UIF; XTAL1 32768Hz ; XTAL2 4MHz)

int main(void)

{

    WDTCTL = WDTPW | WDTHOLD;     // Stop watchdog timer

    // Basic GPIO initialization

    Board_init();

    // Set Vcore to accomodate for max. allowed system speed

    SetVCore(3);

    // Use 32.768kHz XTAL as reference

    LFXT_Start(XT1DRIVE_0);

    // Set system clock to max (25MHz)

    Init_FLL_Settle(25000, 762);

    SFRIFG1 = 0;

    SFRIE1 |= OFIE;

    Clear_Int16_Flag(StatusFlag_1,AllFlags);

    Set_Int16_Flag(StatusFlag_1,PowerMode);

    Set_Int16_Flag(StatusFlag_1,ShowRtcOnLCD);

    *ActiveModeTimeout = 10;

    TimeOut_Us=0;

    TimeOut_Ms=0;

    // Globally enable interrupts

    __enable_interrupt();

    Test_Delay();

    while(1)

    {….

// Timer0 A0 interrupt service routine

#pragma vector=TIMER0_A0_VECTOR

__interrupt void TIMER0_A0_ISR(void)

{

       if(TimeOut_Us)

       {

             TimeOut_Us--;

       }

       else if(TimeOut_Ms)

       {

             TimeOut_Ms--;

       }

       else

       {

             Set_Int16_Flag(StatusFlag_1,TimerTimeOut);

             TA0CCTL0 &= ~CCIE;

       }

}

void Test_Delay (void)

{

       uint32_t i;

       for(i =0 ;i<10000;i++)

       {

             CLK_HIGH;

             Delay_10Us(1);

             CLK_LOW;

             Delay_10Us(1);

       }

       for(i =0 ;i<1000;i++)

       {

             CLK_HIGH;

             Delay_Ms(1);

             CLK_LOW;

             Delay_Ms(1);

       }

       for(i =0 ;i<6;i++)

       {

             CLK_HIGH;

             Delay_s(1);

             CLK_LOW;

             Delay_s(1);

       }

}

void Delay_10Us(uint32_t Time)

{

    TimeOut_Us=Time;

    TimeOut_Ms=0;

    TA0CCTL0 = CCIE;                          // CCR0 interrupt enabled

    TA0CCR0 = 250;

    TA0CTL = TASSEL_2 + MC_1 + TACLR;         // SMCLK, upmode, clear TAR

    while(!Status_Int16_Flag(StatusFlag_1,TimerTimeOut));

    Clear_Int16_Flag(StatusFlag_1,TimerTimeOut);

}

void Delay_Ms(uint32_t Time)

{

    TimeOut_Us=0;

    TimeOut_Ms=Time;

    TA0CCTL0 = CCIE;                          // CCR0 interrupt enabled

    TA0CCR0 = 25000;

    TA0CTL = TASSEL_2 + MC_1 + TACLR;         // SMCLK, upmode, clear TAR

    while(!Status_Int16_Flag(StatusFlag_1,TimerTimeOut));

    Clear_Int16_Flag(StatusFlag_1,TimerTimeOut);

}

void Delay_s(uint32_t Time)

{

    TimeOut_Us=0;

    TimeOut_Ms=Time*1000;

    TA0CCTL0 = CCIE;                          // CCR0 interrupt enabled

    TA0CCR0 = 25000;

    TA0CTL = TASSEL_2 + MC_1 + TACLR;         // SMCLK, upmode, clear TAR

    while(!Status_Int16_Flag(StatusFlag_1,TimerTimeOut));

    Clear_Int16_Flag(StatusFlag_1,TimerTimeOut);

}

And I got the following results.

The UCS register that I copy at run time are in debug mode;

0x000160 --> 10F0 0060 117C 0000 0033 0000 C10D 0C10 0707 0000 0000

From SLAU208M–June 2008 document chapter 5, page 164 I got the formula as;

fDCOCLK = D × (N + 1) × (fFLLREFCLK ÷ n) 

As seen form the register my;

D -> FLLD = 2

N+1 -> FLLN+1 = 381

fFLLREFCLK -> Xtal1 = 32768 (I mentioned at the top)

n -> FLLREFDIV = 1

Fdco = 2x381(32768/1)= 24969216 =~ 25 Mhz, and SMCLK source is DCOCLK (SELS = 011b)

I couldn’t understand why I got the result two times longer than I expected in Delay_10Us() and Delay_Ms() routines but not in Delay_s() ?

Thanks and Kind regards.