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msp430f4132 /oscillator issue

Anubhav Gupta
Expert 1130 points
Other Parts Discussed in Thread: MSP430F4132

At prsent we are working on msp430F4132 and are facing problem in accessing UART interface.

We are using 32khz external crystal as ossilatior and giving mclk = 7.99 Mhz frequency

by the formula:

 

 

 

WDTCTL = WDTPW+WDTHOLD;

// Stop watchdog timer

wait(100);

SCFI0 |= FN_4;

// x2 DCO freq, 8MHz nominal DCO

SCFQCTL = 121;

// (121+1) x 32768 x 2 = 7.99 Mhz

FLL_CTL0 =0;  // as intialise to zero before using

FLL_CTL0 |= DCOPLUS + XCAP0PF; //During debugging thevalue is coming as 0x83

 

 As we were doing debugging and found that LFOF, DCOF bits in FLL_CTL1 are getting set automatically indicating Following errors.

 1>LFOF Bit 1 LFXT1 low frequency oscillator fault

                 0 No fault condition present

                1 Fault condition present

2>DCOF Bit 0 DCO oscillator fault

              0 No fault condition present

           1 Fault condition present thanks

Plz suggest in this regard 

thanks and regard

 

  • 0
    Guru 227245 points

    It may take several 100 milliseconds before a 32kHz crystal oscillates properly. Before that, the LFOF bit may be set and remain set.

    As for the DCOF, it is set if the FLL has reached bottom or top DCO setting  (DCOx==0 or DCOx==31), so it cannot be adjusted further. It will go away if you select either a different RSEL setting or (if the RSEL settign is okay) once the LFXT1 has finally stabilized and the FLL adjusts the DCO to match the stabilized XT1 frequency (until then, the FLL will try to adjust the DCo to the current XT1 frequency, possibly driving it down to minimum setting, causing DCOF).

     

     

  • 0 in reply to Jens-Michael Gross
    Expert 1130 points

    Michael,

     

    THanks for this help.

     

    Regards

    Anubhav

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