• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 82 subscribers
  • Views 493 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Internal vs external oscillator?

Richard Cooke
Expert 1530 points
Other Parts Discussed in Thread: TMS320F28027F

HI,

Is there any gothcas to using the internal oscillator vs using an external crystal?  The LaunchPad schematic dated 4/2/2012 shows a 12MHz crystal connected to pins 45 & 46 but on the actual TMS320F28027F board I have doesn't use the external crystal.  My application will be mostly motor control so will I be OK using the internal clock?  Is it temperature sensitive?  My application won't be doing any complicated communication but it will be operating at times up to 45C - 60C.

Thanks,

Richard Cooke

  • 0
    TI__Guru 60865 points

    Hi Richard,

    At 60C the oscillator may drift up to around 1.5%.  

    If you integrate internal temperature sensor sampling into your ADC conversion code, then pass the results periodically to a TI provided function, the frequency drift can be compensated to within 1%.  

    If you need better accuracy than this, you will need to use an external crystal oscillator.