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CC2541 without 32.768KHz crystal

Steve Chen1
Prodigy 190 points

Other Parts Discussed in Thread: CC2541

Hi,

If we do not wish to use the 32.768KHz crystal, will the CC2541 still work? I mean does the fundamental hardware design of the CC2541 requires 32.768KHz crystal? Or is this just a software stack function?

 

BR,

 

Steve

  • 0
    TI__Guru** 106705 points

    Hi Steve,

    The CC2541 will work perfectly fine without the 32.768 kHz crystal.

    The crystal is required for accurate sleep timing, so it is only needed if you are planning to be BLE certified and are using low power modes.

    Cheers,

    Fredrik

  • 0 in reply to Fredrik K
    Prodigy 250 points

    Hi

    I have followed this thread and think I know the answer to my question but it would be good to get confirmation.

    I am planning to use the CC2541 as a BLE master and do not require it to enter into low power mode. Am I correct in thinking it does not require a 32.768KHz crystal.

    Regards

    Bill

  • 0 in reply to Bill Garland
    TI__Guru 56590 points

    Hello Bill, 

    You are correct. Just make sure to set the POWER_SAVING to xPOWER_SAVING in the project preprocessor defines so that you are sure that the device will not try to go into sleep which requires the external 32 kHz crystal. 

  • 0 in reply to Eirik V
    Genius 3630 points

    Hi

    Regarding "the device will not try to go into sleep which requires the external 32 kHz crystal. ",

    is this right?

    If yes, if our device needs to be in sleep mode using POWER_SAVING condition, really external 32KHz crystal must be used? We are planning to use internal 32KHz oscillation.

    John

  • 0 in reply to Ji-won Lee
    TI__Guru 56590 points

    With POWER_SAVING enabled in the BLE stack you must have an external 32KHz crystal To be compliant with the BLE specification. If you develop a proprietary code you can use the internal RCOSC to schedule wake up from sleep.