CC2541 and 32khz crystal

Santhosh Thodupunoori

Other Parts Discussed in Thread: CC2541

Hi,

We are targeting a thin application with CC2541 - plastic card with CC2541 embedded. From docs and SDK, we understand that CC2541 needs a 32Mhz and a 32khz crystal. Is there anyway we can avoid using the 32khz crystal? This crystal does not fit within the thickness constraints of our application. Is this crystal only needed for idle mode? Is there any way we can avoid this crystal?

Thanks

over 14 years ago

0 Santhosh Thodupunoori over 14 years ago

Prodigy 20 points

Ok found the answer.

External 32khz is needed only for power mode 3, otherwise there is an internal 32khz rc osc. In short, we are good.

0 hec over 14 years ago in reply to Santhosh Thodupunoori

TI__Genius 10955 points

This is not correct. The 32 kHz crystal is needed for power mode 1 and 2. In power mode 3, it will be switched off. If you want to use the BLE stack with power modes, you will need the 32 kHz crystal.

0 Steve Chen1 over 13 years ago in reply to hec

Prodigy 190 points

Hi,

If we do not wish to use the 32KHz crystal, will the CC2541 still work? I mean does the fundamental hardware design of the CC2541 requires 32KHz crystal? Or is this just a software stack function?

BR,

Steve

0 Aslak N. over 13 years ago in reply to Steve Chen1

TI__Mastermind 23440 points

Hi Steve,

Please post new questions in new posts.

You can use the chip without an external crystal. However it will not be BLE compliant (requires 500ppm sleep clock), and the stack will not work because of timing deviations.

Best regards,
Aslak

0 Steve Chen1 over 13 years ago in reply to Aslak N.

Prodigy 190 points

Hi Aslak,

Thank! I have posted my question in the below link

http://e2e.ti.com/support/low_power_rf/f/538/t/258847.aspx

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CC2541 and 32khz crystal