CC2642R: xtal start up between 48M and 32k

Albin Zhang

Part Number: CC2642R

Tool/software:

Hi There,

is the two xtal (48M/32K) startup independent or relevant?

e.g. if customer configure LF to 32k xtal and mount the 32k xtal , but due to some issue, the xtal can't startup normally, will this impact the 48MHz start up?

BR. Albin

3 months ago

0 Toby 3 months ago

TI__Mastermind 34960 points

Hi Albin,

I've notified a HW expert to look into this, they'll be returning soon (around mid next week), please stay tuned.

Thanks,
Toby

0 guoqing wang 3 months ago in reply to Toby

Prodigy 111 points

This matter is very urgent.！！！ Could you please ask the replacement of the expert on leave to answer it?
Another question is added: in the normal operation of BLE, the sudden frequency offset of 32.768K crystal is too large or too small, will it affect the oscillation of 48M crystal?
Does the 48M crystal stop oscillating?

0 Toby 3 months ago in reply to guoqing wang

TI__Mastermind 34960 points

Let me check with internal team.

0 Nima 3 months ago

TI__Genius 14705 points

Hi Albin,

I've re-assigned this thread to a hardware engineer. They should respond to you tomorrow.

Best,

Nima Behmanesh

0 Haiatullah Gholami 3 months ago in reply to guoqing wang

TI__Expert 3630 points

Hi Guoqing,

The LF crystal and HF crystal have two difference oscillator circuit and are independent of each other. The gain and thus the startup time of the 48MHz crystal should not be affected by 32kHz crystal.

Regards,

0 zhegan qi 3 months ago in reply to Haiatullah Gholami

Prodigy 30 points

If the load capacitance matched with the 32K crystal is too small, which parameters of the crystal will be affected, and what adverse consequences will it cause?

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CC2642R: xtal start up between 48M and 32k