startup time of HFCLK and LFCLK

[helen]

Hi Nordic,

Is there any standard about the startup time of 32M and 32.768K crystal oscillator?

For example, if the time is larger than some ms the nRF5340 will work abnormally, e.g.

In the SPEC, I only found the type power up time of 32M in some special conditions.

[Simonr]

Hi

There is no specific hard limit in the product specification, as long as the crystal matches the other specifications of freq. tolerance, load capacitance, etc.

In our legacy BLE stack I know that the SoftDevice will only wait for 1.5ms, and thus the max startup time for the HF crystal is 1.5ms. I have asked internally if this is the case for nRF Connect SDK and SoftDevice Controller as well. My guess is that it is, but I have yet to confirm that.

Best regards,

Simon

[helen]

Hi Simon,

Many thanks and look forward for your reply.

[Simonr]

Yes, the same goes for the nRF Connect SDK. See this page in the documentation for reference.

Best regards,

Simon