nrf52832 Crystal frequency

[Eric]

The manual clearly states that the external HFXO should be 32MHz. However, if one would like to have precise 16kHz on the PDM and I2S interfaces a 32.768MHz crystal is required.

So, will things start to fail/degrade if I use a 32.768MHz crystal instead ?

[AmbystomaLabs]

You are confusing the 32.768kHz crystal with the 32MHz crystal. So that is kilohertz vs. megahertz.

The 32.768kHz crystal drives the RTC and normally sleep/wake functions of the nRF.

The 32MHz crystal is the frequency reference for the 2.4GHz radio and is required for radio operations. It is also generally the frequency reference for the processor. However there is also an internal RC based 32MHz oscillator that can be used to run the processor and peripherals. It uses less power than the external crystal and is the default for most application level work unless the accuracy of the external crystal is required.

32MHz not kilohertz is the reference for the PDM and i2s. But if you for some reason choose to run off of the internal RC 32MHz the accuracy is not great. Therefore it is best to run off the 32MHz external crystal.