Using ONLY 32MHz crystal?

[Michal Zacharias]

Hello, is it possible to use JUST 32MHz crystal, i.e. WITHOUT using the 16Mhz crystal?

Thank you

[Håkon Alseth]

Hi,

Yes, you can use a 32MHz crystal. This must then be set in the NRF_CLOCK->XTAL_FREQ register (see reference manual, chapter 7). The MCU starts up on RC oscillator (16M), then automatically switches when the external crystal is started and running. Note that the core will still run on 16M, as it will be divided internally in the chip.

The advantage of using 32M xtal is the physical size, as they are smaller than 16M crystals.

Best regards Håkon

[Michal Zacharias]

Wow, that was ultra fast, thank you :) If you don't mind, I will exploit your "ultra fastness" even more :)

[list=1] Can I use BLE and standard BL 2.1 at the same time with JUST 32MHz crystal? [/list]

[Håkon Alseth]

No problem, happy to help :)

We only have BLE/ANT and proprietary products, we do not have any classic bluetooth products, unfortunately.. Nordic has a background with ultra-low power radios, designed to run on a coin cell battery (CR2032 and so on).

Classic bluetooth (v2.1) is not very ultra-low power, so we're not really competing on that league.

Best regards Håkon

[Michal Zacharias]

Hmm, so no dual mode on nRF51822? That complicates things for me. We could use connection to phones without BL Smart. Pity :(