I am working on designing a board based on the Pro RF schematic and I am wondering what the 32 kHz crystal is used for and if I can leave it out. I’m guessing it’s used for the SAMD21 USB module and since I don’t plan to use that I think I can leave it off. Is the crystal used for anything related to the radio?
Thanks for writing.
The crystal is being used as a clock source for the SAMD21 on this board but it’s possible to use the SAMD21’s internal oscillator if you set the chip up correctly. The blog post in the link below might be helpful if you want to skip the crystal.