nrf51822 module with a single 16mhz crystal

[moenad]

I have these nrf51822 modules, bought them from this company Wireless Tag, it's a chinese company I guess but I just noticed that the modules only have a single 16 MHZ oscillator hooked up (should have checked before).

After reading part of the documentation, I noticed that the BLE stack requires both crystals 32 and 16mhz, I want to make sure what's the consequences of having only a single 16mhz crystal on the board?

I'm having problem programming them using OpenOCD and STLink-v2 (I'll post another question about it).

[MartinBL]

Hi!

An external 32.768 Hz crystal is optional. You can also use the internal RC 32.768 Hz oscillator or synthesize the frequency from the 16 MHz clock. Read this great post for more info.

I am not sure if this is what you meant, but you do not need a 32 MHz clock. When designing a board you can chose either a 32 MHz or a 16 MHz crystal. And an external high frequency clock like this is mandatory, as opposed to the external low frequency clock.

So you are all good. Your board should work fine as it is.

[moenad]

ok great than, thank you. I still have another question about programming it with openOCD, posted it right now, hopefully it would be great if you can help out.