What could make BLE sample applications not work, but radio works ok?

RE: What could make BLE sample applications not work, but radio works ok?

Ole Morten — Mon, 19 Aug 2013 08:30:22 GMT

This is a good question, so I posted it separately and answered it. Please have a look here: https://devzone.nordicsemi.com/index.php/what-low-frequency-clock-sources-can-i-use

RE: What could make BLE sample applications not work, but radio works ok?

Alex — Wed, 14 Aug 2013 02:11:40 GMT

Thank you Ole!

Looks like the external crystal was the problem. Yes we have a crystal on our board, and the ble sample apps try to use it by default with BLE_STACK_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_20_PPM, ...).

Changed that to BLE_STACK_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_SYNTH_250_PPM, ...) and Bluetooth now works. Nice!

Before, the only symptom of a problem was that there was no Bluetooth, the apps ran fine in a debugger and did not seem to hang, also there were no errors. Is there a way to detect such a condition?

Could you explain the NRF_CLOCK_LFCLKSRC_RC_* settings? What are the drawbacks to using the SYNTH clock?

RE: What could make BLE sample applications not work, but radio works ok?

Ole Morten — Tue, 13 Aug 2013 04:21:32 GMT

My best guess is the low frequency clock settings. If you try to enable the softdevice, telling it to use an external crystal, if you don't have any external crystal, it will hang. I'd therefore suggest that you try changing the clock source to RC, to see if it helps.

This could be worth doing even if you have an external crystal, since there could be something else with the crystal causing trouble.

If this is not the problem, it would be very helpful with a little further description than "it doesn't work". :-) (i.e. what exactly happens, have you tried running with the debugger, does it hang, where if so and so on.)