nrf54l15 bluetooth stretching spi clock

[DannyDS]

Hello all,

I have an nrf54l15 on a custom board, I am having issues getting a reliable SPI clock signal when using BLE advertisements

This is the clock and correct MOSI data I am expecting to see when BLE advertisements are disabled

This is the clock signal I get when BLE advertisement is enabled

Ive stripped the program of everything other than BLE and a SPI transaction to rule anything else out.

Thanks for any suggestions.

Thanks,

Danny

[Vidar Berg]

Hi,

Good to hear, thanks for confirming that this was the issue.The nrf_sys_event_request_global_constlat() API is reference counted, so when it's called from the application, it prevents other modules such as the Bluetooth controller, from switching back to low-power mode until the application releases its request by calling nrf_sys_event_release_global_constlat(). The Bluetooth controller is using the constant latency sub power mode during BLE events to reduce interrupt latency.