Radio events clock

[Davide]

Hi, I'm doing some measurement on the radio peripheral of the nRF52840 using the generated events and a timer which is set to run at 16MHz. Radio events and Start/Capture Tasks of the timer are managed through the PPI. With such configuration can I expect to measure the time interval between radio events with 1/16MHz accuracy? From some preliminary evaluation I only get a granularity of 8MHz. Any idea?

PS: If useful I'm using SD140 with a connection established.

Thank you, Davide.

[Davide]

Yes, I get odd and even values out of the timer in the general case, but the interval between RXREADY and ADDRESS is even 99% of the times: the measurement noise, which is there, doesn't make odd values. I cannot change the address size because I'm working with Bluetooth and softdevice s140, I don't think I can change address size keeping the softdevice working.

I don't know if it can be the nature of the radio, I'm not into CMOS radio design actually...but it wouldn't surprise me if it is (symbol rate is 1Mbit, clock is 16MHz, there may be some rounding somewhere, I don't know).