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.

[Hung Bui]

Hi Davide,

I'm sorry that we are quite short in staff now because of the summer vacation period. I can't to test right now.

It would be very nice if you can provide the firmware so we can reproduce here. I would suggest to have something like:

1. Setting up PPI, connect a GPIOTE EVENT 1 to TIMER TASKS_START

2. Setting up PPI, connect a GPIOTE EVENT 2 to TIMER TASKS_CAPTURE

3. Start a loop, trigger GPIOTE EVENT 1, put some delay , trigger GPIOTE EVENT 2

4. Print out the Captured value and go back to step 3.

This will clearly show the strange behaviour that we only have even capture value.