Delay from GPIOTE Event until a Task is started over PPi on nRF52

[Pascal Künzi]

Hi all,

I measured the delays between a GPIOTE event and a Task (in this case toggling with another GPIOTE) through PPI.

The results are showed below:

For the nRF52 it's arround 380ns.

The same measurements were done with the nRF51.

Here it's arround 250ns.

Originally i am coming from counting the pulses of a high frequency signal ~3.5MHz which works fine on the nRF51 but doesn't work on the nRF52.

I couldn't find any information about this topic. So i was wondering:

1. where that difference is coming from
2. if these delays are accurate and valid for other tasks too
3. what happens if too many pulses appear?

On the nRF52 the output pulses look as followed:

It looks like the chip can only handle some but not all of them which leads to weird on-off times.

With the nRF51 it looks like that:

All of the input pulses are processed and generate the expected output.

I hope you can help me and that there is a possibility to get the same results on the nRF52 without adding a flip flop to divide the HF-signal by two.

[MartinBL]

Hi, as of now we actually don't have a good explanation why the nRF51 accepts higher frequencies than the nRF52. We need to do some simulations to figure that out, but unfortunately the designers are very busy these days and that might take a while. If this is of grave importance to you please open a support ticket on MyPage, link to this thread, and express your concerns there.