Online Power Profiler for BLE: questions and a bug

[9il]

Hello,

Please help me to figure out how to use https://devzone.nordicsemi.com/power/w/opp/2/online-power-profiler-for-bluetooth-le for time interval estimation. I have a few questions.

1. Why does connection event length include 'standby'? What is it?
2. If HF clock is already enabled, will it reduce the connection length by the time of the crystal ramp-up?
3. Why does connection event length include postprocessing? Can post-processing overlap with the next connection event RX or TX operation?

A small related bug report:

nRF5340 has the wrong simulation when RX is set to some value instead of 0. Try to set it to 1, and you will see a massive increase in power consumption. The picture will show the correct char of power consumption. However, the report numbers will be wrong. If you integrate the power chart on the picture, you will see how different it is from the report number of the power consumption.

[Simonr]

Hi

1. This standby current you're seeing in the online power profiler is the standby current before the radio turns on, where the HFCLK is running (consuming ~200µA).

2. Yes, the crystal ramp up won't happen if the crystal is already running.

3. As you can see here, the post processing is SoftDevice timing-critical, so it will not be able to overlap with the next event, as the connection event won't be considered finished before post-processing is completed. It is added in the Power Profiler as it is considered part of the connection event.

I have forwarded your bug report to the developers of the tool. Thank you for letting us know!

Best regards,

Simon

[Simonr]

Just got a reply from one of the devs on your bug report.

It's not a bug really. When you set RX to something other than 0 that implies you receive data, so CPU will then run afterwards to do post processing, which is per spec. in BLE. However this isn't reflected well enough in the plot, so the confusion is understandable.

Best regards,

Simon

[9il]

But how the post processing can be so hungry for 5340 while it is so small for nrf52?

[9il]

Thank you, Simonr!

But why is standby is needed as part of connection event?

If HF is always on and we don't need crystal ramp up, do we still need standby as part of connection event?

Kind regards,

Ilia

[9il]

450 vs 773 microA! Please submit the images below to the bug report.