Softdevice crashes/disappears after connection speed test

[schef]

Hi guys, i was testing the connection speed from android in conjunction with advertisement time to see what will work better in my production code.

The result were:

• ~3s on 100ms adv time
• ~7s on 300ms adv time

I have some other sensor readings, adc, flash and timer. I was monitoring firmware status over RTT and what happend was:

after 100 connections the device was unvisible but the code on RTT side was further executing. No reboot or any sign of crash.

This happend multiple times. Do you have any suggestions? Is there somekind of watchdog for Softdevice? Or am i totaly looking at the wrong rabbits hole?

Thanks

[FormerMember]

From what I understand, you are measuring the time it takes to connect when a device is advertising.

1) The longer a connection interval is, the longer time it will take for a scanner to pick up the signals. Especially if the scanner is not scanning continuously. It is hard to know if Android is scanning continuously. To create a continuous scanner, you can for example use pc-ble-driver.

2) How does the production code work? Does it disconnect immediately after a connect? And after 100 connections, the devices stop to advertise?

[schef]

The android makes 100 connections and immediately after it connects it disconnects. I know that characteristics discovery takes some time also.

On some mobile phones after making this test the device stops to advertise.

[FormerMember]

Okay, I see. Which phones and Android version are problematic? And which phones and Android version work fine?

[schef]

samsung galaxy s6 - 6.0.1 - crashed softdevice on nrf52

[FormerMember]

Thanks!

When starting to advertise, do you check the error code returned by sd_ble_gap_adv_start()?

Before starting to advertise, do you wait for BLE_GAP_EVT_DISCONNECT before calling sd_ble_gap_adv_start()?

Do you generally check the error codes?

[schef]

I used an example for a starting point which uses APP_ERROR_CHECK(err_code). The app isn't in debug mode any more so i guess that it should restart if anything goes wrong.