Change of ADV data in SDK 17

[KTM]

Hello 

We have an application that ADV every second and is based on SDK 14.

We are currently attempting to move to SDK 17. What I have noticed is that if I change and ADV data during advertisement by the help of new API function ble_advertising_advdata_update I see that there will be a delay of ±2 seconds (I see it in air trace) during which there will be no ADV at all.

Even when I configured ADV interval to be 100 milli and data rate change is 1 time at a second I see a delay of 2 seconds over the air until an updated data takes place.

The question is: Is that an expected behaviour? Is there any way to prevent this stop of ADV for 2 seconds?

[Karl Ylvisaker]

Hello,

We are currently attempting to move to SDK 17. What I have noticed is that if I change and ADV data during advertisement by the help of new API function ble_advertising_advdata_update I see that there will be a delay of ±2 seconds (I see it in air trace) during which there will be no ADV at all.

This does sound strange. Is your call to ble_advertising_advdata_update returning any error codes at any point?
The updating of advertising data can be done between every advertisement, and should take effect before the next advertising, or at worst before the second advertising.

Even when I configured ADV interval to be 100 milli and data rate change is 1 time at a second I see a delay of 2 seconds over the air until an updated data takes place.

How are you queueing the updating of the data, through a timer?

Could you make sure that you have DEBUG defined in your preprocessor defines, like shown in the included image?

1 - 2 seconds sounds like you application might be encountering an error and / or resetting. Could you verify if this occurs, that the device resets in this timespan?

Looking forward to resolving this issue together!

Best regards,
Karl

[KTM]

Hello Karl

I ma not hitting app_error_handler and do run with DEBUG (turned it on)

The error code returned by the function ble_advertising_advdata_update is NRF_SUCCESS

However I do see in the over the air behaviour a delay

The timer is our internally implemented timer which expires every second and from the timer I call to the function 

ble_advertising_advdata_update(&m_advertising, &advdata, NULL); (We do not need any scan response data)

I override simply a data in the ble_advertising_init_t with the new one and call to the ble_advertising_advdata_update

(To my understanding this shall be ok since soft device copies ADV data into internal buffer)

Am I wrong?

[KTM]

Idid some more testing and as soon as mark out the call to the function:

ble_advertising_advdata_update

I am not hitting main. Otherwise I do have a reset(hitting main)

It looks like a crash is within sd_ble_gap_adv_set_configure in the function ble_advertising_advdata_update

What can cause a crash their?

[Karl Ylvisaker]

Hello,

KTM said:

I override simply a data in the ble_advertising_init_t with the new one and call to the ble_advertising_advdata_update

(To my understanding this shall be ok since soft device copies ADV data into internal buffer)

Am I wrong?

No, your understanding here is correct - because the ble_advertising_advdata_update function from SDK v.17 does the copying for you. If you were using an older SDK, such as v.16, you would have had to provide separate buffers for the updated data ( which you might have read other tickets about on the forum ), but this is not the case with SDK v.17.  

KTM said:

Idid some more testing and as soon as mark out the call to the function:

ble_advertising_advdata_update

I am not hitting main. Otherwise I do have a reset(hitting main)

I am sorry, but I do not understand what you are saying here - you said in your previous reply that ble_advertising_advdata_update always returns NRF_SUCCESS, are you now seeing another error code returned?
I suspect that the 1 - 2 second delay between updates is a result of a device reset, which again might be caused by an error cod ebeing returned somewhere.

KTM said:

It looks like a crash is within sd_ble_gap_adv_set_configure in the function ble_advertising_advdata_update

How do you pinpoint this? Using error codes, or using breakpoints?
Please be advised that you may not use breakpoints with a running SoftDevice. The breakpoints will halt the CPU, and the SoftDevice will be unable to perform its timing-critical tasks in time, before you release the CPU again, this will cause the SoftDevice to assert immediately upon leaving the breakpoint.
Are you seeing anything written to your log before the crash? Could you also elaborate what exactly you mean when you say that it looks like it crashes?

Looking forward to resolving this issue together!

Best regards,
Karl

[KTM]

I put a break point in the main on the first line.

I hit it so I assume there was a reset due to some error

This is a way I figure out that there is probably a device reset...

Also within a function ble_advertising_advdata_update I put a point after sd_ble_gap_adv_set_configure call (i.e. on return) and never hit this line so I guess that the reset comes from sd_ble_gap_adv_set_configure

How would you suggest to debug that?