About Read By Type requests from iPhone devices.

RE: About Read By Type requests from iPhone devices.

Susheel Nuguru — Mon, 29 Jan 2024 12:16:56 GMT

I think it is very IOS specific and do not know the implementation details of when they send the Read By Type. But it is possible that the IOS BLE implementation has some timers of activity/inactivity based on which they might send requests like this. This behavior is purely central controlled and I do not think the peripheral can influence this behavior in any meaningful way.

RE: About Read By Type requests from iPhone devices.

hiroiwas — Thu, 25 Jan 2024 09:12:31 GMT

Hello.

I will report what I have learned about the situation.

> Is it possible that the previous Indication event (BLE_GATTC_EVT_HVX) disappears by receiving Read By Type?

Regarding the above, I found out that the Indication does not disappear due to Read By Type, but only appears to disappear due to an abnormality in the data of the Indication frame from the iPhone.

There seems to be enough time between the Indication frame and the Read By Type that there is no relationship.

Regarding Read By Type, it seems that iOS will send it if there is space in BLE, but if you know the conditions, please let me know.

Best regards.

RE: About Read By Type requests from iPhone devices.

hiroiwas — Tue, 23 Jan 2024 08:18:32 GMT

Hello.

> Is it possible to tell me which iphone and which IOS version you see this issue with?

Depending on the thing, there are some patterns in which Read By Type does not occur, but the phenomenon occurs with the following combinations.

iPhoneXR - iOS13.6.1, iOS15.6.1
iPhoneSE2 - iOS14.4

With iPhoneXR, the phenomenon may or may not occur.

The following combination did not cause any problems:

iPhoneX - iOS16.0
iPhoneXS - iOS15.6.1

I hope this information helps you understand something.

Also, please respond to the following inquiries that have already been posted.

Is it possible that the previous Indication event (BLE_GATTC_EVT_HVX) disappears by receiving Read By Type?

Best regards.

RE: About Read By Type requests from iPhone devices.

Susheel Nuguru — Tue, 23 Jan 2024 07:47:19 GMT

[quote user="hiroiwas"]If you insert Read By Type during communication, there is a high probability that it will time out, but do you know why iOS inserts Read By Type?[/quote]

We know that there was an issue 5-10 years ago on Qualcomm chips with BLE having a bug in the stack which they fixed later. So if you are having an old IOS on older phone, maybe you can test this with newer phones.

Is it possible to tell me which iphone and which IOS version you see this issue with? Also can you give me your peripheral project so that I can try to understand more on this issue by testing it at our end?

RE: About Read By Type requests from iPhone devices.

hiroiwas — Mon, 22 Jan 2024 01:28:46 GMT

Hello again.

This is additional information.

Regarding the Indication just before Read By Type, in AirLog, Confirn is performed from the Nordic app side, but it seems that it is not received in the BLE debug log.

This seems to be the direct cause of the timeout, but is it possible that the previous Indication event (BLE_GATTC_EVT_HVX) disappears by receiving Read By Type?

Best regards.

RE: About Read By Type requests from iPhone devices.

hiroiwas — Mon, 22 Jan 2024 00:54:50 GMT

Susheel Nuguru, thank you for your reply.

The device uses nRF52840 and is using s140 v7.3.0.
These are as tagged.

Additionally, LESC is not used and peer_manager is disabled.

This is to speed up the connection, and security is separately ensured through the advertise frame and unique authentication after connection.

> Why is your app not responding to the read request?

It is the iOS app that is not responding.

In the case presented, after the last Indication is sent from the iOS app,
When Read By Transaction is inserted, a timeout (2s) occurs until the next communication in the application management and the connection is disconnected.

If you insert Read By Type during communication, there is a high probability that it will time out, but do you know why iOS inserts Read By Type?

Best regards.

RE: About Read By Type requests from iPhone devices.

Susheel Nuguru — Fri, 19 Jan 2024 13:22:05 GMT

Which SDK are you using on the nRF device and which nRF device is it? nRF52840 as selected in your tags?
Have you enabled LE secure connections?

[quote user=""]Since the communication sequence manages the elapsed time between communications, so this unintended Discovery request causes a timeout.[/quote]

Why is your app not responding to the read request? Have you enabled authorization for the read for this characteristic and have not implemented to respond to the authorize_request?