Galaxy Tab A8 fails to connect properly, while Galaxy Phone S10 works fine

[tellg]

Galaxy Tab A8 connects, but then disconnects after a burst of approx 600 "Central_0x2a208f55 Peripheral_0x2a208f55 ATT 37 Sent Read By Group Type Request, Primary Service, Handles: 0x0001..0xffff"

Galaxy S10 works fine

Bot are running the same mobile app.

I have attached 2 Wireshark capture files, one for Samsung Galaxy Tab A8, the other for Samsung Galaxy S10 

We use ncs 2.6.1 on our nRF52840 hardware

SamsungS10.pcapngsamsungA8.pcapng

[Simonr]

Hi

At least in the nRF Connect for Android app you can set the supported PHYs in the settings of the app (Settings -> Scanner -> Physical layer) to 1MBPS if you'd like.

Best regards,

Simon

[tellg]

That does not help, as we anyhow end up in 2MBPS as soon as connection is done

I also tried this macro, but still end up in 2MBPS  

Fullscreen SetPreferredPhy_1M.xml Download

<!-- 
	Transmitter and Receiver PHY attributes accept the fofflowing values and logical OR operator ('|'):
    - LE_1M - legacy LE 1M PHY (default), 
    - LE_2M - double speed, Bluetooth 5 feature,
    - LE_CODED - long range, Bluetooth 5 feature.

    The options for the Transmitter LE Coded PHY are:
    - NO_PREFERRED - No preferred coding when transmitting on the LE Coded PHY (default),
    - S2 - Prefer the S=2 coding to be used when transmitting on the LE Coded PHY,
    - S8 - Prefer the S=8 coding to be used when transmitting on the LE Coded PHY. 

    Example: <set-preferred-phy tx="LE_2M | LE_CODED" rx="LE_1M" />
 -->
<macro name="SetPreferredPhy_1M" icon="PLAY">
    <set-preferred-phy tx="LE_1M" rx="LE_1M" />
</macro>

nRFConnect log: 

Fullscreen 3051.Log_2024-10-07_11_14_25.txt Download

nRF Connect, 2024-10-07
99 (DB:22:BE:33:59:30)
D	11:14:09.205	gatt.close()
D	11:14:09.209	wait(200)
V	11:14:09.410	Connecting to DB:22:BE:33:59:30...
D	11:14:09.411	gatt = device.connectGatt(autoConnect = false, TRANSPORT_LE, preferred PHY = LE 1M)
D	11:14:10.240	[Callback] Connection state changed with status: 0 and new state: CONNECTED (2)
I	11:14:10.240	Connected to DB:22:BE:33:59:30
D	11:14:10.246	[Broadcast] Action received: android.bluetooth.device.action.ACL_CONNECTED
V	11:14:10.252	Discovering services...
D	11:14:10.252	gatt.discoverServices()
D	11:14:10.361	[Callback] Services discovered with status: 0
I	11:14:10.361	Services discovered
V	11:14:10.368	Generic Attribute (0x1801)
- Service Changed [I] (0x2A05)
   Client Characteristic Configuration (0x2902)
- Client Supported Features [R W] (0x2B29)
- Database Hash [R] (0x2B2A)
Generic Access (0x1800)
- Device Name [R W] (0x2A00)
- Appearance [R] (0x2A01)
- Peripheral Preferred Connection Parameters [R] (0x2A04)
Battery Service (0x180F)
- Battery Level [N R] (0x2A19)
   Client Characteristic Configuration (0x2902)
Device Information (0x180A)
- Model Number String [R] (0x2A24)
- Manufacturer Name String [R] (0x2A29)
- Serial Number String [R] (0x2A25)
- Firmware Revision String [R] (0x2A26)
- Hardware Revision String [R] (0x2A27)
XXXX Service (000001b0-d746-4092-84e7-dad34863fe4a)
- Status [N R] (000001b2-d746-4092-84e7-dad34863fe4a)
   Client Characteristic Configuration (0x2902)
- AAAA [W] (000001b1-d746-4092-84e7-dad34863fe4a)
YYYY Service (000001e0-d746-4092-84e7-dad34863fe4a)
- BBBB [R W] (000001e1-d746-4092-84e7-dad34863fe4a)
- Unknown Characteristic [R] (000001ec-d746-4092-84e7-dad34863fe4a)
Nordic UART Service (6e400001-b5a3-f393-e0a9-e50e24dcca9e)
- TX Characteristic [N] (6e400003-b5a3-f393-e0a9-e50e24dcca9e)
   Client Characteristic Configuration (0x2902)
- RX Characteristic [W WNR] (6e400002-b5a3-f393-e0a9-e50e24dcca9e)
SMP Service (8d53dc1d-1db7-4cd3-868b-8a527460aa84)
- SMP Characteristic [N WNR] (da2e7828-fbce-4e01-ae9e-261174997c48)
   Client Characteristic Configuration (0x2902)
D	11:14:10.369	gatt.setCharacteristicNotification(00002a05-0000-1000-8000-00805f9b34fb, true)
D	11:14:10.371	gatt.setCharacteristicNotification(00002a19-0000-1000-8000-00805f9b34fb, true)
D	11:14:10.373	gatt.setCharacteristicNotification(000001b2-d746-4092-84e7-dad34863fe4a, true)
D	11:14:10.375	gatt.setCharacteristicNotification(6e400003-b5a3-f393-e0a9-e50e24dcca9e, true)
I	11:14:10.628	PHY updated (TX: LE 2M, RX: LE 2M)
V	11:14:14.558	Requesting preferred PHYs...
D	11:14:14.558	gatt.setPreferredPhy(LE 1M, LE 1M, coding option = No preferred)
I	11:14:14.723	PHY updated (TX: LE 2M, RX: LE 2M)
I	11:14:15.127	Connection parameters updated (interval: 37.5ms, latency: 0, timeout: 420ms)

Seems like setPreferredPhy is just a recommendation, and depends on local and remote controllers behaviour

https://developer.android.com/reference/android/bluetooth/BluetoothGatt#setPreferredPhy(int,%20int,%20int)