multi-nus peripheral nrf52833

RE: multi-nus peripheral nrf52833

Einar Thorsrud — Wed, 22 Nov 2023 15:19:39 GMT

Hi,

I have not tested on my end, but based on what you describe and your code, I wonder if this is what is happening:

The central have a connection with a perhiperal
The periperal is reset
The central is still connected to the peripheral until supervision timeout, but the peripheral starts advertising
The central, as it is intended for multiple devices, scans even though it is still connected, and sees the old peripheral advertise and attempts to connect. This triggers the error you see (bt_conn_le_create() calls bt_conn_exists_le() and this prints the "" error, and then bt_conn_le_create returns -EINVAL.).

Are you able to verify that bt_conn_le_create() returns -EINVAL when this issue occurs?

If this is the problem, you could either add some logic to avoid connecting to a device you already have a connection (using a similar method as what is used in the stack when you get this error), or you could ignore the -EINVAL return value from bt_conn_le_create(), though that may not be a good idea as there are also other reasons you could get that error code from bt_conn_le_create().

RE: multi-nus peripheral nrf52833

Muhammad Usman — Mon, 20 Nov 2023 15:07:54 GMT

Hi Einar!

Thank you so much for the response!

[quote userid="7377" url="~/f/nordic-q-a/102307/multi-nus-peripheral-nrf52833/456484"]Is it so that you trigger this by resetting the peripheral[/quote]

Yes, you are right. I am trying to simulate that the peripheral is going to sleep mode and then wake up to send the data.

So what is your expert opinion regarding that?

Thanks in advance! For your response!

RE: multi-nus peripheral nrf52833

Einar Thorsrud — Mon, 20 Nov 2023 14:57:21 GMT

Hi Muhammad,

Edvin is OoO so I have inherited this case.

You get "Found valid connection in connected state" so it seems you are trying to re-connect ot a device you are already connected with. So something is seemingly out of sync. Is it so that you trigger this by resetting the peripheral, and that is why you have a lot of disconnects with reason 8 (supervision timeout) here?

RE: multi-nus peripheral nrf52833

Muhammad Usman — Wed, 15 Nov 2023 16:52:57 GMT

Hi Edvin,

Sorry for the very late response!

today I started again from where I left, I attached the log of central. When the central gets stuck and stops scanning any peripheral.Although I reset both the peripherals many times . Here is the log

00:15:16.907,012] <wrn> central_uart: ATT error code: 0x20011C0C
[00:15:35.807,983] <inf> central_uart: Disconnected: E8:2B:FD:17:14:C2 (random) (reason 8)
[00:15:36.953,033] <wrn> central_uart: Connecting failed
[00:15:37.046,234] <inf> central_uart: MTU (0): 23
[00:15:37.046,325] <inf> central_uart: Exchange pending...
[00:15:37.046,356] <inf> central_uart: Connected: E8:2B:FD:17:14:C2 (random)
[00:15:37.047,943] <inf> central_uart: NUS Client module initialized
[00:15:37.159,362] <inf> central_uart: MTU exchange 0 successful (65)
[00:15:37.906,890] <inf> central_uart: Service discovery completed
[00:15:37.910,614] <inf> central_uart: Scanning started
[00:15:37.910,736] <inf> central_uart: Sent to server 0: 0
[00:15:38.106,994] <wrn> central_uart: ATT error code: 0x20011C0C
[00:16:35.850,708] <inf> central_uart: Disconnected: F7:13:07:67:2D:04 (random) (reason 8)
[00:16:40.990,722] <wrn> central_uart: Connecting failed
[00:16:41.082,824] <inf> central_uart: MTU (1): 23
[00:16:41.082,885] <inf> central_uart: Exchange pending...
[00:16:41.082,946] <inf> central_uart: Connected: F7:13:07:67:2D:04 (random)
[00:16:41.084,564] <inf> central_uart: NUS Client module initialized
[00:16:41.216,796] <inf> central_uart: MTU exchange 1 successful (65)
[00:16:41.965,148] <inf> central_uart: Service discovery completed
[00:16:41.968,811] <inf> central_uart: Scanning started
[00:16:41.968,963] <inf> central_uart: Sent to server 1: 1
[00:16:42.164,489] <wrn> central_uart: ATT error code: 0x20011BC8
[00:17:11.365,570] <inf> central_uart: Disconnected: F7:13:07:67:2D:04 (random) (reason 8)
[00:17:14.811,920] <wrn> central_uart: Connecting failed
[00:17:14.905,944] <inf> central_uart: MTU (1): 23
[00:17:14.906,036] <inf> central_uart: Exchange pending...
[00:17:14.906,066] <inf> central_uart: Connected: F7:13:07:67:2D:04 (random)
[00:17:14.907,653] <inf> central_uart: NUS Client module initialized
[00:17:15.016,815] <inf> central_uart: MTU exchange 1 successful (65)
[00:17:15.864,471] <inf> central_uart: Service discovery completed
[00:17:15.868,164] <inf> central_uart: Scanning started
[00:17:15.868,347] <inf> central_uart: Sent to server 1: 1
[00:17:16.164,550] <wrn> central_uart: ATT error code: 0x20011BC8
[00:17:19.208,007] <inf> central_uart: Disconnected: E8:2B:FD:17:14:C2 (random) (reason 8)
[00:17:19.244,537] <wrn> central_uart: Connecting failed
[00:17:19.340,240] <inf> central_uart: MTU (0): 23
[00:17:19.340,362] <inf> central_uart: Exchange pending...
[00:17:19.340,362] <inf> central_uart: Connected: E8:2B:FD:17:14:C2 (random)
[00:17:19.342,041] <inf> central_uart: NUS Client module initialized
[00:17:19.474,395] <inf> central_uart: MTU exchange 0 successful (65)
[00:17:20.221,954] <inf> central_uart: Service discovery completed
[00:17:20.225,677] <inf> central_uart: Scanning started
[00:17:20.225,799] <inf> central_uart: Sent to server 0: 0
[00:17:20.421,997] <wrn> central_uart: ATT error code: 0x20011C0C
[00:19:17.665,618] <inf> central_uart: Disconnected: F7:13:07:67:2D:04 (random) (reason 8)
[00:19:20.555,419] <wrn> central_uart: Connecting failed
[00:19:20.647,644] <inf> central_uart: MTU (1): 23
[00:19:20.647,735] <inf> central_uart: Exchange pending...
[00:19:20.647,766] <inf> central_uart: Connected: F7:13:07:67:2D:04 (random)
[00:19:20.649,353] <inf> central_uart: NUS Client module initialized
[00:19:20.831,756] <inf> central_uart: MTU exchange 1 successful (65)
[00:19:21.679,443] <inf> central_uart: Service discovery completed
[00:19:21.683,135] <inf> central_uart: Scanning started
[00:19:21.683,288] <inf> central_uart: Sent to server 1: 1
[00:19:21.879,425] <wrn> central_uart: ATT error code: 0x20011BC8
[00:19:31.522,979] <inf> central_uart: Disconnected: E8:2B:FD:17:14:C2 (random) (reason 8)
[00:19:32.566,619] <wrn> central_uart: Connecting failed
[00:19:32.665,283] <inf> central_uart: MTU (0): 23
[00:19:32.665,405] <inf> central_uart: Exchange pending...
[00:19:32.665,435] <inf> central_uart: Connected: E8:2B:FD:17:14:C2 (random)
[00:19:32.666,992] <inf> central_uart: NUS Client module initialized
[00:19:32.789,398] <inf> central_uart: MTU exchange 0 successful (65)
[00:19:33.536,956] <inf> central_uart: Service discovery completed
[00:19:33.540,618] <inf> central_uart: Scanning started
[00:19:33.540,740] <inf> central_uart: Sent to server 0: 0
[00:19:33.736,999] <wrn> central_uart: ATT error code: 0x20011C0C
[00:19:50.238,067] <inf> central_uart: Disconnected: E8:2B:FD:17:14:C2 (random) (reason 8)
[00:19:50.787,261] <wrn> central_uart: Connecting failed
[00:19:50.879,577] <inf> central_uart: MTU (0): 23
[00:19:50.879,669] <inf> central_uart: Exchange pending...
[00:19:50.879,699] <inf> central_uart: Connected: E8:2B:FD:17:14:C2 (random)
[00:19:50.881,256] <inf> central_uart: NUS Client module initialized
[00:19:50.989,410] <inf> central_uart: MTU exchange 0 successful (65)
[00:19:51.736,938] <inf> central_uart: Service discovery completed
[00:19:51.740,631] <inf> central_uart: Scanning started
[00:19:51.740,753] <inf> central_uart: Sent to server 0: 0
[00:19:51.936,981] <wrn> central_uart: ATT error code: 0x20011C0C
[00:19:56.497,711] <wrn> bt_conn: Found valid connection in connected state
[00:19:56.507,873] <wrn> bt_conn: Found valid connection in connected state
[00:19:56.507,873] <wrn> central_uart: Connecting failed
[00:19:59.988,037] <inf> central_uart: Disconnected: E8:2B:FD:17:14:C2 (random) (reason 8)
[00:20:25.330,444] <inf> central_uart: Disconnected: F7:13:07:67:2D:04 (random) (reason 8)

if you see

[00:19:56.497,711] <wrn> bt_conn: Found valid connection in connected state
[00:19:56.507,873] <wrn> bt_conn: Found valid connection in connected state
[00:19:56.507,873] <wrn> central_uart: Connecting failed
[00:19:59.988,037] <inf> central_uart: Disconnected: E8:2B:FD:17:14:C2 (random) (reason 8)
[00:20:25.330,444] <inf> central_uart: Disconnected: F7:13:07:67:2D:04 (random) (reason 8)

What I understand is, that Central has info that, peripherals are already connected but in actual they are not.

This happens when we disconnect and connect the peripheral many times continuously. Like in 1 min 4-6 times.

These are the last lines where Central gets stuck. After resetting the central it starts scanning again. Can you please guide me regarding that?

Thanks & Regards,

Muhammad Usman

RE: multi-nus peripheral nrf52833

Edvin — Mon, 07 Aug 2023 07:45:40 GMT

Hello,

Regarding 1: So you are trying to enable notifications (bt_gatt_subscribe) after the connection has terminated? Are you enabling notifications all the time? It is something you only should need to do once after the connection is established.

Regarding 3: Is bt_nus_send() called but is blocking? Or is it not called when it "stops responding"? Try to add some logs before and after the call to bt_nus_send(), to see whether it is stuck in there.

Best regards,

Edvin

RE: multi-nus peripheral nrf52833

Muhammad Usman — Fri, 04 Aug 2023 14:49:06 GMT

Hi Edvin!

Thank you for your previous response! results of my testing are

1)Sometimes, when I reset the peripheral then the central Resets itself as well

Connection pending<CR><LF>
<EOT><SOH><ACK><ETX><ETX>ªþ<ETB><SYN>ªþASSERTION FAIL [conn] @ WEST_TOPDIR/zephyr/subsys/bluetooth/host/gatt.c:4738<CR><LF>
<HT> invalid parameters<CR><LF>
<CR><LF>
*** Booting Zephyr OS build v3.0.99-ncs1-1 ***<CR><LF>
Starting Bluetooth Central UART example<CR><LF>
Filters matched. Address: F7:13:07:67:2D:04 (random) connectable: yes<CR><LF>
Connection pending<CR><LF>

2)When i send multiple messages (25 ) from peripheral to central then central hangs to solve this i added this line

struct uart_data_t *buf = k_fifo_get(&fifo_uart_rx_data,

K_FOREVER);

multi_nus_send(buf);

k_free(buf); // this line added in main

Now this issue is not occurring again.

3)[quote userid="26071" url="~/f/nordic-q-a/102307/multi-nus-peripheral-nrf52833/439681"]Remember to check what bt_nus_send() returns. It may give a hint to what the issue may be. Does it return 0 or something else?[/quote]

error1=bt_nus_send(NULL,raw_adv_data,sizeof(raw_adv_data)-20);

if(error1<0) {

printf("Failed to send data over BLE connection, error is for DK is ... %d", error1);

// LOG_WRN("Failed to set DSR, ret code %d", error1);

}

Peripheral on reset starts sending data again but not displayed the above message on no communication. Means the peripheral close the connection.

Any more suggestions?

Thanks & regards,

Muhammad Usman

RE: multi-nus peripheral nrf52833

Muhammad Usman — Thu, 03 Aug 2023 17:48:26 GMT

thank you again! i will check and update on this soon!

RE: multi-nus peripheral nrf52833

Edvin — Thu, 03 Aug 2023 11:26:13 GMT

Remember to check what bt_nus_send() returns. It may give a hint to what the issue may be. Does it return 0 or something else?

RE: multi-nus peripheral nrf52833

Muhammad Usman — Thu, 03 Aug 2023 11:03:48 GMT

Hi Edvin,

Thank you for the response!

[quote userid="26071" url="~/f/nordic-q-a/102307/multi-nus-peripheral-nrf52833/439204"]Can you please upload both the central and peripheral applications that you are using?[/quote]

Peripherals Side FWH: ncs v2.3.0

devzone.nordicsemi.com/.../Multicon_5F00_inter_5F00_Reg_5F00_peri_2D00_main_5F00_Luis_5F00_V1.zip

Central side FWH: ncs v2.0.2

devzone.nordicsemi.com/.../central_5F00_uart_5F00_con_5F00_202.zip

[quote userid="26071" url="~/f/nordic-q-a/102307/multi-nus-peripheral-nrf52833/439204"]When this happens, do you see a disconnected event either in the central or the peripheral? You say that they stop communicating. What usually triggers the communication? Is it a timer that times out? is it a button press? Is it a UART command? Are you using bt_nus_send() to communicate? Is that still being called? What does it return?[/quote]

I am using the timers to communicate after every 5 seconds, yes I am using the bt_nus_send() to communicate with the central. No, I didn't see any disconnected event either in the central or the peripheral. But I will check it again to confirm your answer.

Thanks & Regards,

Muhammad Usman

RE: multi-nus peripheral nrf52833

Edvin — Tue, 01 Aug 2023 09:20:09 GMT

Hello,

We are trying to even out the workload after the summer holidays, so Simon asked if I could take a look at this ticket.

Can you please upload both the central and peripheral applications that you are using?

When you reset both the peripheral devices, and they are not reconnected (2 out of 10 times), do you see the disconnected event in the central device? (It looks like it should print it in the log).

[quote user=""]3)Sometimes 3 out of 10 times, the custom board (nrf52833) stops communication with the central automatically so need to reset it. But it never happened with peripheral (DK).[/quote]

When this happens, do you see a disconnected event either in the central or the peripheral? You say that they stop communicating. What usually triggers the communication? Is it a timer that times out? is it a button press? Is it a UART command? Are you using bt_nus_send() to communicate? Is that still being called? What does it return?

[quote user=""]4)Is there any filter on the Mac address? .Because the Custom board address starts with F7:13 and DK from E2:2B.malfuncationing behaviour observed with central as mentioned in point # 3 [/quote]

What do you mean by filtering on Mac address? During scanning/connection, or while being connected?

It is possible to filter on Mac addresses, but it is not really that common, because it would require a designated application for all devices (in mass production). Usually you would filter on advertising data (advertised UUID or an advertising name). When you are connected to multiple devices, you can use the conn pointers from the connected event. I would recommend storing these as long as the connection remains. This means setting it in the connected event, and setting it to NULL in the disconnected event. You can store an array of static struct bt_conn*, much like the central_uart from the ncs\nrf\samples\bluetooth\central_uart does (although it doesn't store it as an array, as it only handles one connection). Look at how this sample does that, and try to implement something similar.

Best regards,

Edvin

RE: multi-nus peripheral nrf52833

Muhammad Usman — Sat, 29 Jul 2023 15:54:51 GMT

Hi Simonr

Thank you for the response! Please take your time, no issue.

My setup was that , 1st DK (nrf52833) as Central and 2nd DK (nrf52833) as Peripheral # 1 and the custom board (nrf52833) as

Peripheral # 2.

Today I observed the following:

1)RSSI difference between both the peripherals. DK RSSI is -55dbm and custom -85dbm roundabout.

E8:2B is DK

F7:13 is a custom board

[quote userid="75734" url="~/f/nordic-q-a/102307/multi-nus-peripheral-nrf52833/438751"]Do the peripherals start advertising again automatically upon a disconnected event? It might be that they're not since you need to restart the peripherals to see them scanning again.[/quote]

2) yes peripherals start advertising again automatically and advertised after every 10-20 seconds. But no connection from central

[quote userid="75734" url="~/f/nordic-q-a/102307/multi-nus-peripheral-nrf52833/438751"]It could also be that the central just doesn't time out the connection right away if the peripherals disconnect without sending a disconnect event to the central.[/quote]

In that case, will the peripherals start advertising again? How can we confirm that point?

[quote userid="75734" url="~/f/nordic-q-a/102307/multi-nus-peripheral-nrf52833/438751"]Then it will take approximately the conn_sup_timeot before the connection times out, and I presume before the central starts scanning for advertising devices again.[/quote]

struct bt_le_conn_param m_conn_param={

.interval_min=120,

.interval_max=220,

.timeout=100,

};

is that the connection time out you are talking about in 100ms, am I right?

4)I waited for about 20 mins, peripheral started advertising continuously after every 10-20 secs but no connection. Although meanwhile, the central was communicating with the 2nd peripheral(DK) . Central only connected when I reset the central

5)When I reset the central the peripherals not advertising, so need to reset the peripherals as well.

Filters matched. Address: E8:2B:FD:17:14:C2 (random) connectable: yes<CR><LF>
Connection pending<CR><LF>
Filters matched. Address: F7:13:07:67:2D:04 (random) connectable: yes<CR><LF>
Stop LE scan failed (err -120)<CR><LF>
Create conn failed (err -120)<CR><LF>
Scanning failed to start (err -5)<CR><LF>

6) Sometimes it works perfectly! and 6 out of 10 tests it works as I explained above.

[quote userid="75734" url="~/f/nordic-q-a/102307/multi-nus-peripheral-nrf52833/438751"]Both DKs and custom boards are nRF52833 devices, correct?[/quote]

Yes, correct!

[quote userid="75734" url="~/f/nordic-q-a/102307/multi-nus-peripheral-nrf52833/438751"] What revision of the DKs do you have,[/quote]

First is 1.0.0 2019

2nd is 1.0.0 2020

[quote userid="75734" url="~/f/nordic-q-a/102307/multi-nus-peripheral-nrf52833/438751"]what revisions of the SoCs on the custom boards are running?[/quote]

nRF52833-QDAA-R

Thanks & Regards,

Muhammad Usman

RE: multi-nus peripheral nrf52833

Simonr — Fri, 28 Jul 2023 12:49:15 GMT

Due to the summer vacation period we are currently understaffed, so delayed replies must be expected. I am sorry about any inconvenience this might cause.

A few thoughts as to what this could be.

Do the peripherals start advertising again automatically upon a disconnected event? It might be that they're not since you need to restart the peripherals to see them scanning again.
It could also be that the central just doesn't time out the connection right away if the peripherals disconnect without sending a disconnect event to the central. Then it will take approximately the conn_sup_timeot before the connection times out, and I presume before the central starts scanning for advertising devices again.

4. There should not be a filter on MAC addresses in this sample project. Both DKs and custom boards are nRF52833 devices, correct? What revision of the DKs do you have, and what revisions of the SoCs on the custom boards are running?

Best regards,

Simon