2118582_en-US

Yes

OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

Issue Summary

We are encountering a failure during Matter multi-admin commissioning using OTBR with the JN5189 RCP. The primary commissioning using the CHIPTool Android APK completes successfully. However, the secondary commissioning using the CHIP Tool CLI fails.

During this process, the otbr-agent logs indicate repeated timeouts when communicating with the RCP, which causes the agent to become unresponsive. The only way to recover is by manually resetting the agent or replugging the RCP.

Setup Details

Component: Version / Description
-----------------------------|--------------------------------------------------------
Primary Commissioner : CHIPTool Android APK
Secondary Commissioner : CHIP Tool CLI (Linux)
Thread Device : Nanoleaf A27 Bulb
RCP Platform : NXP JN5189 over UART
RCP Firmware Commit: dfbe12280af4a87cb9ae0c0c1d90d71de3372d82 (from ot-nxp)
OTBR Platform: Ubuntu 22.04 (x86_64)
Kernel Version: Linux 6.8.0-60-generic ##63~22.04.1-Ubuntu SMP PREEMPT_DYNAMI
OTBR Commit: b8bab1babcb040251b51a69ccb4008fb4b9e2d3f
CHIP Tool CLI Commit: 9af93fd3e9eab4315e1097b19112ebac01d1ad94

Steps to Reproduce

Boot the OTBR with the JN5189 RCP connected and initialized.
Perform primary commissioning using the CHIPTool Android APK (successful).
Use the APK to open a multi-admin commissioning window.
Attempt secondary commissioning using the CHIP Tool CLI.
Observe otbr-agent behavior and log output.

Re: OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

Hi Luis,

1) I’ve tried using a baud rate of "1000000," but I’m still encountering a framing error during communication.

I’ve tested with both UART_DRIVER and SERIAL_MGR. Between the two, which would you recommend as the more reliable and preferred option?

To debug further, I enabled logs and checked the USART FIFO Overflow Register values. I noticed that the RXERR bit is being set in FIFOSTAT.

For reference, USART0 is clocked at 32 MHz (sourced from XTAL), and the main clock is running at 48 MHz.

BR,
Vikash

Re: OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

Hello Vikash

The baud rate will depend on the one the host stablish. Just as an advice maybe you could try "1000000"; as for reference that baud rate is the default in an example for K32W.

The Software flow control is supported in JN5189 using USART0 and USART1, however the Hardware flow control is more reliable and doesn’t interfere with data, The decision would be up to every customer. Described in Chapter 23.6.5.2 UM11138

Best Regards

Luis

Re: OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

Hi Luis,

Thanks for your response.

I've tested the setup using a Raspberry Pi 4B with an nRF52840 DK and didn't encounter any RCP TX timeouts or resets in that configuration. This leads me to believe the issue is likely related to the RCP image or UART configuration on the JN5189.

In my final hardware setup, RTS/CTS hardware flow control is not supported, so I'm limited to UART without flow control. Given this constraint:

1) What is the recommended UART baud rate for the JN5189 RCP when hardware flow control is not available?

2) Are there any buffer sizes, timing parameters, or driver-level settings that should be adjusted to reduce the risk of data loss?

3) Is software flow control (XON/XOFF) supported or recommended in this scenario?

Best Regards
Vikash

Re: OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

Hello,

The UART clock impact timing accuracy, if the UART clock is unstable, it can cause loss of synchronization between the host and RCP.

Match baud rates carefully between devices and test for tolerance margins, you could try a lower baud rate.

Or as other option; Instead of using the FRO32K, you could switch to the XTAL32K oscillator, which offers better clock frequency accuracy; You can find more information about it in the User Manual [ UM11138] Chapter 4.4.4 UM11138

Best Regards

Luis

Re: OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

Hello,

Thanks for your reply.

I have a few questions and observations:
Does the UART clock source significantly impact timing accuracy and data sampling?

Currently, the system is configured to use FRO32K as the clock source.

Observation:
When testing communication with the host:

At 1 Mbps, I get around 3/10 successful attempts.

At 115200, communication rarely succeeds.

It seems the issue might be related to imprecise UART baud rate generation due to using a low-frequency (32.768 kHz) clock.

Re: OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

Hello,

Sorry for the late response, The JN5189 supports Hardware Flow control in the USART0, you can find more information about it in the User Manual [ UM11138] Chapter 23.6.5.1 UM11138

The baud rate will depend on the one the host stablish.

Best Regards

Luis

Re: OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

Hi Luis,

I've reviewed the logs from both ends and noticed instances of data corruption or loss occurring on the RCP side.

Could you please suggest the ideal UART baud rate for the JN5189 in this specific case?

Re: OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

Hi Luis,

Thank you for your feedback and for sharing the reference link.

We've already placed an order for the i.MX8M platform and are currently waiting for it to arrive. In the meantime, I would like to continue debugging using the existing JN5189 setup.

As part of that, I wanted to confirm whether the JN5189 supports hardware flow control on the UART interface. This will help us assess the communication stability while isolating the issue.

Thanks
Vikash

Re: OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

Hello,

I review the file nxp_vendor_hook.cpp; This file is destined for both JN5189 and K32W061.

Just for testing purposes, I will recommend you use an i.MX8M and try to isolate the issue to the root cause.

This following link redirect to examples running Open Thread Border Router with i.MX for consulting

How to setup OpenThread Border Router and Openther Deamon on the target

Best Regards

Luis

Re: OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

Hi Luis,

Thank you for your prompt response.

I’ve tested the setup on the following two platforms and encountered the same issue on both:
i) Laptop (Ubuntu)
ii) Router (OpenWRT)

1) From my observations during the commissioning process, the Thread end device sends a rapid sequence of messages to the chip-tool commissioner in response to a request. This quick burst of traffic may be causing the RCP to drop some packets, which the OTBR is likely expecting and waiting for2).

2) For the external commissioning, I believe the main constraint is the PSKd, which is why I’ve raised the concern with the Thread group and am currently awaiting their response.

3) Could you also take a look at the following issue?
There is an nxp_vendor_hook.cpp file used when building for the K32W061 platform.
I'm wondering whether a similar file exists for the JN5189 platform or if it's possible to reuse the existing nxp_vendor_hook.cpp for JN5189 by enabling the DOT_NCP_VENDOR_HOOK_SOURCE macro during compilation.

Re: OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

Hello,

Have you tested running OTBR with an MCU/MPU instead of a computer? as the examples and guidelines that NXP support are destined for different Host's testings and have more information about it.

The compilation for the K32W061 could apply to the JN5189, both are very similar.

Also, could you take a look in External Commissioning | OpenThread if this apply to your additional commissioning issue?

Best Regards

Luis

Re: OTBR Agent Timeout with JN5189 RCP During Commissioning in Multi-Admin Mode Due to No Response

There is an nxp_vendor_hook.cpp file, which is used when compiling for the K32W061 platform.

Do we have similar file for JN5189 platform, or Can we reuse it for the JN5189 by including/enabling the

DOT_NCP_VENDOR_HOOK_SOURCE Macro during Compilation?
?