Upgrading to newer SDK broke RTT processing of backspace character.

[SteveKranz]

Problem: Upgrading to newer SDK broke RTT processing of backspace character.

Details: We had been using RTT with the v2.4.1 SDK (for our nRF52840 development) and yesterday we upgraded to v2.5.0 and now find that RTT will no longer process the backspace character. You can type into the RTT terminal but backspace no longer has any effect. The only change we made was the SDK upgrade. Our application uses a pretty simple prj.conf file and in it we have the following lines that we believed were all that was necessary to have a working RTT (and in fact it did seem adequate with SDK v2.4.1). Any ideas?

Note: prj.conf pertinent lines:
# ------- Debug instrumentation via RTT.
CONFIG_CONSOLE=y
CONFIG_RTT_CONSOLE=y
CONFIG_LOG=y
CONFIG_LOG_BACKEND_RTT=y
CONFIG_SHELL=y
CONFIG_SHELL_BACKENDS=y
CONFIG_SHELL_BACKEND_RTT=y
CONFIG_LOG_BACKEND_RTT_BUFFER=1
CONFIG_USE_SEGGER_RTT=y
CONFIG_SHELL_PROMPT_RTT="$ "
# -------

Any help would be appreciated. Thanks in advance.

Steve K.
PuzL Labs, LLC

[Raoul]

Hi Steve,

Which RTT viewer are you using?

I tried to reproduce this using the shell_module sample with the prj_minimal_rtt.conf configuration, using NCS v.2.4.0 just to check the "before" behavior.

Using the Segger RTT viewer, I had no issues, but when I used the RTT Viewer included with our VS Code Extension, I found that using backspace will not be reflected in the local echo in the extension. Meaning, backspaces don't visually do anything but in the background they are actually registering on the nRF52840. (if I type "asdf", then backspace 4 times and type "help", it clearly only sends the help command". You could try it.).

Could this be what you are experiencing? If so, this might be an issue with the extension (since I'm seeing this on v2.4.0 already). Perhaps it has been updated recently.

If you are experiencing something different - Could you try to create a reproduction of the issue based on a modified sample, instead of your own application? That would make it easier for the developers to investigate.

Best regards,

Raoul

[SteveKranz]

Hi Raoul, thank you for your response. You asked which RTT viewer I am using. Yes, I am using the RTT Viewer included with the VS Code Extension, and your backspace description does match my results (I went back and tried it again). In other words, as you say: "I found that using backspace will not be reflected in the local echo in the extension. Meaning, backspaces don't visually do anything but in the background they are actually registering on the nRF52840."

I believe you were suggesting the problem resides with the VSCode Nordic Extension as you see good results when using an alternate RTT viewer. Thanks again for narrowing in on this. I am curious how I would know that a corrected VSCode Nordic Extension has become available? Will the VSCode extension panel show me when a new version is available? Probably. I am fairly new to VSCode/Nordic. Thanks in advance.

Steve K. , PuzL Labs, LLC

[SteveKranz]

Hi Raoul,

I'd like to mention that I also am having the same issue even though I have the nRF Terminal set to the recommended Character mode.

I'm using the 2.5.2 ToolChain/SDK, MacBook M1, Sonoma 14.2.1 MacOS, VSCode 1.81.0.

Thanks, Steve K.

[Maria Gilje]

Hello Steve and mrd,

I have reproduced this as well and contacted the developers for more assistance.

Please share which version of VS Code extension you have installed.

Best regards,

Maria

[SteveKranz]

I have the latest release of VS Code extension. Glad to hear that your are able to reproduce the issue.

Thanks!, Steve K.

[mrd]

Hi Maria, I am also on the latest: v2024.2.214

[Maria Gilje]

Thank you for your responses.

I got some feedback from the extension team, and it is not an extension issue, but a change with NCS v2.5.0. I have started to look into what specifically this could be and I will involve the relevant developers.

In the mean time, please use the SEGGER RTT Viewer instead of the RTT terminal in VS Code. Backspacing works as expected in the input field.

I will update this ticket with any news regarding the lack of visual backspace.

Best regards,

Maria

[SteveKranz]

Hi Maria,

Just a reminder, however:
The Segger RTT viewer by default is set for Input->Sending...->"Send on Input" and this resulted in the same behavior as the VSCode exetension But if you switch the Segger RTT viewer to Input->Sending...->"Send on Enter" then you get what is desired.

Thanks,
Steve

[Maria Gilje]

Hello Steve and mrd,

Our developers has verified that the backspacing works with nRF Terminal v2024.9.14 and nRF Connect SDK v2.8.0.

Whenever convenient, please check if it works for you.

Best regards,

Maria