nRF5 SDK v17.0.2: RTT output does not work with specified SES version

[awneil]

After downloading nRF5 SDK v17.0.2, I checked the Release Notes - and they state SES v4.50 has "been used for testing".

So I downloaded & installed SES v4.50

The HID Keyboard example builds & works fine, but RTT logs display in the SES Debug Terminal does not work - it just shows blank lines.

This is a long-standing known issue:

https://devzone.nordicsemi.com/f/nordic-q-a/45985/nrf_log-not-working-on-segger-embedded-studio/181804#181804 - over 2 years ago!

Surely, this should have been fixed in the example by now?

As stated in that thread, the fix is to disable NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED

[ovrebekk]

Hi Andrew

I agree this is a well know issue that should have been picked up by now. 

I will follow this up with the developers and try to get it patched in the next SDK release. 

Apparently the options are to either disable the NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED flag, which might cause line break issues in some terminals, or to add code to handle the \r\r\n issue, which would add some runtime overhead. 

I will get back to you later in the week with an update. 

Best regards
Torbjørn

[awneil]

I think you should blame Segger - whoever thought it would be a good idea to interpret 2 consecutive CRs as "erase the current line"?

https://devzone.nordicsemi.com/f/nordic-q-a/45985/nrf_log-not-working-on-segger-embedded-studio/182742#182742

SEGGER - Johannes SEGGER - Paul Curtis SEGGER - Alex Gruener

[ovrebekk]

Hi Andrew

Fair point, in most terminals there would be no difference if you send CR once or twice...

The developers investigated this, and found that the runtime overhead of handling the \r\r\n was very minimal. They patched the issue internally, and it should be included in the next SDK release. 

If anyone wants to test it out before that I have included the patched files here. Just replace the original files in the \nRF5_SDK_17.0.2_d674dde\external\fprintf folder with these:

6472.fprintf_patched.zip

Best regards
Torbjørn

[awneil]

ovrebekk said:

in most terminals there would be no difference if you send CR once or twice

Indeed.

And, in fact, in Segger's own standalone RTT viewer there is no difference - it is only within SES they introduced this bizarre handling of a double-CR.

ovrebekk said:

I have included the patched files here

Thanks - will give it a go.

Are you also in touch with Segger to have them verify the solution?

[ovrebekk]

Hi Andrew

I will check in with Segger and see if they have some input on this. 

Best regards
Torbjørn