Can't get RTT working on L15 using J-Link Plus.

[Calvin T]

I can flash the chip. I can run the debugger. I can go to the connected devices, select the device, go to the little "plug" symbol on the RTT, and select it. That brings up a window asking me to select a device. I select the j-tag device, and then select the processor. It appears to work, but then when I try to run the debugger, I get this:

[00:00:00.390,843] <inf> eeprom_drvr: EEPROM initialized
[00:00:00.391,242] <inf> rgb_led_drvr: LED driver initialized
*** Booting nRF Connect SDK v3.0.0-3bfc46578e42 ***
*** Using Zephyr OS v4.0.99-3e0ce7636fa6 ***
[00:00:00.391,493] <inf> sp_log: Initializing Device: smartpac_l15_eval

[00:00:00.393,514] <inf> fs_nvs: 2 Sectors of 4096 bytes
[00:00:00.393,521] <inf> fs_nvs: alloc wra: 0, f10
[00:00:00.393,525] <inf> fs_nvs: data wra: 0, 120
[00:00:00.393,614] <inf> bt_sdc_hci_driver: SoftDevice Controller build revision:
c7 53 7d bc 06 12 f7 c0 b3 3a 3e 28 8e 56 1e d7 |.S}..... .:>(.V..
a0 be 95 b0 |....
[00:00:00.395,368] <inf> bt_hci_core: HW Platform: Nordic Semiconductor (0x0002)
[00:00:00.395,386] <inf> bt_hci_core: HW Variant: nRF54Lx (0x0005)
0m
m

And then nothing else. A colleague has repeated the process, and the RTT works fine on their system. I'm running nrfutil-device 2.11.0. The nRF connect toolchain and SDK are both 3.0.

Any thoughts?

[Simonr]

Hi

Okay, nothing obvious in the differences on the systems. What sample project are you trying to run, and can you confirm the CONFIG_LOG_BACKEND_RTT is set to Y in your project? It should default to Y if CONFIG_SHELL_LOG_BACKEND is not enabled, and if the following dependencies are set correctly:

CONFIG_USE_SEGGER_RTT && !CONFIG_LOG_FRONTEND_ONLY && !CONFIG_LOG_MODE_MINIMAL && CONFIG_LOG

Did your colleague also use the same exact project and setup to get it up and running? And are you using the same nRF54L15 DKs? If not, what version numbering is there on the DKs? I can also try to recreate this on my end if you let me know what steps you've done.

Best regards,

Simon

[Calvin T]

CONFIG_LOG_BACKEND_RTT is set to Y. 

Yes, the same exact project and setup was used. We're using dev boards from the same rev. Further, I've tried with multiple different dev boards. We're using our own dev boards, but the boards aren't complicated and they work fine with my colleague's setup.

I can't swap boards with him easily, because he's in Italy at the moment. However, I'm having another engineer here in the office try. I'll update as soon as we have some results.

[Riley-Cameron]

Hello Simon,

I am one of Calvin's coworkers. We were able to get RTT working again after a normal flash, however when debugging (with & without reflashing) RTT does not work at all. 

Do you have any advice for getting RTT to come through during debugging?

Thanks!

Riley