J link swd speed setting in nrf connect?

[Elppu]

How do I adjust the swd speed used by nrf connect RTT ? Currently it is 2000khz but more is needed. I need to transfer audio data to PC.

For some reason my current process require first opening RTT view in nrf connect and then run python script with pylink. I cannot get RTT started otherwise.

Also is it normal to get random garbage reads from the RTT ?

[Turbo J]

Buy a commercial J-Link, those can run dual digit MHz SWD connections.

Cheaper solution: Buy NRF5340 DK, use I²S between NRF41L15 and the NRF5340 DK MCU in audio-to-USB mode.

[Elppu]

Hi!

I have nrf54l15 dk with builtin probe. Is that probe slow? 

A bit noobish question but where is the speed defined in nrf connect project if i want to change it? For internal or external probe

[Vidar Berg]

Hi,

I'm not convinced that the SWD freq. is the problem here. I suggest increasing the RTT buffer size in your project configuration (CONFIG_SEGGER_RTT_BUFFER_SIZE_UP) to see if that helps. I'm not sure if it's possible to change the default SWD frequency for the RTT terminal in the VS Code extension. In any case, the SWD frequency is limited to 2 or 4 MHz when using the debugger on the DK. If you have an external J-Link probe, you could try testing with the J-Link RTT Viewer app, which allows you to specify the frequency. 

Also is it normal to get random garbage reads from the RTT ?

Generally no, but it can happen if the log buffers fill up.

[Elppu]

Hi!

I have already increased buffer size 

I have so far a bit naive printing as hex string, but the bandwidth is quite fast saturated already with one mic, and i need 2 - 4 mics. 4mhz might be enough if possible to set it.

[Vidar Berg]

Have you tried using the "immediate" logger mode as well?