NUCLEO-L433RC-P SWV Not Working

[jdawkins]

Hi,

I have an external PCB using STM32L432KCU6 to program and debug.  I can program this using the NUCLEO-L433RC-P (MB1319C) and NUCLEO-L476RG development boards in STLink configuration.

Using the L476, I can see the output of the SWV from printf (MCU freq is 4 MHz, matched in STM32CubeIDE software or ST-Link Utility).

If I replace the programming board for the NUCLEO-L433RC-P, I can still interact with and debug the external MCU, but the SWV output no longer works.

If I remove the Idd pin from the NUCLEO side of the board (i.e. with the inbuilt L433 chip) then the STM32CubeIDE or ST-Link utility no longer recognise any target device on the SWD bus.

In both cases, the CN2 connectors are configured as ST-Link (i.e. jumpers disconnected).

Any advice on why the SWV would not work in this second case is appreciated.

Regards,

Jonathan

[Tesla DeLorean]

With the NUCLEO you need to disconnect SWDIO, SWCLK and SWO from the on-board target, the first two via the jumpers that you've removed, the latter via a Solder Bridge (SB)

[jdawkins]

Hi - can you confirm which of the SWO solder bridges you are referring to? SB11 (through), SB10 (level shifter) or one of the reserved SBs?

[Tesla DeLorean]

Should be SB11, but looking at the schematic this is in the wrong location, and you might have to removed the level shifter or cut the trace out of it so it's not driving into T_SWO

@STTwo-32 please have someone review, SB11 disconnects input to level shifter, not the output

https://www.st.com/resource/en/schematic_pack/mb1319-l433rc_p-c02_schematic.pdf