Serial Wire debug Nucleo-WL55 JC1 SWO

[LEdou.1]

Hi,

I trying to debug on nucleo-WL55 with serial wire debug via SWO.

I have enable "Serial Wire Viewer (SWV)" in debug config, and add SWV ITM Data console (Config 0).

Even add this code :

int _write(int file, char *ptr, int len)
{
 /* Implement your write code here, this is used by puts and printf for example */
 int i=0;
 for(i=0 ; i<len ; i++)
 ITM_SendChar((*ptr++));
 return len;
}

With this line : printf("HelloWorld");

Did you know why it doesn't work? Is that possible to have serial wire on WL-55 ? I have all jumper on JP8 as we receive the nucleo-WL55.

My config :

 

 

Thanks

[LEdou.1]

Still nothing, Are we agree that we don't have to modify nucleo-WL to have serial wire ? And use it as we receive it ?

[Wijeden RHIMI]

Hello @LEdou.1 ,

Let's try to make those suggestions:

Could you please open SWV trace (there just enable pc sampling)

• If the data are shown in this view, then the issue is related to printf function: you make some errors in printf function.
• If you don't get the data, then the issue is related to another thing: you are using the pin of SWO to configure another alternate function in IOC.file, and maybe the board doesn't routing the pin to the link.

Wijeden,

[Wijeden RHIMI]

Hello,

It is stilling not worked? so let's try to make those suggestions:

Could you please open SWV trace (just enable sampling PC) and check:

• If the data are shown in this view >>>> the issue is related to the printf function (you make some errors in this function).
• If you don't get the date >>>the issue is related to the configuration in the ioc.file : maybe, you set up the pin of SWO to another alternate function, so the board doesn't routing the pin to the link.

Wijeden,

[LEdou.1]

Still not working...

Nothing on SWV Data Trace and nothing on SWV ITM Data Console.

Like you said, I have add "ITM_SendChar((*ptr++));" and "#include "stm32wlxx.h"" on syscalls.c

I don't understand why it dosen't work. Did you have a exemple project, which work ?

[Wijeden RHIMI]

Hi,

You could see this example in the screenshot bellow using CubeIDE 1.10.1 and NUCLEO-F429ZI.

 

Wijeden,

[LaurentL]

Hello,

I am pretty sure you have to look at the schematic of the nucleo, there is a solder bridge to set or to remove.

I don't have the board here to look but I am sure I did a hardware modification for the swo pin to be redirected to the STLink.

I just looked on the schematics, so it will depends on the hardware version you have, you can see the PB3/SWO pin has a DNF (Do Not Fit) solder bridge SB8 for SWO.

So, you must unsolder the SB31 that is set for ARD_PB3 and put it in place on SB8 for SWO.

Or, if not using the ARD_PB3 pin on Morpho connector, you can let the solder bridge SB31 and add one on the DNF (SB8) to have T_SWO connected.

SB numbers can vary on the hardware versions.

Rgds,

Laurent

[LEdou.1]

Thanks @LaurentL​  ans @Wijeden RHIMI​, my bad effectively, it was SB8 ! From de beginning I confused between SWDIO and SWO ... Sorry ! Tanks a lot again !