Why is the SB9 Bridge on STM32F429I-DISC1 Not Soldered?

[Shreayas_Acharaya]

Hi St community,
I noticed that the SB9 bridge on the STM32F429I-DISC1, which connects the SWO pin of the ST-Link to PB3 on the STM32, is ideally not soldered by default.
Is there any specific reason for this? Does it affect the SWO functionality or debugging in any way? Should it remain unsoldered unless needed for certain configurations?
Looking forward to your insights!

Thanks!

[Andrew Neil]

Presumably, because they thought that fewer people would want to use SWO than would want to use PB3 as a normal GPIO?

 

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@Shreayas_Acharaya wrote:

Does it affect the SWO functionality or debugging in any way?

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With the Target's SWO output disconnected from the ST-Link, you obviously can't use the SWO feature

 

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@Shreayas_Acharaya wrote:

Should it remain unsoldered unless needed for certain configurations?

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If you're not going to use SWO, then there's no need to do anything - leave it unsoldered.

 

[Karl Yamashita]

SWD debugging/programming only needs SWCLK and SWDIO, so T_SWO is not needed.