Is there a list of SBs on STM32F723E-DISCO?

GlitchyCat · ‎2026-05-22

Is there a standard list of SB's? I cannot for the life of me figure out the SB's on the STM32F723E-DISCO, and none of the manuals mention anything about them other than if open is on or off. I am specifically trying to use the debugger for my custom PCB based off the same MCU.

Any help would be greatly appreciated!

Andrew Neil · ‎2026-05-23

Usually, you would expect to find this in the User Manual - but it doesn't seem to be there at all.

So you'll just have to look through the schematics...

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

waclawek.jan · ‎2026-05-23

[I've separated this post from this thread, as it has a different scope. Next time, please start your own thread, with perhaps giving link to other possibly related threads.]

I've had a look at UM2140 and indeed, contrary to older DISCO boards, no SB list there. ST appears to have gradually lost interest in making the DISCO boards an attractive way to introduce potential users to the individual STM32 families; these days they barely make new DISCO boards at all (and they even frown upon the DISCO/DISCOVERY name these days). Instead, they focus on (read: throw the money onto) various Cubes. Well, that's their decision, with which I cannot agree less, but can do nothing but accept it and perhaps rant here a bit... :)

A better source for SB's positioning (and from that, judging on their functionality) may be the DISCO board's schematics, a pdf under "CAD RESOURCES" tab on the DISCO board's web folder.

> I am specifically trying to use the debugger for my custom PCB based off the same MCU.

I'm not sure why would you need to know about the SBs at the DISCO board to achieve this. Do you want to use the DISCO board's STLink to do that? Isn't buying a standalone STLink an option for you?

JW

Andrew Neil · ‎2026-05-23

@GlitchyCat wrote:
I am specifically trying to use the debugger for my custom PCB based off the same MCU.

I think that's a separate question, which deserves a separate thread.

As @waclawek.jan said, you can always link back to this (and other) threads for reference - if you feel it helps.

I think the question here - about the list of SBs - has been answered, so please mark the solution on whichever post you think provided the best answer (not this one!)

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

waclawek.jan · ‎2026-05-23

Hi@Andrew Neil ,

isn't UM2140 the proper user manual for this board? Am I overlooking something?

Btw. there are relatively few solder bridges on this board. It's quite crammed and it is not really intended to provide flexibility in its usage beyond handling the onboard circuitry. This was that era of the DISCO boards where the Nucleos were already available so those were intended to serve for more flexible purpose.

IMO the onboard STLink is unusable for programming other boards. While there are SB10..SB13 to disconnect STLink from the onboard target, there is no connector at the STLink side to bring its signals out of the board, only a "TAG" footprint, which is intended for the opposite purpose, to program the on-board STM32 using an external STLink (or other debugger).

JW

Andrew Neil · ‎2026-05-26

@waclawek.jan wrote:
isn't UM2140 the proper user manual for this board?

Yes, it is.

In that manual, the only occurrences of "SB" (other than in "USB") are here:

If this were source code, the compiler would issue a warning: "'SB' is defined but never used" !

@waclawek.jan wrote:
It's quite crammed and it is not really intended to provide flexibility in its usage beyond handling the onboard circuitry.

I agree totally.

@waclawek.jan wrote:
IMO the onboard STLink is unusable for programming other boards.

Agreed.

@GlitchyCat if it was intended to use the ST-Link to program/debug external targets, there would be a section in the User Manual detailing how to do it. But there isn't.

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

Mike_ST · ‎2026-05-26

Hello,

>> I am specifically trying to use the debugger for my custom PCB based off the same MCU.

For MB1260 rev D, you can try to remove SB10 to SB13 and take the debug signals from there.

Or make, before hand, a firmware for the Disco that keeps PA13-PA14-PB3 silent (analog in mode, or digital input with no pul), so maybe you wont have to remove the solder bridges.

It is possible you'll have to remove SB13 anyways.

Never tried myself, you have to experiment, maybe there are other constraints I don't see.

Andrew Neil · ‎2026-05-26

@Mike_ST but why is there no documentation of the SBs in the User Manual ?

Also can you confirm, as @waclawek.jan suggested, that the ST-Link on this board is not intended to be used with external targets?

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

Mike_ST · ‎2026-05-26

Hello Andrew,

>> but why is there no documentation of the SBs in the User Manual ?

This board design is from 2016, there was a time where it wasn't requested to the tech writer,

as the schematic was considered as the reference.

It had the advantage to avoid misalignment between schematic/PCB and the documentation when issuing another revision of the PCB.

>> Also can you confirm, as @waclawek.jan suggested, that the ST-Link on this board is not intended to be used with external targets?

Absolutely, by design, it is not intended to be used with external targets.