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Associate II
April 12, 2026
Solved

V3 MINIE not working with U575 custom board

  • April 12, 2026
  • 6 replies
  • 368 views

I have a 14-pin connector and a 6-pin fall back connector. I can connect the 6-pin SWD via st-link V2 on a nucleo board but I cannot connect with a V3 MINIE on the 14-pin. Any ideas? I followed the schematic for a 14-pin connector I found on a NUCLEO board, which had a 100 ohm resistor on GND detect. I have bypassed it but the result is still the same. Apart from that and the TX/RX, the wires are the same for the 6-pin connector that works?

Here's my output:

CDLiveWatchSetup
Info : auto-selecting first available session transport "hla_swd". To override use 'transport select <transport>'.
Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD
Warn : The selected adapter does not support debugging this device in secure mode
adapter speed: 24 kHz

none separate

Info : Listening on port 50004 for tcl connections
Info : Listening on port 50005 for telnet connections
Info : clock speed 24 kHz
Info : STLINK V3J14M5 (API v3) VID:PID 0483:3754
Info : Target voltage: 3.272000
Error: init mode failed (unable to connect to the target)
Best answer by WellLeithed

I've just noticed that the footprint of the connector has pins 5 and 6 mixed up. Anyone have any ideas for removing the trace connecting pins 6 and 7 under the 14-pin connector (hahaha!)? Thank God for the 6-pin fallback the board has. And thank you for your willingness to help.

6 replies

TDK
Super User
April 12, 2026

Can STM32CubeProgrammer connect?

If not, probably a wiring mismatch or bad connection somewhere.

It detects voltage, so that part is good.

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Associate II
April 13, 2026

It can't, although I connected my MINIE V3 to a nucleo board so that's not the problem.

 

I followed this schematic (https://www.st.com/resource/en/schematic_pack/mb1549-u575ziq-c03_schematic.pdf) but the 100 nF capacitor on NRST doesn't seem to go to zero when I connect the debugger. It gets to about 1.8V. One thing I didn't do is add the ESD protection.

TDK
Super User
April 13, 2026

When the board is connected to the MINIE V3, how is it powered? The programmer does not provide power.

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Andrew Neil
Super User
April 13, 2026

@WellLeithed wrote:

I have a 14-pin connector and a 6-pin fall back connector.

Please show the schematics.

How to write your question to maximize your chances to find a solution

 


@WellLeithed wrote:

I can connect the 6-pin SWD via st-link V2 on a nucleo board but I cannot connect with a V3 MINIE on the 14-pin.

What about the other combinations ?

 14-pin6-pin
st-link V2?OK
V3 MINIEfail?

 

PS:

Can the V3 MINNIE connect to anything else?

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.
Associate II
April 13, 2026

Captura de Tela 2026-04-13 às 11.05.11.png

Captura de Tela 2026-04-13 às 11.05.37.png

I copied the nucleo schematic I linked earlier.
As I mentioned the MINIE is fine as I connected to nucleo board and visualised it on CubeProgrammer. 
I cannot complete the table as I'm unable to connect the parts in the manners suggested.

Associate II
April 13, 2026

Captura de Tela 2026-04-13 às 11.12.32.png

And here's the 6-pin connector.

TDK
Super User
April 13, 2026

Schematic is okay. Maybe the footprint on the connector is wrong, or it's installed in reverse.

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Andrew Neil
Super User
April 13, 2026

Or an error in the wiring between the ST-Link and the connector ...

 

Can the V3 MINNIE connect to anything else?

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.
WellLeithedAuthorBest answer
Associate II
April 13, 2026

I've just noticed that the footprint of the connector has pins 5 and 6 mixed up. Anyone have any ideas for removing the trace connecting pins 6 and 7 under the 14-pin connector (hahaha!)? Thank God for the 6-pin fallback the board has. And thank you for your willingness to help.

Associate II
April 13, 2026

I've just noticed that the footprint of the connector has pins 5 and 6 mixed up. Anyone have any ideas for removing the trace connecting pins 6 and 7 under the 14-pin connector (hahaha!)? Thank God for the 6-pin fallback the board has. And thank you for your willingness to help.

Andrew Neil
Super User
April 14, 2026

@WellLeithed wrote:

 Anyone have any ideas for removing the trace connecting pins 6 and 7 under the 14-pin connector 


Use an adaptor cable / interposer to correct it.

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.