Connecting STM32 NUCLEO board to an external debugger (ARM Keil ULinkPlus)?

[Spectramax]

Hello,

I'm following this guide (https://mcuoneclipse.com/2015/08/22/debugging-stm32f103rb-nucleo-board-with-with-segger-j-link/)

The board I am using is NUCLEO-L4R5ZI. I've connected the following pins to the 10-pin ARM connector:

 

I've also tied the VDD_Target/VTref pin to 3.3V.

When I launch Keil uVision5, I go to Project options and select the debugger. I am getting a "RDDI-DAP Error".

Please do not suggest I use the built in ST-LinkV2 debugger as a solution.

Thank you for your help!

[AvaTar]

> Please do not suggest I use the built in ST-LinkV2 debugger as a solution.

Why not ...?

Have you verified that all SWD connections from the target to the ST-Link are really separated ?

How long are the cables ?

And using the internal ST-Link, have you verified the target works fine ?

[Tesla DeLorean]

Don't use that connection for SWDIO and SWCLK, go in via the target side of the jumper pins.​

[Spectramax]

Thanks. I have already checked that the Target is working well with the built in ST Link.

@Clive Two.Zero : I will try this out and report back!

[Tesla DeLorean]

Specifically CN4, the lower pin on each pair connects to Target SWCLK (NORTH), SWDIO (SOUTH)

[Spectramax]

I just connected the SWDIO and SWCLK to the target side through CN4 with the rest of the stuff still in the CN5 connector.

I also have another board NUCLEO-F030R8 with the Stlink portion of the board snapped off. Perhaps I should try connecting directly without the STlink MCU messing up the signals?

Still no luck :( here is the pic:

[Tesla DeLorean]

You seem to have 2 and 4 switched in your picture vs your chart 2=SWCLK, 4=SWDIO, would me easier if you'd draw them in numeric/pin order

[Spectramax · Accepted solution]

@Community member​ No, I think it is correct. Anyhow, I also swapped them and no luck. Here is a cleaner pinout and connections.

Is there a problem with CMSIS-DAP compatibility? I am curious why this won't work :(

[Spectramax]

Looks like I might have found the problem. The 10-pin fanout cable's pin 1 (Red wire) is not on the same side as the 10-pin socket on the ARM UlinkPlus debugger.

Here is a picture of how the cable connects to the socket.

[Spectramax]

Yep, that was indeed the problem. I am now able to connect.

Anyone who is reading this thread in the future, please use the diagram above to connect to your STM32 Nucleo board and Ulink/Ulink2 or UlinkPlus debuggers from ARM Keil.

Everything is working great. Thanks for the help from @Community member​ and @Community member​ .

FYI - The reason why I'd like to use the ARM UlinkPlus debugger is first of all, I paid $700 for this so I might as well use it for faster flashing and debugging. It had trace functionality as well as power metrics, discrete IO for production testing. It is a great little ******!

Closing this thread, thanks.