"No device found on target" trying to flash XM125 radar board with ST-Link V2.

[blank_supportgis]

I'm currently experimenting with an XM125 radar board . As seen on page 15 of the module's datasheet, this board essentially contains an STM32L4 MCU with the necessary external components and the radar sensor. All pins of the MCU are exposed through the board. So, essentially, I'm connecting directly to the STM32L4.

My Problem

I'm struggling with flashing something to the controller. I know this has been asked (and solved) a thousand times, but I simply cannot find the problem here.

When attempting to flash a default project by the manufacturer using an ST-Link V2 (genuine, not clone), I get the following output in STM32CubeIDE 1.17.0:

STMicroelectronics ST-LINK GDB server. Version 7.9.0
Copyright (c) 2024, STMicroelectronics. All rights reserved.

Starting server with the following options:
 Persistent Mode : Disabled
 Logging Level : 1
 Listen Port Number : 61234
 Status Refresh Delay : 15s
 Verbose Mode : Disabled
 SWD Debug : Enabled
 InitWhile : Enabled

Target no device found

Error in initializing ST-LINK device.
Reason: No device found on target.

STM32CubeProgrammer (2.19.0) gives a very similar output:

12:52:16:265 : UR connection mode is defined with the HWrst reset mode
12:52:16:390 : ST-LINK SN : 37FF6F063143433923131843
12:52:16:391 : ST-LINK FW : V2J45S7
12:52:16:391 : Board : --
12:52:16:391 : Voltage : 3,23V
12:52:16:392 : Error: Unable to get core ID
12:52:16:392 : Error: No STM32 target found! If your product embeds Debug Authentication, please perform a discovery using Debug Authentication
12:52:16:404 : Disconnected

I've also tried pulling BOOT high during startup and changing the reset modes between Software, Hardware and Core, but the result was the same.

My Setup

I'm using a serial-to-usb interface stick to generate the source voltage of 3.3V. I'm additionally using a voltage divider to get the 3.3V down to 1.8V, since this voltage is required by the radar sensor. The following schematic outlines my setup:

In the attachments, you find an image of my setup, and my test project.

[TDK]

How much power is drawn on 1.8V? Might be being pulled too low.

Why are most of the grounds not connected?

[Andrew Neil]

Have you tried https://developer.acconeer.com/ ?

[blank_supportgis]

The radar sensor isn't activated and therefore draws almost nothing, my multimeter isn't even sensitive enough. The overall current draw is around 13mA.

As for the unconnected grounds, I have no excuse but laziness. I figured, one ground connection should be good enough for testing. Am I wrong here?

[TDK]

For STM32 ground pins, they all need connected. I don't have information on how the module grounds connect to STM32 grounds. Probably that's worth checking out. A connectivity check between them might yield an answer.

[blank_supportgis]

Yes, I tried acconeer's developer section But I didn't find any help there for my particular problem.

I think, this is a standard STM32 related question that isn't made special by the radar module. The XM125 is essentially a bare minimum STM32 MCU with one additional sensor. 

[blank_supportgis]

The XM125's datasheet at https://developer.acconeer.com/download/xm125-datasheet/?tmstv=1741766474 shows that all VSS pins and VSSA are connected to ground and all ground pads on the module are connected together.

Sorry for the inconvenience, but I don't feel well posting schematics from acconeer's datasheets without consent.

[Andrew Neil]

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@blank_supportgis wrote:

I think, this is a standard STM32 related question that isn't made special by the radar module. 

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But there could be something in their design that needs to be taken into account.

eg, have the locked-out the SWD access?

They have their own forum: https://support.acconeer.com/support/home

[Andrew Neil]

Have you tried connecting under hardware reset ?

Does  this ST-Link work with other targets?

PS:

Are you sure you have the ST-Link connections correct?

There was a case recently where the problem was misinterpreting the ST-Link pinout...

[blank_supportgis]

I tried connecting under hardware reset with the same result.

I currently don't have access to other targets, but I can check this tomorrow and let you know. I do have access to another ST-Link however. Same result.

I've checked the connections again using the XM125's datasheet and the ST-Link's datasheet and also verified proper connectivity with a multimeter. The wiring is as shown in my schematic.