I have a question regarding the STM32L083CZT6 microcontroller. I have designed a custom board using this microcontroller, but it's not working!! Do you have any tips?

[AHamz.2]

I have tested the microcontroller with different boards and all have the same problem.

I have noticed that the voltage across the NRST is 0V, which I think means that the microcontroller is damaged (There is no short circuit in the system).

I have connected the microcontroller to the PC through a serial wire debugger (using STLINK-V3MINI) and it says MC not found.

I have designed a custom board using STM32F4 before and I didn't have a problem before.

Do you have any tips to find the problem?

Thanks

Here is the Circuit design

[Andrew Neil]

also VDD_USB ?

EDIT

Oh - @Community member​ already said that

[Tesla DeLorean]

Walking the Net List is pretty high up on our checklist here, definitely looking for orphans or little disconnected islands.

Power nets particularly, as symbols and naming is frequently not consistent and the tools may be sensitive to case, spaces, underlines.

[waclawek.jan]

> Walking the Net List 

I prefer beeping through the real circuit. Or both.

JW​

[Tesla DeLorean]

Well I'd rather do it before I get a box of PCB..​

[Andrew Neil]

"I prefer beeping through the real circuit"

but, if the schematic doesn't show a connection to bleep, you're not going to know to bleep it ... ?

I think that's the trouble with these so-called "schematics" which are just a load of isolated blocks and show no connections.

:pouting_face:

https://twitter.com/matseng/status/1539519060106432513

[AHamz.2]

Yes, all grounds are properly connected

The target voltage is 0.00 V and sometimes it is 0.03 V

The error message is Error: ST-LINK error (DEV_TARGET_HELD_UNDER_RESET)

[AHamz.2]

I have just connected the VDDA/VSSA as well as the VDD_USB

The error message now is Error: ST-LINK error (DEV_TARGET_HELD_UNDER_RESET)

[Andrew Neil]

@AHamz.2​ "The target voltage is 0.00 V and sometimes it is 0.03 V"

Well that's clearly wrong, then - isn't it?

The ST-Link should be seeing the supply voltage of the Target; if it's seeing 0V, then you clearly have either a wrong or faulty connection to the board, or a wrong or faulty connection to the VDD pin in the debug header. Or both.

 EDIT

Oh, you don't have a Target voltage connection in your debug header.

That's wrong!

[Andrew Neil]

and is the ST-Link still reading the Target Voltage as zero?

See above:

[Andrew Neil]

you need the Target Voltage connection to the ST-Link

 

As for any other debug probe; eg,

 

see also: https://documentation-service.arm.com/static/5fce6c49e167456a35b36af1