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

[Peter BENSCH]

Welcome, @AHamz.2​, to the community!

The information is not really sufficient to help you. The STM32L0 differs from the STM32F4 family in many ways. Also, this ultra low power family is typically used when you want to save a lot of energy. For example, one uses one of the powersave modes in which the debugger can only access with Connect under Reset.

You have also not uploaded the schematics from which one could possibly recognise what leads to the problem.

Regards

/Peter

[AHamz.2]

I have just uploaded the schematic. Thanks.

What would be the difference between the two families in the case of the Circuit Design?

Best

Ahmed

[Tesla DeLorean]

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[Andrew Neil]

"I have designed a custom board"

Was the design carefully reviewed?

Were the bare boards inspected & tested for continuity, shorts, etc?

After assembly, were the boards inspected & tested for continuity, shorts, etc?

Have you tested for correct voltages at all supply pins?

etc, etc, ...

[AHamz.2]

Yes, the board was carefully reviewed, please refer to the Circuit design.

There are no short circuits. From the manufacturing part, the PCB is all good (I have tested different microcontrollers on different signed boards and still the same problem) Also after assembly all good

The voltage is stable at all the VDD pins as well

Best,

Ahmed

[Andrew Neil]

"The voltage is stable at all the VDD pins"

And are all the VSS pins actually connected to 0V ?

"STLINK-V3MINI ... says MC not found"

Does it see the correct Target voltage?

[Tesla DeLorean]

Does the design have a schematic?

Obvious things to check would be part orientation, as placed,

pin designations, AVDD / AVSS connections.

[waclawek.jan]

> AVDD / AVSS connections.

= VDDA/VSSA, are they properly connected?

(Also the VDD_USB, but that probably does not influence running as such)

[Tesla DeLorean]

If I'm not mistaken the VDDA net isn't connected to anything.

Lack of VDDA which powers the PLL and POR circuits, will clamp NRST to ground.

[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..​