2022-06-22 07:44 AM
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
2022-06-22 08:02 AM
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
2022-06-22 08:28 AM
"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, ...
2022-06-22 08:57 AM
Does the design have a schematic?
Obvious things to check would be part orientation, as placed,
pin designations, AVDD / AVSS connections.
2022-06-22 08:58 AM
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
2022-06-22 09:00 AM
That did not succeed, showing "image is not available" here
2022-06-22 09:04 AM
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
2022-06-22 09:20 AM
"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?
2022-06-22 09:45 AM
> AVDD / AVSS connections.
= VDDA/VSSA, are they properly connected?
(Also the VDD_USB, but that probably does not influence running as such)
2022-06-22 10:10 AM
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.