STM32L072CxY6 counterfeit?

[nagendranr22]

Hi,

I am using STM32L072CBY6/STM32L072CZY6 in one of the designs and due to non availability of stock with reputed dealers, we got couple of sample batches from lesser known distributors. Strangely all the boards that we assembled using these stock turned out to be unprogrammable! When I try to connect my board to STLink v2 programmer, I get an error as below:

Can not connect to target!

         Please select "Connect Under Reset" mode from Target->Settings menu and try again.

         If you're trying to connect to a low frequency application , please select a lower SWD Frequency mode from Target->Settings menu.

I looked at the date code marked on the IC and I am not able to make out if they are genuine or fake. Can someone identify if these are genuine ICs? Any help is appreciated, Thanks

[Tesla DeLorean]

I don't think ST offers real-time trace of product in the forum. You should perhaps work directly with sales and engineering you'd normally interact with. You could try the local sales offices, or as an Online Support Request (not the forum, via the support page)

Not clear if they want to insert themselves into third party transactions on the secondary markets.

Do you have secondary means to connect to the MCU in your design? ie via the System Loader (BOOT0=HIGH) and the UART for example? I'd check for signs-of-life via interaction there.

Using STM32 Cube Programmer or ST-LINK Utilities?

Is NRST connected to your debug header? You can't "connect under reset" without it.

Reduce speed of SWD connectcion for CM0(+) devices.

[nagendranr22]

Thanks @Community member​ for a quick response. I have contacted the sales team and they are working on connecting me with a technical expert.

Boot0 is currently pulled to ground and I do have means to make it high and access to MICON_TX and MICON_RX pins. I will pass on this info to our SW engineer and see if he can do something with it.

I am using ST-Link V2 and I do have NRST line connected to the programmer. Strangely I notice that the the NRST signal is always held low and I couldnt locate any short circuit on board! The NRST pin shows ~300k ohm impedance w.r.t ground goes low as soon as I power up the board. I see it happening in all 20 boards that we assembled!

[Tesla DeLorean]

NRST low, perhaps an orientation/pin-one type thing? Also the absence of VDDA/VSSA, which power the POR and PLL circuits

[nagendranr22]

I checked the orientation and seems ok. XRAY image of the IC after soldering looks okay (top view) but I am not able to reliably confirm if VDDA/VSSA are soldered properly.

Is there any tool (SW/HW) using which I can communicate with the device via UART by pulling BOOT0 high?

[nagendranr22]

I am attaching a portion of my circuit for reference. With this configuration I always see NRST is held low. I tuned the +1V8MCU power supply to 2.2V and still NRST was low. I connected +3V3MCU rail to VDD, VDDA and VREFP and surprisingly NRST got pulled high (3.3V). I got excited and tried programming the board but still the result was same. I put back the VDD, VDDA and VREFP to 1.8V and NRST was back to low state. I can see the controller is doing something internally but not able to figure out what!

 

I checked C46 and the value was 106nF, so I guess thats good. I tried removing C46 altogether and it didnt do anything.

Hi @Peter BENSCH​, please help if you can figure out whats going on. Thanks

[Tesla DeLorean]

>>Is there any tool (SW/HW) using which I can communicate with the device via UART by pulling BOOT0 high?

For quick testing I'd use RealTerm in hex mode.

The core would need to be running, which won't be occurring if NRST is clamped low.

The protocol is described in AN3155, as I recall. Want to connect at 9600 8E1 (Even Parity), sending an 0x7F pattern, looking for an 0x79 response.

[Jacob WOODRUFF]

Hi nagendranr22,

Your case has been flagged by one of our moderators for support from the ST team and a case has been created in order to help with that.

Anyone who is looking to identify if an ST part is genuine or not can just submit pictures or the marking data to ST through the Support and Community tab of the ST.com website when you submit a case.

Regards,

Jake

ST Support

[Tesla DeLorean]

Thanks Jacob.

Might I suggest a "Authentic Parts / Supply Chain Integrity" sub-forum ?

[Nikita91]

Yes to find this important information in one place. If there is a lot of counterfeits, there are probably several victims.