STM32L082(CMWX1ZZABZ-078) not conneting to ST Link

[CChul.1934]

Hi, I have designed a custom board with some sensors and a CMWX1ZZABZ-078 chipset as MCU and Lora module. To design the board I have copied the schematic that Murata has in the datasheet of the module, I'm trying to connect the board to the computer to flash my code but ST link is always giving me the same error (Can't connect the target), I tried with a 10k pull up resistor connected to the MCU_RST pin but didn't work. I cant find the reason why this is not working, any ideas?

Thanks in advance for the help.

[Flavio Alves]

Thank you for your fast response.

I tested also on a stand alone ST-Link V2.

And the result is the same.

The set speed for 4 MHz in all cases.

I checked the power pins and they all all with 3.3V :|

What do you mean by system loader?

[Tesla DeLorean]

>>What do you mean by system loader?

The ROM base loader, via a USART, BOOT0 pulled HIGH

AN2606

https://www.st.com/content/ccc/resource/technical/document/application_note/b9/9b/16/3a/12/1e/40/0c/CD00167594.pdf/files/CD00167594.pdf/jcr:content/translations/en.CD00167594.pdf

Boards not running, so will need to check schematic and layout. Perhaps double check the netlist and pin list. Basically going to have to repeat all the due diligence work for the design.

Check module orientation and soldering.

[Flavio Alves]

Absolutely,

I'll do that. Thank you very much.

[Flavio Alves]

I got a solution to my problem:

1) There was a problem with the module assembly. After reworking, It was possible to finally run ST-Link Utility that recongnizes and connects to the board.

2) The connection was done just in "Hot plug" configuration, which was a little strange (on the discovery, I use "connect under reset" or "normal modes". Still, it was not possible to erase the memory and write new firmware on it.

-- The problem was similar to this one: https://community.st.com/s/question/0D50X00009XkZDo/how-disable-read-out-protection-?t=1584613723031

3) In my standard STM32 projects, I use to use NUCLEO SWD connector for development and firmware loading. I don't use the 3.3V, but I allways add it on the design if it is needed, which was the case:

-- Connecting the 3.3V from the board to the 3.3V to the ST-Link V2 (not the NUCLEO), it worked as expected.

Thank you for the fast response.

Best regards,