STM32G0 that just won't connect

[satyamfifa]

Hey All,

I made my first STM32 board using STM32G0B1RE, it arrived today, since it's blank I expected the MCU to jump into bootloader and start the DFU, however this did not happen, MCU was not detected at all by the USB, I checked further and USB DP was not pulled high which was unexpected.

To check if the MCU has been entered the bootloader I check the UART TX and I2C SCK pins, and they are indeed high, indicating that MCU was indeed entered the bootloader. However, MCU is again not detected by UART.

Finally, I decided use another NUCLEO board as a programmer with the SWD interface, again, the MCU is not detected. I expect the SWD interface to work irrespective of bootloader.

Pulling up or down the BOOT0 makes no difference. I probed the board, and everything seems normal, voltages connections etc. I have 220 ohms series resistor on the SWD interface, which is little on the high side, but I don't think that should make a difference.

It just seems like MCU enters into bootloader, tries to initialize the peripherals, and just freezes. Only thing that seems to be working it the RESET pin, when it's pulled low all GPIOs go low.

Kind Regards,

Sparsh

[DavidAlfa]

Schematics?

[satyamfifa]

Well, I made a blunder, as it turns out STM32G0R1BETx doesn't have the same pinnout as STM32G0B1RETxN even though both are LQFP64 package. Also I learnt that x at the end of part number can sometimes be a little misleading as I learnt the hard way.

But fortunately for me, I was able to make my board work by patching just one wire.

[ Specified attachment is not available ]

[Berni]

Yep been bitten by that one too before.

Seams like ST really loves to make alternative pin outs for a chip designated by a letter way at the end of the partnumber where you might assume it just means a temperature range or reel package type or something irrelevant like that, but nope.

At least this one is reasonably consistent, i had a while section of IO pins shifted over due to an extra letter on the end of the partnumber.