STM32CudeProgrammer tries to start connection and MCU responds, but too late?

[jlthompson]

I'm trying the program an STM32G0B1RET with the STM32CubeProgrammer. It seems the programmer sends a 0x7f and the MCU responds, but maybe too late to connect?

[jlthompson]

And BOOt0 is being held high:

[TDK]

Does your program use that COM port? Doesn't look like the bootloader is responding, but something else.

BOOT0 is ignored on default option byte settings. See AN2606 for how to start system bootloader.

[Tesla DeLorean]

It's the wrong response.

What has been programmed into this part?

Can you program your own app via SWD, ie SWDIO/SWCLK ?

Using PA2/PA3 ? anything else wired to the MCU?

https://community.st.com/t5/stm32-mcus-products/programming-a-virgin-stm32g0b1/td-p/829926

[jlthompson]

As you can see from the images, the programmer is set for 115200 baud, even parity, and the BOOT0 line is held high. I have done a Full Chip Erase, so the MCU should be just as it comes from the factory, right?

The MCU is on a NUG0B1RE$AU2/NUCLEO-G0B1RE development board. I've broken off the J-LINK part of the board and have its TX and RX lines connected to J2 and J2 of the MCU's board, so I'm using the ST-LINK board as a virtual COM port. It behaves the same way if I use an FTDI cable instead. At this point, I have to give up and say that, contrary to claims, you cannot use STMCubeProgrammer to program a factory-fresh MCU using the serial ports according to the AN 2606 and reference manual directions. That's a bug, in my opinion.