STM32G0 don't start and connect after update

[YDann.7]

Dear,

I have a big problem on a STM32G070 and I don't know what I can do to solve it.

The system is composed of 2 boards with a STM32G0B1 for the first (master board) and a STM32G070 for the second (slave board).

The 2 MCUs are connected by UART and this link is used to update the slave MCU by the first using the STM32 bootloader.

The setup was the first MCU (master) programmed with the firmware and the MCU (slave) full erase with the default option byte value.

In a first time, I programmed the slave MCU with the STM32 UART bootloader from the master mcu and it was OK. The slave MCU worked well. I rewrite the option byte of the slave MCU by the firmware to be able to used the GPIO BOOT 0 pin as legacy mode.

In a second time, I tried to upgrade again the slave MCU using the master and it doesn't worked. I don't removed the power of the boards between this 2 tries.

And now, I'm not able to connect to the slave MCU using STM32CubeProgrammer.

I have "Error: No STM32 target found!" and "Voltage: 0.01V" even if I have 3.3V on the pin 1 of the SWD connector and a high level on the NRST pin. I also tried some differents "Mode" and "Reset mode" configuration without success.

And now I don't know what can I try to do come back to life this MCU.

[Sco]

Hello YDann

If you mean, the CN11's pin 1 is always a low level, even you give it a 3.3V?

[YDann.7]

Hi Sco,

Thank to try to help me.

On the pin 1 of CN11 connector of the ST link I have 3.3V. On the pin 5 of the connector (NRST pin), I also have 3.3V.

So the MCU is correctly powered and no in reset. Even with this configuration, I can't connect with the STM32CubeProgrammer

[Sco]

Hello YDann

In this situation, it is better to confirm that if this power "3V3_STLK" is alive? "3V3_STLK" is the power input for ST-LINK MCU. You may measure this power through "C6" or "C7" at the top side.

[Sco]

In case I misunderstanding, would you please share me the status of the "ST-LINK"?

[Sco]

[YDann.7]

On C6 and C7 of the ST link, I have 3.3V.

And the ST work well because I'm able to program another board.

[YDann.7]

I updated the STM32CubeProgrammer to the latest version and I tried with a lot configuration (Mode and Reset mode).

But I always have the same error.

[Sco]

For the target voltage = 0.01V, you can have a confirm that, if "AIN_1" is "0V" or"1.6V". You may measure this power in R22.

[TDK]

Target voltage: 0.01V suggests the chip doesn't have power, despite whatever you're measuring.

How are you powering the board? Note that the debug connector does not provide power.

[YDann.7]

@Sco​ On the R22 resistor, I have 0V. But I use an old ST-Link cutted from an STM32F030R8 nucleo board. And this resistor is connected to the pin 6 (SWO - Reserved)

So, the component denomination could be different.

If I compare a nucleo schematic and mine, the "AIN_1" signal seems to be connected to the debug connector (pin 1) through a resistor not fitted. On my ST-Link, it seems to be the resistor R9 (not fitted) and I have 3.3V on it.

@TDK​ My slave board is powered by the master through a FPC cable. And the slave board (MCU) is correctly powered. I didn't change something between the 2 try.