STM32H755XI gets so hot

[TDP_0000]

I checked with the Uploaded File schematic board.

I'm using STM32CubeProgrammer.

Connect from PC via UART.

I confirmed that the UART is connected with STM32CubeProgrammer.

​Software has not been written yet.

In that state, the MCU became so hot that I couldn't touch it.

Could you please tell me the possible reasons?

[PGump.1]

Hi,

• Your MCU is broken. Possibly a Latch-up condition.
• GPIO(s) that are tied to GND are configured as High Outputs.

I hope that helps

Kind regards
Pedro

[TDP_0000]

Hello,Pedro

When I set Boot 0(E8) to Lo, it no longer heats up.

If I turn on the power before writing software, are there any GPIOs that are output?

[TDP_0000]

Are there any signals such as GPIO that are turned on when Boot 0 is Hi?

[PGump.1]

Hi,

Possibly. You need to read "AN2606 STM32 microcontroller system memory boot mode"...

KInd regards
Pedro

[TDP_0000]

Sorry, I didn't understand clearly even after reading it.

Since I2C is an open drain, I don't think there is any current consumption even if the load is GND.

Could the current consumption be caused by another signal USART, SPI, DFU, FDCAN?

[PGump.1]

Yes.

Kind regards
Pedro

[LCE]

Oh my, you connected ALL unused GPIOS to GND?

Bad idea when not knowing there default state after power up.

Check / do the following:

- check your MCU power settings: LDO is on ?
   if you are using HAL, look for something like: HAL_PWREx_ConfigSupply(PWR_LDO_SUPPLY);

- first thing in your code after clock configuration: set all unused GPIOs to input without pull-up and without alternate function

[TDP_0000]

Connecting all unused GPIO pins to GND is based on "AN4899 6.1 Avoid floating unused pins".

If an external PU/PD is required when the power is turned on(Boot0=0), I think you should write that.

When Boot0=1, there is no heat generation, so I think this is correct.

Therefore, I wanted to know which GPIO is changing when Boot0=0.

[TDP_0000]

Sorry, Boot0 was written backwards.

Connecting all unused GPIO pins to GND is based on "AN4899 6.1 Avoid floating unused pins".

If an external PU/PD is required when the power is turned on(Boot0=1), I think you should write that.

When Boot0=0, there is no heat generation, so I think this is correct.

Therefore, I wanted to know which GPIO is changing when Boot0=1.