Issue with VCAP Voltage

[Amruth]

HI,

 

I am using STM32H745BIT6 ST controller in my custom board.

Configured in Direct SMPS mode. 

When the board is powered on the VCAP voltage is 1.2V and settling at 1V as expected when we try to flash the program to controller the voltage is same, but when we are trying to enter into debug mode the voltage is dipping from 1V to 0.6V and after 5uS its coming back to 1.2V.( Image is attached for reference)

Due to this issue, I am not able to enter to debug mode controller is getting disconnected and showing the pop-up as TARGET IS LOST.

 

I have taken all the precautions mentioned in datasheet and reference manual.

1) Shorting all three VCAP pins.

2) Connected two 2.2uF capacitor near to the pins.

3) Even tried with higher capacitor value.

4) Checked the shorts in the pins and board with the help of multimeter.

5) The PWR_CR3 register is also set to Direct SMPS mode and verified the last 4 bits as 0100.

6) Verified in the IOC that it is configured to Direct SMPS mode.

7) Reset pin is also verified it is staying high during the VCAP voltage dip.

It's not helping and I am stuck.

 

Is there anything that I need to check or try to get the controller into debug mode.

 

[mƎALLEm]

Hello @Amruth and welcome to the ST community,

I have the impression that's the same issue described in this post. and I suspect you are colleagues. If yes we prefer to keep the discussion in the other thread.

Thank you for your understanding.