STM32H533 debug interface failure under environment test

[ztliu722]

Hi, we have perform a series of environment test for STM32H533, including thermal cycle and vibration test.

Durting vibration test, DUTs are powered off, while under thermal cycle test, DUT is powered on.

After the test, all application part still function as expected, including UART, ADC, basic IO...etc. However, we've found that three, out of six, DUTs can NOT be accessed through debug interface SWD. 

Moreover, there are few things abnormal,

1. nRst pin is about 3V, even through VDD is 3.3V
2. ST-Link can NOT drive nRST pin to 0V, only 1.5V to 2V.
3. same as SWCLK, cannot be driven low to 0V, as nRST pin.

Is there anything we can do to further identify the root cause of the failure?

Can anyone shed some light on this?

Zt.

[Andrew Neil]

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@ztliu722 wrote:

DUTs can NOT be accessed through debug interface SWD. 

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How do you try to "access" them?

What, exactly, happens - show logs, etc

Show the schematic - at least the debug connection part

How to write your question to maximize your chances to find a solution

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@ztliu722 wrote:

Is there anything we can do to further identify the root cause of the failure?

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How to solve connection errors when connecting and programming the STM32 target board.

How to solve debugger connection issues

maybe also:

How to recognize a genuine ST-LINK/V2 versus a cloned one