Could ESD kill my STM32 board? OLED screen stopped working

[durna]

I’m using an STM32 board to drive an SSD1322 128×64 OLED display with my own driver library. It used to work fine without issues. Without changing the code, the display suddenly became completely unresponsive.

- Power supply shows 0A current draw (normally it used to pull around ~0.3A).

- During debug, I noticed something strange: inside MX_GPIO_Init() the code enters, but it hangs at

GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;

and never progresses beyond that line.

I double-checked all hardware connections multiple times, nothing seems wrong.

When I swapped to another STM32 board of the same model, everything worked again without any changes.

This makes me suspect a hardware fault on the original board (possibly ESD damage).

My questions:

- What should I pay special attention to when debugging this kind of issue?

- How can I pinpoint the exact root cause (e.g., RAM/stack corruption, HardFault analysis, hardware measurements)?

- What’s the recommended way to solve this and prevent it in the future (ESD protection, design practices, etc.)?

[AScha.3]

> What should I pay special attention to when debugging this kind of issue?

You cannot "debug" a "dead" or "sick" cpu , to find out, why its "sick".

You only can prevent it, never let an ESD on a pin...

see, what our new friend telling:

ESD prevention methods include grounding personnel with wrist straps, using ESD-safe workstations with dissipative mats and chairs, controlling humidity (40-60% RH), implementing anti-static packaging, wearing ESD-safe clothing and footwear, and using ionizers in areas where grounding is impractical. Proper education and training for personnel on ESD control are also crucial. 

Grounding & Workstations

• Wrist Straps:

  Wear anti-static wrist straps connected to a ground point to safely discharge static electricity from your body to the ground. 
• ESD Mats & Flooring:

  Use anti-static or conductive floor mats on work surfaces and install conductive flooring to prevent static build-up. 
• Grounded Chairs & Workstations:

  Ensure chairs and workstations are grounded to dissipate any static charges. 

Environmental Controls

• Humidity Control:

  Maintain a relative humidity of 40-60% to reduce the buildup of static electricity. 
• Remove Insulators:

  Eliminate static-generating items like coffee cups, regular plastic, and styrofoam from the workspace. 

Personal Protection

• ESD-Safe Clothing:

  Wear specialized anti-static clothing, gloves, and footwear to prevent static discharge from your garments. 
• Body Grounding:

  Use heel or shoe straps to ground yourself when standing and working, in addition to wrist straps. 

Tools & Storage

• Antistatic Packaging:

  Store and transport electronic components in shielded bags, tubes, and conductive containers. 
• ESD-Safe Tools:

  Use anti-static or static-dissipative tools for working with sensitive components. 

Advanced Techniques 

• Ionizers:

  Employ ionizers or ionization blowers to neutralize static charges on objects and in the air where grounding is not feasible.
• ESD-Safe Materials:

  Select appropriate ESD-safe materials and equipment for your work environment.

  btw

  Also at work, ESD and the follow up problems, is a common problem;

  especially with young/new colleagues , every one kills one or many cpu's, 

  depends on the individual learning curve.

[Andrew Neil]

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@durna wrote:

it hangs at

GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;

Odd that it should hang there - that's just writing a constant value into a structure element. 

Shouldn't have any hardware dependency at all.

But, if it has been hit by an ESD, then that does put it firmly into undefined behaviour territory ...

[Imen.D]

Hello @durna ,

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@durna wrote:

- During debug, I noticed something strange: inside MX_GPIO_Init() the code enters, but it hangs at

GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;

---

Check the GPIO speed setting. Maybe the Low setting is insufficient for high-speed interfaces used. So, try update the Low GPIO speed to High or Very_High to match with the specific requirements of the peripheral.

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@durna wrote:

- What’s the recommended way to solve this and prevent it in the future (ESD protection, design practices, etc.)?

Many parameters come into account for ESD protecting, design practices. I advise you to refer to ST's guidelines AN1709, AN5612) for detailed ESD design, routing tips and recommendations improving the ESD protection.

[Imen.D]

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@durna wrote:

- What’s the recommended way to solve this and prevent it in the future (ESD protection, design practices, etc.)?

[Andrew Neil]

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@Imen.D wrote:

Maybe the Low setting is insufficient for high-speed interfaces used. 

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But the line shown is just putting the value into the config structure - there is no hardware involvement at this point.

[Danish1]

What were the few lines before the one that it hangs on? Was there an earlier call that used your initstructure?

What I’m wondering is that maybe you reconfigured a pin that is used by the debug interface so that the debugging session fails at that point. Sometimes, where peripherals are in different clock domains, it can take a few clock cycles for a write to actually hit the peripheral. So the debugging session might fail a few instructions after the command.

[Tesla DeLorean]

More likely you shorted something on a work surface, or broke some connections. Or introduced other higher voltages, or created high current paths across the STM32. It could be ESD, but the GPIO's have ESD protection diodes, I'd look for other causes first.

It's not clear from your presentation how exactly this was built / constructed. DuPont wires often don't connect or flex well.

Mount boards and devices such that they won't move about, or contact other surfaces. Use wire wrap or other connectors that cut / bite into the pin corners for a metal-to-metal interface.

[Andrew Neil]

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@Tesla DeLorean wrote:

It's not clear from your presentation how exactly this was built / constructed. Indeed.

@durna this is where posting some good, clear photographs of your system helps.

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@Tesla DeLorean wrote:

DuPont wires often don't connect or flex well.

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Indeed.

@durna solderless breadboards are also notorious for unreliable connections...

[Andrew Neil]

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@durna wrote:

- Power supply shows 0A current draw (normally it used to pull around ~0.3A).?

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How are you measuring that - what is the resolution of your measurement?

ie, Could it actually be 1mA, or whatever?

Have you checked the power supplies; eg, blown fuse, loose connection, something gone open-circuit ... ?

PS:

You also haven't said what board you are using.

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