Why mcu not reset on ESD test ?

[Mahendra Rana]

Posted on May 16, 2018 at 08:54

1. When I run system clock through HSE(8MHz/24MHz/25MHz) and PLLCLK (multiplier PLLN and divider PLLM & PLLR) than mcu not reset by ESD.

2. But when I run system clock directly through HSE(8MHz/24MHz/25MHz) than mcu get reset by ESD.

Can any one comment for my issue..

Note: this post was migrated and contained many threaded conversations, some content may be missing.

[Imen.D]

Posted on May 16, 2018 at 11:36

Hello

Rana.Mahendra_Singh

,

What is the Hardware board used ?

Best Regards

Imen

[Mahendra Rana]

Posted on May 16, 2018 at 12:47

Board is design by our own

[Tesla DeLorean]

Posted on May 16, 2018 at 13:55

>>Board is design by our own 

That's really not very illuminating.

The cue here is to provide more clear and specific information about the system that has a problem.

[Mahendra Rana]

Posted on May 16, 2018 at 14:01

That board is not any nucleo board. Its circuit and pcb was designed by our own.

[Tesla DeLorean]

Posted on May 16, 2018 at 14:06

Ok, but this provides zero insight, to social cue here is to provide sufficient detail that someone not inside your head can understand/see what is going on.

Present your question with enough context that it might be reviewed.

Not sure how HSE vs HSE+PLL would behave materially differently in the current context. Is a reset response to a large ESD not a likely/acceptable outcome?

[AvaTar]

Posted on May 16, 2018 at 14:08

The cue here is to provide more clear and specific information about the system that has a problem.

And what is the problem at all.

At least for burst/surge tests which are required for commercial devices here, the DUT is allowed to stop operating during the test. It only must not sustain permanent damage.

[Mahendra Rana]

Posted on May 16, 2018 at 14:26

My problem is :- During ESD test(contact discharge of 2KV/4KV and air discharge test upto 8KV) MCU got reset automatically when in code I run system clock through HSE ON(8/24/25 MHz) and PLL OFF. Means program counter also reset and starts from initial code.

But for same ESD test when I run system clock through HSE ON (8/24/25 MHz) and PLL also ON than MCU never resets. Why so?

Note :- Right now I am testing through electric lighter as not having ESD gun in my lab. But tested with ESD gun 

when in code I run system clock through HSE ON(8/24/25 MHz) and PLL OFF and MCU got reset automatically that time.

 

[Mahendra Rana]

Posted on May 16, 2018 at 14:29

No permanent damage only MCU reset and my HMI regain its same state so ESD test was passed in Type B category (IEC-61800-3 and IEC 61000-4-2).

[Mahendra Rana]

Posted on May 16, 2018 at 14:31

My problem is :- During ESD test(contact discharge of 2KV/4KV and air discharge test upto 8KV) MCU got reset automatically when in code I run system clock through HSE ON(8/24/25 MHz) and PLL OFF. Means program counter also reset and starts from initial code.

But for same ESD test when I run system clock through HSE ON (8/24/25 MHz) and PLL also ON than MCU never resets. Why so?

Note :- Right now I am testing through electric lighter as not having ESD gun in my lab.

But tested with ESD gun 

when in code I run system clock through HSE ON(8/24/25 MHz) and PLL OFF and MCU got reset automatically that time.

 

No permanent damage only MCU reset and my HMI regain its same state so ESD test was passed in Type B category (as per IEC-61800-3 and IEC 61000-4-2 standards).