AM335x ESD reset issue

Kevin Chen

Intellectual 390 points

Other Parts Discussed in Thread: AM3352

Hi,

The AM3352 will reset after ESD shock In the ESD test. The ESD shock level is 22KV.

Any interface or GPIO (except PORZ, NRESETIN_OUT&RTC_PORZ)will cause the AM3352 reset after ESD shock?

Best Regards,

Kevin

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

There may be a lot of reasons for this to happen - from bad PCB layout to inadequate ESD protection. it's impossible to say what is the reason based on the information you have posted. Note that AM335x I/Os are not fail-safe and external protection should be provided to ensure they are kept within datasheet specs.

0 Kevin Chen over 8 years ago in reply to Biser Gatchev-XID

Intellectual 390 points

Hi Biser,
We didn't find the reason cause this issue. And you mean the AM3352 I/Os and interface(like touch screen & LCD)will also cause the reset while they are out of the Maximum Ratings range?
Best Regards,
Kevin

0 Biser Gatchev-XID over 8 years ago in reply to Kevin Chen

TI__Guru**** 393215 points

Yes, it's possible.

0 Kevin Chen over 8 years ago

Intellectual 390 points

Hi,

The AM3352 will reset after ESD shock. We check the PRM_RSTST Register value is 00 0010 0001. What's the meaning of this value? The Global external warm reset and Power-on reset have occurred at same time? The PWRONRSTn pin and WARMRSTn pin is asserted at same time?

Best Regards,
Kevin

0 Kevin Chen over 8 years ago in reply to Biser Gatchev-XID

Intellectual 390 points

Hi Biser,
The new poster is different with this one. We check the PRM_RSTST Register value, and The value is 00 0010 0001. It's has two reset sources in one reset action. Is it means two reset sources have occured at same time?

Best Regards,
Kevin

0 Biser Gatchev-XID over 8 years ago in reply to Kevin Chen

TI__Guru**** 393215 points

You should check both reset lines for spikes during the ESD discharge.

0 Kevin Chen over 8 years ago in reply to Biser Gatchev-XID

Intellectual 390 points

Hi Biser,
I think use the scope to check the spikes during the ESD discharge will change the path of the ESD discharge. The result won't be true.

Best Regards,
Kevin

0 Biser Gatchev-XID over 8 years ago in reply to Kevin Chen

TI__Guru**** 393215 points

Try placing ESD protection on these lines.

0 Kevin Chen over 8 years ago in reply to Biser Gatchev-XID

Intellectual 390 points

Hi Biser,
I think it should be check the reset reason before add ESD protection. So i want to make sure it's the PWRONRSTn pin and WARMRSTn pin are disturbed or other IOs are disturbed by ESD shock? This is the question that i asked yesterday. Today i place a 0.1uF cap near the reset pin to help avoid ESD-induced resets, it doesn't work.

Best Regards,
Kevin

0 Biser Gatchev-XID over 8 years ago in reply to Kevin Chen

TI__Guru**** 393215 points

An ESD discharge can propagate through any conductive part. Usually it follows the lowest impedance path. It can propagate through I/O pins, through power supplies, through GND. A capacitor will not help here, you need ESD clamps.

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AM335x ESD reset issue