| | | clock stops!
Hello:
I have a problem with lpc764 microcontroller in an ESD test.
Sometimes, when we apply high voltage discharge, the xtal stop and the program donīt run.
Itīs very strange because the microcontroler donīt able to start the oscilator.
the xtal circuit is 8Mhz xtal and 33pF capacitors.
After we apply again the supply to the uC it start running normally.
someone have any suggestion to protect the circuit and avoid this type of failure?
Thank you
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26-7-2005 2:06
Views: 1627 |
Alcad |
| | | RE: clock stops!
Hi,
Quite a problem to resolve.
You haven''t provided much information, for example:
- is this an EMC compatibility test?
- are you expecting such events in the normal life of the product?
- how is the discharge applied?
From your description it appears that no permanent damage is done to the device as the removal and reapplication of power restarts it.
I would look at the earth and supply routing on your PCB.
I would also look at whether you need double sided PCB, especially if it will be normal for
... more (see whole posting)
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26-7-2005 16:41
Views: 1644 |
Support |
| * | | RE: clock stops!
Hi,
We have had similar problems in a product using the 76x family, but the affected circuitry was in the associated real-time clock. The PCB was in a plastic case and we found that we could stop the RTC 32 kHz oscillator by rubbing the case with a dry cloth! It was also similarly affected by a nearby high-voltage discharge.
The cure for us was a small earthed shield soldered to the PCB that covered the crystal.
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6-8-2005 23:50
Views: 1551 |
ParticleMan |
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