On 12/23/14, 4:58 PM, "Chris Morgan" <chmor...@gmail.com> wrote:
>How is your esd protection designed at the usb connections, or are you >hitting the usb connectors right on the bbb? Would need a lot more >details about exactly how the system was being built and where you are >discharging to know what might be going on. I'm guessing your esd >protection may not be getting to a solid enough chassis ground close >enough to the connector that is being hit. Actually, from what I recall, the USB protection isn¹t in the right place. The correct layout is USB connector, ESD protection and then USB transceiver. However, in the BBB, the USB connector is connected to the USB transceiver and the ESD protection is on the other side of the USB connector. Granted, the distance is small and may even work correctly, but this layout doesn¹t follow good ESD layout principles. Regards, John > >Chris > > > >On Tue, Dec 23, 2014 at 6:40 AM, <lee.s...@bibby-scientific.com> wrote: >> Thanks for the prompt response Gerald. >> >> The beagle has been designed into a system which is in a plastic and >>metal >> enclosure. The only I/O it has to the outside (other than touchscreen) >>is 2 >> USB connections. >> >> These connections are what are prone to the 4kv ESD. A discharge on the >> shell of the USB connector causes the micro to reset. This occurs even >> though ESD suppression has been designed in at the USB connectors. >> >> The micro seems particularly prone to this phenomenon. ESD is an >>awkward >> problem to solve, there isn't one solution to fit all and things such as >> enclosure design can have an influence... >> >> On Monday, 22 December 2014 19:42:37 UTC, Gerald wrote: >>> >>> I am not sure what was used, other than putting it in a box or adding >>>ESD >>> protection devices on every point on the board likely to be touched by >>>a >>> person. >>> >>> The certification was done by a lab. You are welcome to download the >>>full >>> report from the WIKI. >>> >>> http://www.elinux.org/Beagleboard:BeagleBoneBlack >>> >>> Gerald >>> >>> >>> On Mon, Dec 22, 2014 at 7:57 AM, <lee....@bibby-scientific.com> wrote: >>>> >>>> Hi Guys, I am seeing the same issue as Richard above. Was a solution >>>> ever found for this ESD reset issue? >>>> >>>> In the past I have had some success on solving this issue on other >>>>micros >>>> by adding some capacitance on the micro's reset line to prevent the >>>>reset >>>> I/P bouncing when the ESD takes place, however looking at the BBB >>>> schematics, this is already included in the form of C24 being 1uF. >>>> >>>> Richard, did you find a solution to this? >>>> >>>> Gerald, I assume this family of processors must be used in many >>>> commercial products. Do you have an idea of what solutions were used >>>>to >>>> overcome this? >>>> >>>> Many thanks in advance. >>>> Lee. >>>> >>>> On Friday, 1 August 2014 18:57:39 UTC+1, Gerald wrote: >>>>> >>>>> CE testing that was does not cover ESD testing. This board has never >>>>> been tested for ESD. >>>>> >>>>> Gerald >>>>> >>>>> >>>>> >>>>> On Fri, Aug 1, 2014 at 12:21 PM, Richard Ketcham >>>>><rich.k...@gmail.com> >>>>> wrote: >>>>>> >>>>>> Hello, >>>>>> >>>>>> I'm interested in CE testing a device which includes the BBB. In >>>>>>order >>>>>> to determine if the device will pass, I've been shocking it with an >>>>>>ESD gun >>>>>> (both contact and discharge). I have been running into an issue >>>>>>where when >>>>>> I shock the ground plane with a 4kV contact discharge, the BBB >>>>>>Ethernet >>>>>> becomes unresponsive and does not recover until I cycle the power. >>>>>>I've >>>>>> tried this test with only the BBB and it reacts the same way. I see >>>>>>there's >>>>>> a CE certification which says it passes 4kV contact discharge, but >>>>>>I've been >>>>>> unable to replicate it. >>>>>> >>>>>> >>>>>> Are there caveats to the CE certification which the BBB has >>>>>>relating to >>>>>> ESD testing? >>>>>> Is this a self certification? >>>>>> Do you have any suggestions on how mitigate this problem? >>>>>> >>>>>> I will appreciate any information you can provide on this problem. >>>>>> Thanks, >>>>>> Rich >>>>>> >>>>>> -- >>>>>> For more options, visit http://beagleboard.org/discuss >>>>>> --- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "BeagleBoard" group. >>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>send >>>>>> an email to beagleboard...@googlegroups.com. >>>>>> For more options, visit https://groups.google.com/d/optout. >>>>> >>>>> >>>> -- >>>> For more options, visit http://beagleboard.org/discuss >>>> --- >>>> You received this message because you are subscribed to the Google >>>>Groups >>>> "BeagleBoard" group. >>>> To unsubscribe from this group and stop receiving emails from it, >>>>send an >>>> email to beagleboard...@googlegroups.com. >>>> For more options, visit https://groups.google.com/d/optout. >>> >>> >>> >>> >>> -- >>> Gerald >>> >>> ger...@beagleboard.org >>> http://beagleboard.org/ >>> http://circuitco.com/support/ >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google >>Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send >>an >> email to beagleboard+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. > >-- >For more options, visit http://beagleboard.org/discuss >--- >You received this message because you are subscribed to the Google Groups >"BeagleBoard" group. >To unsubscribe from this group and stop receiving emails from it, send an >email to beagleboard+unsubscr...@googlegroups.com. >For more options, visit https://groups.google.com/d/optout. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. 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