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Author Topic: Tombstones on Due  (Read 1345 times)
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On 2 of 4 Due's I had Tombstones (wrong soldered SMD-Devices, stand up instead lie flat), if your Due has a strange behavior take a look.

Btw, why is the wire an sinuous line like a snake, shall it be an inductance ?


* Tombstone-Due.jpg (58.05 KB, 429x416 - viewed 43 times.)
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Greenville, IL
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Btw, why is the wire an sinuous line like a snake, shall it be an inductance ?


 Just a guess, maybe it is to help make the traces the same overall length. I have read that with high speed devices that trace length is important.
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Trace length is important only at very high frequencies. The Due is not in that category. Serpentine traces are used to help anchor the copper to the board. Line straight lines tend to lift if they experience a temperature change. Think of it as expansion joints.
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On 2 of 4 Due's I had Tombstones (wrong soldered SMD-Devices, stand up instead lie flat), if your Due has a strange behavior take a look.

well that never should have made it to you. Somewhere in QA it should have been rejected. That's caused by poor paste distribution, improperly placed component or some similar problem in the manufacturing process.
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nr Bundaberg, Australia
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it is to help make the traces the same overall length. I have read that with high speed devices that trace length is important.
Correct. In general the Due does not have any high-speed signals but the USB D- and D+ might be an exception, which is what you are seeing here.

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Rob
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Rob Gray aka the GRAYnomad www.robgray.com

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 Cool! I got one right!

 Thanks for your input Graynomad. I still think one of your designs for the Atmel Arm chip would be great to see!
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nr Bundaberg, Australia
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It's in the works, we're going over the mechanical and electrical design as we speak.

Just to give you a hint, fits a standard enclosure, support for EMAC (RMII ethernet), I2S (codecs), HSMCI (fast SD cards), 24 PWM, 8 native analog inputs, 8-bit 8MB external memory, 2x CAN, up to 8 addressable daughter boards with quasi-vectored interrupts, control over various power options, and hopefully reasonable legacy shield support.

Some of this is a bit above my pay grade but the basic design is done and it looks doable.

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Rob
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Rob Gray aka the GRAYnomad www.robgray.com

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  Nice to know your board still has a chance to live! Sounds like it is going to have nearly anything a person could possibly want!
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nr Bundaberg, Australia
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Watch this space. We should shave some nice features.

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Rob
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Rob Gray aka the GRAYnomad www.robgray.com

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