Author Topic: Struggling with project. Not sure what to do.  (Read 2970 times)

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Offline stmdude

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Re: Struggling with project. Not sure what to do.
« Reply #25 on: September 06, 2017, 02:39:17 am »
I have cut the traces just above the USB connector going to the FFC connector. Did not improve anything.

Ill look into differential signals. I did keep the routes the same on my other board, but was told by a few people that it does not matter at these lengths.

There's a few things that matter _less_ when you have a small board and "only" run 12Mbps, such as impedance matching and to a certain extent, skew.  However, you absolutely need to route it as a differential signal. D+ and D- needs to run parallel to each other the entire way with a fixed distance between them. Use as few vias as possible, but if you need to use them, always use them in pairs. Everything one line does, the other one needs to do.
 

Online RoGeorge

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Re: Struggling with project. Not sure what to do.
« Reply #26 on: September 06, 2017, 02:56:59 am »
In my opinion, if the extra ramification traces were already cut, then it's probably the FTDI chip.
If the D+ and D- are not reversed, then it must be either a defective FTDI, or a fake FTDI that was bricked by the windows drivers.

Offline dmills

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Re: Struggling with project. Not sure what to do.
« Reply #27 on: September 06, 2017, 03:10:40 am »
Concur, 12Mb/s USB is not usually all that delicate.

Ground pours are better then thin traces, do them on BOTH sides of the board and via stitch extensively, still much worse then a nice solid plane, but better then what you have, and as said, think about current loops, they are key to anything high speed.

Vias are cheap, keep adding stitching until your board vendor starts putting the cost up because of too many vias,then back off just a little....

I would be very surprised if CircuitMaker cannot do at least 4 layers, that would make it basically useless for anything faster then audio.

Regards, Dan.
 

Offline stmdude

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Re: Struggling with project. Not sure what to do.
« Reply #28 on: September 06, 2017, 03:31:11 am »
Vias are cheap, keep adding stitching until your board vendor starts putting the cost up because of too many vias,then back off just a little....

Words to live by.  ;D
 

Offline Jackster

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Re: Struggling with project. Not sure what to do.
« Reply #29 on: September 07, 2017, 04:19:36 am »
This looking better? No forks. Just via the FFC.
Bottom layer I covered with a GND polygon that auto fills. Removed most of the GND routes so that the polygon connects most of the GND components, vias etc.





[edit]
Not put a load of vias in yet. Working on USB first.
« Last Edit: September 07, 2017, 04:25:42 am by Jackster »
 


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