Author Topic: USB Dongle Died...  (Read 2663 times)

Offline DonFL

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USB Dongle Died...
« on: August 21, 2014, »
Grabbed one of two usb dongles last night to do some testing, and discovered, it has died.

No data output, no green LED. Red LED behaves as expected. Tried it on a different computer just to eliminate any driver/port issues, everything points to the dongle.

Being that I have a second one, I was able to swap 485, pic, and opto...nada...still dead. Those 3 socketed chips confirmed healthy.   

I have 5V out of the dc-dc converter. Voltages on the FET are the same on the two dongles.

The one thing I can't easily check is the usb interface, other than to compare pin by pin with the two dongles. Have not done that yet.

I use the two dongles just for controller testing and config, the display is all E1.31, so the issue, for now, is low priority. That said, having something sitting on the bench that doesn't work, and at least not knowing whats causing it, drives me nuts.. >:(

Any thoughts?


Offline tbone321

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Re: USB Dongle Died...
« Reply #1 on: August 21, 2014, »
It appears that there is NOTHING wrong with the two dongles.  If you are trying to use E1.31, then these dongle will not work.  A USB dongle, by definition, is a serial device and E1.31 is a DMX over Ethernet protocol and will be sending its output over your Ethernet jack, not your USB port.  You need to use the hardware manager (assuming Windows) and determine what serial port is being used by the driver and then configure whatever you are using for testing to use a serial connection with the port you determined to be used by the FTDI driver.  If your software configures by device name, the USB dongle acts like the Enttec Pro.  Don't use the Enttec open because that will not work either.
If at first you don't succeed,
your not cut out for sky diving

Offline DonFL

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Re: USB Dongle Died...
« Reply #2 on: August 21, 2014, »
Where did I say I was attempting to use the dongle for E131? Please see my comment in my original post...I use the two dongles just for controller testing and config,

I fully understand how the dongle works, what its used for, etc....I have two...one works..one has stopped working.



 
« Last Edit: August 21, 2014, by DonFL »

Offline tbone321

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Re: USB Dongle Died...
« Reply #3 on: August 21, 2014, »
Sorry for the error, I misread your first post.  In the past we had issues with USB  module but that was usually it not supplying power to the dongle but since you have the red LED lit, that does not appear to be the issue.  Like I said before, I would plug the unit into the PC and go into the hardware manager and see if it is recognised and if so, what serial port number is is being assigned to.  It can be and probably is different than the dongle that is working.  From what you are describing, the issue is that the PIC is either not getting any data or not processing it  and from your debugging, it appears that either the software you are using is not sending the data to the dongle (wrong port) or the USB module is not getting the data to the PIC. 

You may also want to take a good look at the board itself and make sure that all of the solder joints are good, especially around the crystal, the USB module and the RS485's.  Also take a look into the USB port and check for any damaged pins.
If at first you don't succeed,
your not cut out for sky diving

Offline DonFL

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Re: USB Dongle Died...
« Reply #4 on: August 21, 2014, »
I've verified it is recognized, and it is, as expected, a different com-port than the working device. All testing points to the dongle. 

It has been a working unit since I built it a year ago and all connections are solid. USB pins also are in good shape.

My leaning is toward the usb module being bad, no data passing thru to to the pic. If the crystal osc. did die I assume that would give me the same symptoms, but gut says that usb module is a much more likely culprit.

Offline tbone321

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Re: USB Dongle Died...
« Reply #5 on: August 21, 2014, »
While it is more than possible that the USB module is the problem, it seems unusual that it would be working enough to establish a connection with the PC.  One last thing that I would try is to delete the connection in the hardware manager after it is established and let it rebuild it.  That should eliminate any issues with a corrupt connection.  With the exception of checking the board for possible cold solder joints, you would really need a scope to trace the signal and see if it is actually getting to the PIC.  You can possibly check the crystal oscillator with a volt meter to see if it is putting out any signal but even there, a scope would be best.
If at first you don't succeed,
your not cut out for sky diving

Offline DonFL

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Re: USB Dongle Died...
« Reply #6 on: August 21, 2014, »
Yea, went thru the process of deleting the com port entry and letting it rebuild itself..nada.

Unfortunately, the closest thing I have to a legit scope is a 10+ year old parallax usb scope module...but should be enough to at least confirm existence of a good output from the oscillator.

So the typical failure mode for the usb module that's been experienced in the past has been for it to die completely, and hence, no red LED, no V+ anywhere on the board?


Offline tbone321

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Re: USB Dongle Died...
« Reply #7 on: August 21, 2014, »
Actually, the prior failed USB modules were not delivering power to the dongle PC board.  The module itself was working but the 5V power output was not putting out any power as indicated by no red LED lit either.  I believe that someone figured out a way to bypass the bad part of the module but it did require some skill in soldering and placement and that is not the issue here anyway since you do have the red LED illuminated.  The USB scope module should be more than enough to test both the oscillator and if a signal is being sent from the USB module and if so, trace it to where it stops.
If at first you don't succeed,
your not cut out for sky diving

Offline RJ

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Re: USB Dongle Died...
« Reply #8 on: August 21, 2014, »
Just put your digital volt meter across the output and ground of the oscillator and look for slightly less than 2.5volts. This will tell you if it is working.

It is normally other issues related to config or setup issues when it previously worked.

RJ
Innovation beats imitation - and it's more satisfying

Offline DonFL

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Re: USB Dongle Died...
« Reply #9 on: August 21, 2014, »
Seeing 5V at Vdd, and also...on the output.

Compared to the working device showing me 2.5 V as RJ mentions.

Looks like its time to add an oscillator module to the next mouser order.

Offline RJ

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Re: USB Dongle Died...
« Reply #10 on: August 22, 2014, »
glad it was that simple, The reason a little under 2.5 volts is because the osc cycles between 5v and 0v at the freqency it is designed for. But since it is 50% duty cycle. 1/2 the time on and 1/2 the time off, the meter sees about half the voltage so you can tell it is cycling on and off at a fast freq.

You may not wanted to know this but since I have had others ask it is a good place to post it.

RJ
Innovation beats imitation - and it's more satisfying

Offline DonFL

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Re: USB Dongle Died...
« Reply #11 on: August 22, 2014, »
Makes sense..and good information to have.

The quick check of the osc was the kind of insight I was looking for, appreciate the assistance.

Offline DonFL

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Re: USB Dongle Died...
« Reply #12 on: August 27, 2014, »
Osciillator replaced, issue resolved.