Device will not enumerate

USB AVR Programmer and SPI interface. Adafruit's USBtinyISP.

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PyroAVR
 
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Device will not enumerate

Post by PyroAVR »

I recently had a need to use my USBTinyISP again, and upon trying to program a chip, found out that it does not work! I tried reseating my ATTiny chip, but unfortunately that did not help. No signs-of-life on either the computer end nor the device end are present, no lights come on and the device does not show up in the devices listings in Windows 7, MacOSX (Yosemite), or Linux (Debian 8). Is there any way I can check to see if the ATTiny onboard the programmer is okay? I wouldn't know what to look for...
Thank you very much!

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adafruit_support_rick
 
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Re: Device will not enumerate

Post by adafruit_support_rick »

If the USBtinyISP doesn't show up in any devices listings, then try some different USB cables. Otherwise there may be something wrong with the USBtiny itself. It used to work? Can you post pictures of both sides of it?

PyroAVR
 
Posts: 27
Joined: Sun Sep 02, 2012 6:11 pm

Re: Device will not enumerate

Post by PyroAVR »

I have tried several USB cables, machines, and ports, none of which have worked. I know the cables and ports are okay, I verified each with a known-good device (Blue USB Snowball microphone). I had to decrease the image quality in order to post, I hope it is still good enough for your needs.
Bottom of USBTinyISP 2.0
Bottom of USBTinyISP 2.0
bottom.jpg (542.58 KiB) Viewed 1215 times
Top of USBTinyISP 2.0
Top of USBTinyISP 2.0
Top.jpg (331.33 KiB) Viewed 1215 times

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adafruit_support_rick
 
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Re: Device will not enumerate

Post by adafruit_support_rick »

Some of those solders look like cold joints. The solder hasn't flowed completely over the pads. Retouch the solders where the solder hasn't flowed.
A good solder joint should look like this:
Image

PyroAVR
 
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Re: Device will not enumerate

Post by PyroAVR »

I reflowed every joint on the board with fresh solder, and voila! It works. Thank you very much for the help. Out of curiosity, however, why did it work fine before? No changes were made to the board between uses, and I kept it safely stored while I was not using it. What caused the joints to fail?

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adafruit_support_rick
 
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Re: Device will not enumerate

Post by adafruit_support_rick »

That's just the way cold joints behave.

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dmpyron
 
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Re: Device will not enumerate

Post by dmpyron »

Sometimes a cold joint will just fail due to movement and flexing. The board may seem rock solid to you, but those are 9.0 earthquakes to the joints.

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