Green light won't work

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

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rocifier
 
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Green light won't work

Post by rocifier »

Hi, I've assembled the USBtinyISPv2 kit, but the green light doesn't work when I connect it to my PC (of course Windows 7 or Linux doesn't matter, since it doesn't get to the device ID part). I've not once had it work, and I checked over all the parts and the direction they are placed and all my solder joints. I took care with anti static. Everything seems good. Except, I had to use resistors lower than 27 ohms for R1 and R2 because that's all I had - I lost the original ones. Does this matter? It seems to only provide current protection from my rookie understanding of the schematic (please don't just bash on me for using the wrong value components, but instead explain why they wouldn't work if this is the problem).

What can I do next to debug the problem? I have a multimeter.

FIRST: Are you using a USBtiny from a kit or from DIY? Adafruit KIT v2
SECOND: What OS and computer are you using? Windows 7
THIRD: Which programming software are you using, and what chip? avrdude, atmega8 but haven't connected the chip circuit yet
FOURTH: Did the USBtinyISP ever work (even once) or is it your first time trying to talk to a chip? First time
FIFTH: Post screenshots (NOT copy&paste) of what is happening - below
SIXTH: Post clear, in-focus, not-blurry, easy to see photos of the top and bottom of the kit. If the photos are blurry, unfocused, and difficult to see they will only make it harder to debug what is going on - below:

Image
Image

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adafruit_support_rick
 
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Re: Green light won't work

Post by adafruit_support_rick »

rocifier wrote:What can I do next to debug the problem? I have a multimeter.
From what I can see, your build looks good. Nice soldering.

One thing to try is to use your multimeter to probe the green LED leads - see if you're actually getting voltage there. The LED might be bad.

What kind of computer are you using? There's a known quick with recent Macs:
https://learn.adafruit.com/usbtinyisp/u ... cator-leds

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rocifier
 
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Re: Green light won't work

Post by rocifier »

The voltage seems to go up and down on the pins perhaps every second. it goes from 0v to about 1.2v (though might be wrong as my multimeter seems slow). is it supposed to be blinking? if the LED simply were in fact bad, why does nothing happen on the computer end? Im not using a mac just a desktop pc.

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rocifier
 
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Re: Green light won't work

Post by rocifier »

I measured it again and this time I get -0.7V one way and in the other polarity it's slowly increasing voltage from 0V to about 250mV and it then hovers around there fluctuating.

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Re: Green light won't work

Post by adafruit_support_rick »

Hmmm. Can you try some different USB cables and different USB ports? Try connecting through a self-powered hub if you have one. The green LED indicates that the USBtiny has a USB connection.

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rocifier
 
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Re: Green light won't work

Post by rocifier »

I tried two different cables, one of them near new but tested with a usb printer. I tried a number of usb ports. I don't have a self powered hub but I did try a regular one. None of these had any success. In all cases I was able to read 5V on different parts of the board.

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Re: Green light won't work

Post by rocifier »

Do you think it might be a bad chip? I read a couple of other people on here had the same problem and upon receiving new ICs their problem was solved

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Re: Green light won't work

Post by rocifier »

I think I'm going to give up and get a different programmer. Thanks for the help anyway.

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Re: Green light won't work

Post by adafruit_support_rick »

I think is probably is a bad chip. Please email [email protected] with a link to this thread for a replacement USBTinyISP

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