Adafruit 16-Channel 12-bit PWM/Servo Driver not detected
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Adafruit 16-Channel 12-bit PWM/Servo Driver not detected

by agodwin on Mon Oct 14, 2013 7:19 pm

I have this wiring setup: https://dl.dropboxusercontent.com/u/16683375/photo.JPG and I believe that it is correct, however when everything turns on (the power light on the servo driver is on on the servo driver as well) and I run the command "sudo i2cdetect -y 1" nothing shows up at 0x40. Is my wiring bad, or have I done something else wrong. I've followed the tutorial word for word.
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Re: Adafruit 16-Channel 12-bit PWM/Servo Driver not detected

by adafruit_support_mike on Tue Oct 15, 2013 12:10 am

Let's double-check the ribbon-cable connection. With that in place, take a voltage reading at the breakout's VCC pin. It should be 3.3v, obviously. Thing is, it's possible to connect the ribbon cable to the RasPi's GPIO header in a way that sends the signals to the wrong pins.

Also try `sudo i2cdetect -y 0`, just to see if anything shows up on the other I2C bus. There are some version issues there, too.
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Re: Adafruit 16-Channel 12-bit PWM/Servo Driver not detected

by agodwin on Tue Oct 15, 2013 8:37 pm

Sorry I took so long to reply. The multimeter says that it's 3.3 so the cable is correct. I've got a second revision pi, and tried both with no luck. The power light on the breakout lights up, but still nothing showing up on the pi. Unfortunately I've got no other i2c devices lying around, if you would like I can put some pictures of the breakout up to see if I'm missing anything blatant.
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Re: Adafruit 16-Channel 12-bit PWM/Servo Driver not detected

by adafruit_support_mike on Wed Oct 16, 2013 12:31 am

Do post a photo. The more information I have, the better I can sniff out trouble spots.
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Re: Adafruit 16-Channel 12-bit PWM/Servo Driver not detected

by agodwin on Wed Oct 16, 2013 7:49 pm

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Re: Adafruit 16-Channel 12-bit PWM/Servo Driver not detected

by agodwin on Thu Oct 17, 2013 7:14 pm

Would there be any way to test to see if it is the pi, or the specific pins without having another pi or i2c device lying around? I only have access to a multimeter right now.
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Re: Adafruit 16-Channel 12-bit PWM/Servo Driver not detected

by adafruit_support_mike on Fri Oct 18, 2013 1:01 am

I think we can solve this one just from the photos.

The pictures of the breakout show empty pads on both sides, but the photo of the connections showed pin header holding the breakout into the breadboard.

Am I right in guessing that you haven't soldered the pin header to the breakout, but instead were doing sort of a friction-fit by running the pins through the holes in the breakout and into the breadboard?

If so, that doesn't work. You need a solder joint to get a reliable connection between the breakout's pads and the pin header.
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