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I2C & PCA9685 : (
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

I2C & PCA9685 : (

by servin on Tue Feb 13, 2018 10:00 am

Hello,
Grrr. I just can't get SDA/SCL to drive servos via the PCA9685 PWM breakout, using the 'servo' example <Adafruit_PWMServoDriver.h> ...
On both UNO & MetroMini, I can get a 128x32 I2C OLED to work fine, so I think I know that SDA & SCL work ok;
and servos work fine when driven with pin-direct PWM, i.e. the Servo 'sweep' example code, so I think I know the servo pinouts are clear...

But no motion from 'servo' code, using pwm.setPWM()... :(
Servos do step in one direction several steps each time I connect/reconnect power, but that's all...
I've confirmed grounds, tried various combinatorial variations on the 3 servo leads, varied min & max pulse-width, etc...

I dont know how to diagnose / systematically debug any further - its a bit of a black box (without a scope, or analyzer, etc...)
Any suggestions?
TIA

Stephen E
attached photo (barely) shows metro-mini & breakout wiring.
IMG_0819.jpg
IMG_0819.jpg (176.53 KiB) Viewed 246 times

servin
 
Posts: 6
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Re: I2C & PCA9685 : (

by adafruit_support_bill on Tue Feb 13, 2018 10:12 am

Please post a photo that clearly shows your connections. We need to be able to see both ends of the wires and what pins they are connected to.

Also, what are you using for servo power? The green power LED does not appear to be lit.

adafruit_support_bill
 
Posts: 68484
Joined: Sat Feb 07, 2009 10:11 am

Re: I2C & PCA9685 : (

by servin on Thu Feb 15, 2018 10:39 pm

Hi support_bill;
I've posted a few more photos here. I have a separate 5v power supply for the servos.
I plugged it back in for the latest photo, so the light is green.
IMG_0821.JPG
IMG_0821.JPG (452.77 KiB) Viewed 203 times

IMG_0827.jpg
IMG_0827.jpg (170.35 KiB) Viewed 203 times


N.B. Noticing a reply in a recentI2C servo driver thread on this forum ("Trouble with my second..." by grizzlyprototypes),
I tried the 'I2CScanner' code. All I get is "No I2C devices found", with the 9685 plugged in on SDA/SCL.
Plugging in my 128x32 OLED display, into the same SDA/SCL pins, I get "Device found at address 0x3C", as expected...
Screen Shot 2018-02-15 at 9.34.21 PM.png
Screen Shot 2018-02-15 at 9.34.21 PM.png (622.28 KiB) Viewed 203 times


Perhaps the 9685 isnt up to snuff. Might I try a replacement?
Pls advise,

Thx
Stephen E

servin
 
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Joined: Tue May 16, 2017 9:00 am

Re: I2C & PCA9685 : (

by adafruit_support_bill on Fri Feb 16, 2018 6:49 am

OK. That all looks good. We can try replacing it. Please contact support@adafruit.com with a link to this thread.

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Re: I2C & PCA9685 : (

by servin on Thu Feb 22, 2018 9:49 pm

Replacement board received promptly; Thanks : )
Problem solved; 2x Thanks !!

You guys are the best.
SErvin
Attachments
IMG_0805.jpg
kermit the superbowl frog (lights up, arms up, & croaks on hometeam touchdown !)
IMG_0805.jpg (190.03 KiB) Viewed 129 times

servin
 
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Re: I2C & PCA9685 : (

by adafruit_support_bill on Fri Feb 23, 2018 6:44 am

Nice looking project! Thanks for the photo.

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Joined: Sat Feb 07, 2009 10:11 am

Please be positive and constructive with your questions and comments.