Adafruit 16-channel PWM/Servo Shield with MEGA

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lbsa_drexel
 
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Adafruit 16-channel PWM/Servo Shield with MEGA

Post by lbsa_drexel »

Hello,

I was reading through the documentation (https://learn.adafruit.com/adafruit-16- ... onnections) for the servo shield to see if there was anything different I needed to do to use an Arduino Mega and read that "If you are using a Mega or ADK R2 or earlier, you will have to solder a wire from SCL to D21 and SDA to D20". I have tried that both ways that I could see but neither worked. Should I be trying something different?

Thanks,
Nick
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dastels
 
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Re: Adafruit 16-channel PWM/Servo Shield with MEGA

Post by dastels »

Looking at the previous paragraph:
For backwards compatibility with old Ardunos, SCL is connected to A5 and SDA is connected to A4. UNOs already have this connection on board. If you are using a Leonardo or Mega and want to use the A4/A5 pins, cut the traces on the top of the board between A4 and A5 and the two pins next to them labeled SCL/SDA.
I'm thinking that you will need to cut the traces between A4/A5 and SCL/SDA (on the shield) as well as connect SCL/SDA to the SCL/SDA (i.e. D21/D20) of the Mega.

Dave

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adafruit_support_bill
 
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Re: Adafruit 16-channel PWM/Servo Shield with MEGA

Post by adafruit_support_bill »

What vintage is your Mega? If your Mega is R3 or later, it will have SDA and SCL pins next to the AREF pin. The shield should work with no modifications on an R3 or later Mega.

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lbsa_drexel
 
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Re: Adafruit 16-channel PWM/Servo Shield with MEGA

Post by lbsa_drexel »

It says on the bottom that it is a Mega 2560 R3. So it should work plug and play like the Uno then?
The shield works with an Uno, I just wanted to use a Mega for the additional storage. Is there anything else I should try?

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Re: Adafruit 16-channel PWM/Servo Shield with MEGA

Post by adafruit_support_bill »

It says on the bottom that it is a Mega 2560 R3
It should be 'plug & play' then.

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Re: Adafruit 16-channel PWM/Servo Shield with MEGA

Post by lbsa_drexel »

Found the issue. For some reason the pins were not added to the SDA and SCL spots on the shield. But good to know that I do not need to make any jumpers now.

How come it worked without those pins when I was using the Uno?

Thanks for the help!
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Re: Adafruit 16-channel PWM/Servo Shield with MEGA

Post by adafruit_support_bill »

On the UNO, SDA and SCL are also connected to pins A4 and A5. On the Mega they are pins 20 and 21 which do not exist on standard sized shields.

Starting with R3, all full-size Arduino boards have duplicates of SDA and SCL next to the AREF pin for better compatibility with various shields.

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lbsa_drexel
 
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Re: Adafruit 16-channel PWM/Servo Shield with MEGA

Post by lbsa_drexel »

Good to know, thank you!

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