Two I2C Devices: Compatibility & Power of the MPU6050 and the PCA9685

Hello everyone!

I have merely joined discovered this field, only recently.
Hence, please pardon my ignorance :slight_smile:

I am working on a project that requires both the PCA9685 (12-bit 16-Channel PWM LED shield) and the MPU6050 (gyroscope/accelerometer) to connect to my Intel Edison Arduino Board through the I2C interface.

There are a couple o' things i am hoping you might be able to help me understand:

1- What is the best way to connect the devices?

The SCL, SDL lines are connected to the pins A5 and A4 respectively on the Edison Arduino Board.
According to what i have read (and correct me if i am misunderstanding) the way the I2C bus works allows for both devices to connect on the same as such:

However, the PCA9685 is made so that it is stack-able as you can see below:

So i am thinking of connecting my MPU and PCA as follows:

Would this be a better option?

2- What should i look for in order to determine whether the shields are compatible?

A friend of mine suggested the notion that if they both have different clock-rates i might have issues, now from what i know, if a chip is doing something then the clock line (SCL) would sent signals for the receiving board to wait, however, i can't help but wonder whether what my friend was skeptical about is a real issue. I have tried to look for information regarding this case, however, i had no luck.

could you please shed some light on how it would work

3- i have read somewhere that i might need some pull-up resistors for the devices, however, all their schematics have shown no resistors, so i assumed they have their own built-in solutions. I have also read somewhere that if i have multiple chips with integrated resistors that i must disable the resitors on all except one of them, is there any truth to that? how do i do that? where kind i find the information regarding whether there are any resistors or not?

Thank you very much :slight_smile:

Are the SDA and SCL on both sides connected to each other ? I think they are. I also think that there are already 10k pullup resistors on the Adafruit module.

Koepel:
Are the SDA and SCL on both sides connected to each other ? I think they are. I also think that there are already 10k pullup resistors on the Adafruit module.

Thank you for your response :slight_smile:

To tell you the truth, I do no know.
I mean i did search but the only document I found on the "chain-able" design was the following

And it does not specify the way the layot is connected.

I am planning under the assumption that they are indeed connected.

Does anyone have experience with this?