PCA9685 and two different I2C addresses?

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TConnect
 
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PCA9685 and two different I2C addresses?

Post by TConnect »

Dear,

using the Adafruit 16-Channel 12-bit PWM/Servo Driver - I2C interface - PCA9685 and scanning the I2C Bus with only connected this device I get two different addresses:

1. 0x40 (I found in your tutorials)
2. 0x70

Is it right?

Regards
Tim

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adafruit_support_bill
 
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Re: PCA9685 and two different I2C addresses?

Post by adafruit_support_bill »

Hmmm. Does the 0x70 go away when you disconnect the PWM driver?

0x70 is the default address for most of our LED matrix & 7-segment displays.

TConnect
 
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Re: PCA9685 and two different I2C addresses?

Post by TConnect »

Yes, there is no 0x70 address after taking away the PCA9685. Please take a look to the uploaded pictures. You will see the wiring without any servos connected. For testing I used both sides of the I2C Bus with the same result of displaying two addresses. Connecting a 5V external power supply and a servo motor at channel 0 using your example sketch "servo" works fine, because address 0x40 should be talkable.

I ordered some other components, for example the BMP180 pressure sensor or your Ultimate GPS Breakout v3 - all these components have their correct address and working at my arduino UNO R3.
Attachments
Running servo sketch successfully turns the servo
Running servo sketch successfully turns the servo
i2c_pca9685_servo_sketch_running.jpg (31.38 KiB) Viewed 4678 times
I2C Scanner running with PCA9685 connected
I2C Scanner running with PCA9685 connected
i2c_pca9685_scanner_sketch_running.jpg (28.48 KiB) Viewed 4678 times
Wiring the board
Wiring the board
i2c_pca9685_wiring.jpg (159.46 KiB) Viewed 4678 times

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adafruit_support_bill
 
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Re: PCA9685 and two different I2C addresses?

Post by adafruit_support_bill »

This is normal for this chip. In addition to the regular addressing which starts at 0x40, there is an "All Call" address at 0x70 for addressing all PCA9685 devices simultaneously. See section 7.1.2 of the datasheet: http://www.adafruit.com/datasheets/PCA9685.pdf

TConnect
 
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Re: PCA9685 and two different I2C addresses?

Post by TConnect »

Thanks for the information. In this way it is an interesting feature, I did not found because I have always my first one :-)
Regards Tim

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