PCA9685 16-Channel 12-Bit PWM Servo Driver can help a lot when there are insufficient PWM output pins for the MCU in your project. 

 

The only condition is that the main control chip supports I2C communication, which means enabling the communication between the chip and PCA9685, so as to control multiple servos simultaneously. 

 

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Datasheet

Features :

• Contain an I2C-controlled PWM driver with a built-in clock. It means, unlike the TLC5940 family, you do not need to continuously send it signals tying up your microcontroller; it's completely free running! 
• 5V compliant, which means you can control it from a 3.3V microcontroller and still safely drive up to 6V outputs (this is good when you want to control white or blue LEDs with 3.4+ forward voltages) 
• Support using only two pins to control 16 free-running PWM outputs – you can even chain up 62 breakouts to control up to 992 PWM outputs
• 3 pin connectors in groups of 4, so you can plug in 16 servos at one time (Servo plugs are slightly wider than 0.1" so you can only stack 4 next to each other on 0.1" header
• 12-bit resolution for each output - for servos, that means about 4us resolution at 60Hz update rate

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