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This module is a breakout board for the NXP PCA9685 16 channel PWM controller. It features 16 fully programmable PWM outputs with a 12bit resolution giving a total of 4096 programmable steps with a duty cycle being adjustable from 0% to 100%. Additionally, the output frequency of all 16 channels can be programmed from 24Hz to 1526Hz.
Intended for controlling the brightness of multiple LEDs, the programmability of its PWM outputs means that it can also be configured for producing PWM signals compatible with driving standard servos.
In fact, this module has been designed with this purpose in mind with 16 sets of headers that allow for any servo with a standard header to be directly plugged into the module. A screw terminal block provides a means of powering the attached servos from an external 5V PSU and so the number of servos you can drive from your microcontroller and so is not limited by the microcontrollers own power supply.
The module also includes an I2C header with 10K pullup resistors and so only requires two data pins (SDA & SCL) to control the module. Solderable pads on the module provide a means of changing the default I2C address (0x40) to one of 62 options, meaning more than one module can be connected to the same I2C bus.
A wide operating range of 2.3V to 5.5V allows the module to be powered from a range of power supplies and when powered from a 3.3V supply is safe to interface to a Raspberry Pi or 3.3V or any other non 5V tolerant microcontrollers.
- It's an i2c-controlled PWM driver with a built in clock. That means that, unlike the TLC5940 family, you do not need to continuously send it signal tying up your microcontroller, its completely free running!
- It is 5V compliant, which means you can control it from a 3.3V microcontroller and still safely drive up to 6V outputs (this is good for when you want to control white or blue LEDs with 3.4+ forward voltages)
- 6 address select pins so you can wire up to 62 of these on a single i2c bus, a total of 992 outputs - that's a lot of servos or LEDs
- Adjustable frequency PWM up to about 1.6 KHz
- 12-bit resolution for each output - for servos, that means about 4us resolution at 60Hz update rate
- Configurable push-pull or open-drain output
- Output enable pin to quickly disable all the outputs
- Terminal block for power input (or you can use the 0.1" breakouts on the side)
- Reverse polarity protection on the terminal block input
- Green power-good LED
- 3 pin connectors in groups of 4 so you can plug in 16 servos at once (Servo plugs are slightly wider than 0.1" so you can only stack 4 next to each other on 0.1" header
- "Chain-able" design
- A spot to place a big capacitor on the V+ line (in case you need it)
- 220 ohm series resistors on all the output lines to protect them, and to make driving LEDs trivial
- Solder jumpers for the 6 address select pins
PCA9685
