When we saw this chip, we quickly realized what an excellent add-on this would be. Using only two I2C pins, control 16 free-running PWM outputs! You can even stack up 62 shields to control up to 992 PWM outputs (which we would really like to see since it would be glorious and like 4 feet tall) Because I2C is a shared bus you can also connect other I2C devices and sensors to the SCL/SDA pins as long as their addresses don’t conflict (this shield has address 0x40)
There’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 Arduino 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 stack 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
We wrapped up this lovely chip into a shield with a couple nice extras
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 and red power-good LEDs
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
Stackable design. You&apos ll need to pick up stacking headers and right angle 3×4 headers in order to stack on top of this shield without the servo connections getting in the way.
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
A lot of extra space remaining? Let’s turn it into a prototyping area. You get a 5×20 proto area for any extra wiring you would like to add
This product comes with a fully tested and assembled shield as well as 4 pieces of 3×4 male straight header (for servo/LED plugs), a 2-pin terminal block (for power) and a stick of 0.1" header so you can plug into an Arduino. A little light soldering will be required to assemble and customize the board by attaching the desired headers but it is a 15 minute task that even a beginner can do. If you want to use right-angle 3×4 headers, we also carry a 4 pack in the shop. Servos and Arduino not included – but we do sell tons of different servos in the shop so pick up a few while you are here!
Check out our tutorial with Arduino and you can get our documented Arduino library which has both PWM and Servo examples!
Adafruit 16-Channel 12-bit PWM/Servo Shield – I2C interface (5:58)
Dimensions (no headers or terminal block) 2.1″ x 2.7″ x 0.1″ (54mm x 70mm x 3mm)
This board/chip uses I2C 7-bit addresses between 0x60-0x80, selectable with jumpers.