Feature: Power supply :5V-3V AVCC connect to 5V system power ASCL connect to 5V system SCL ASDA connect to 5V system SDA AGND connect to 5V system GND BVCC connect to 3V system power BSCL connect to 3V system SCL BSDA connect to 3V systems SDA BGND connect to 3V system GND