Power Pins

• VIN - The power pin. To power the board, give it the same power as the logic level of your microcontroller - e.g. for a 5V microcontroller like Arduino, use 5V.
  
• VIO - Output from the on-chip power supply regulator for the digital power supply.
• GND - Common ground for power and logic.

Terminal Block Pins

At the top edge of the board is a 6 pin terminal block. This block has inputs for channels A and B on the HX711 (A+, A- and B+, B-) and power and ground connections for a strain gauge (E+ and E-).

• A+ - Channel A positive input. You'll connect the green wire on your strain gauge to this block.
• A- - Channel A negative input. You'll connect the white wire on your strain gauge to this block.
• B+ - Channel B positive input. This is a secondary input for the HX711.
• B- - Channel B negative input. This is a secondary input for the HX711.
• E+ - Connected to the analog power output. You'll connect the red wire on your strain gauge to this block.
• E- - Connected to common ground. You'll connect the black wire on your strain gauge to this block.

HX711 Logic Pins

The HX711 uses "pseudo-SPI" to communicate. You can use any two digital pins on your microcontroller for clock and data.

• SCK - Serial clock input.
• DATA - Serial data output.
• RATE - Output data rate control. If this pin is low, the data rate is 10 SPS and if the pin is high, the data rate is 80 SPS.

Rate Selection Switch

• RATE Switch - On the right side of the board is a slide switch. It is labeled Rate on the board silk. This switch selects the data rate for the HX711. If the switch selects H, then the data rate is 80 SPS. If the switch selects L, then the data rate is 10 SPS.

VIO Jumper

On the back of the board is an open solder jumper. It is outlined in white on the board silk. If you solder this jumper closed, it will connect VIN to VIO, which is the digital power supply (DVDD) pin on the HX711.