Display is common cathode. Pinout of Display:
D2 H is hooked up to the colon.
HOW TO DISPLAY NUMBERS: To select which digit you want, you set the digit's pin LOW. (e.g. If I want to use Digit 1, I make D1 LOW.) Then, while my digit is selected, I turn on a segment. Then that segment will light up on the selected digit. To light up multiple digits, I cycle through the digits and segments really fast. (e.g. If I want to display the number 42, I would select D1 and turn on the first segment in the number 4, then turn off that one, then turn on the next segment in the number 4. Now 4 is finished, so I deselect that digit then select the next digit (D2) and then do the same for the number 2.) MAKE SURE TO USE 10K OHM RESISTORS FOR DIGIT PINS!
![](http://www.weebly.com/uploads/1/5/0/3/15036700/332264_orig.jpeg)
HOW TO DISPLAY NUMBERS: To select which digit you want, you set the digit's pin LOW. (e.g. If I want to use Digit 1, I make D1 LOW.) Then, while my digit is selected, I turn on a segment. Then that segment will light up on the selected digit. To light up multiple digits, I cycle through the digits and segments really fast. (e.g. If I want to display the number 42, I would select D1 and turn on the first segment in the number 4, then turn off that one, then turn on the next segment in the number 4. Now 4 is finished, so I deselect that digit then select the next digit (D2) and then do the same for the number 2.) MAKE SURE TO USE 10K OHM RESISTORS FOR DIGIT PINS!