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EB008 Quad 7-Segment Display Board
More information can be found here.
EB008 Quad 7-Segment Display Board Block Diagram
- Click EB008-30-1 for a datasheet.
- The male D-type connectors fit into the Female connectors of 2 of the ports of an upstream board.
- A 7-segment display is actually no more than:
- 7 LEDs with long shaped segments, placed in an '8' shape.
- 1 LED to indicate a decimal point.
- 7-segment displays can be:
- Common Cathode: where the Cathode of all of the LED's is common and the LEDs are lit by applying a positive voltage to the anode of the specific segment.
- Common Anode: where the Anode of all of the LEDs is common and the LEDs are lit by applying a negative voltage to the cathode of the specific segment.
- The Displays used on the EB008 E-block are of the Common Anode type.
- The tricky bit is that we do not have enough pins to drive all these LEDs (8 x 4 = 32 separate LEDs) by our controller. We will solve this by:
- Using the speed of the PICmicro.
- By driving pin 1-2-3 or 4 of J2 we determine which of the four 7-segment displays is active to receive data.
- Data is sent to the active display by the 8 data pins on J1.
- LEDs will emit light for a short time they have been turned off.
- So the trick is that you alternately activate each of the four 7 segment displays in turn, by making the appropriate anode via J2 high, and then send the data to each display by making the appropriate cathodes via J1 low
- If you only need one 7-segment display, then this can be activated permanently by putting a jumper next to the screw terminal on the board. This way only J1 is used to drive the left display and no multiplexing is needed.
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