Page 136 - ARM Based Microcontroller Projects Using MBED

122 7. USING THE Mbed WITH SIMPLE PROJECTS

3, 8
(COM)

A B C D E F G DP

7 6 4 2 1 9 10 5
FIG. 7.68 SMA42056 7-Segment display pins.

7-Segment displays are available as either common anode or common cathode configura-
tions. In common anode displays all the anodes of the segments are connected together and
this common pin is connected to a power supply. A segment is turned ON when its
corresponding cathode pin is at logic 0. In a common cathode type display all the cathode
pins of the segments are connected together and this common pin is usually connected to
ground. A segment is turned ON when its corresponding anode pin is at logic 1. In addition
to displaying numeric values, a 7-segment LED can also display a decimal point.
In this project the SMA42056 type common cathode display is used. This is a 0.56in.
(14.20mm) red color display. Fig. 7.68 shows the connection diagram of this display. Pin 1
starts from the bottom left corner of the display. Bottom right-hand corner is pin 5, and
the top left corner is pin 10.

FIG. 7.69 Circuit diagram of the project.