5.9 Alphanumeric LEDs

Alphanumeric LED displays are used to display numerical as well as character data. These displays are similar to 7-segment LEDs, but are usually made up of 14-segments (plus a decimal point). Figure 5.16 shows a typical alphanumeric LED display. The segments are labelled ‘a’ to‘m’. As with the 7-segment displays, numbers and letters are displayed by turning the appropriate segments ON and OFF. The internal structure of a typical 14-segment common anode alphanumeric display is shown in Figure 5.17.

Figure 5.16 A typical 14-segment alphanumeric LED display

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Figure 5.17 Inside a 14-segment common anode alphanumeric LED display

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Figure 5.18 shows how the numbers, letters and various symbols can be displayed on 14-digit alphanumeric LED displays. Alphanumeric LEDs are connected to microcontrollers in the same as the way 7-segment displays are connected.

Figure 5.18 Displaying numbers, letters and symbols on alphanumeric displays

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A table similar to Table 5.3 can be constructed to determine how to display various characters. Table 5.4 shows what hexadecimal code to send to the port where the display is connected to, in order to display numbers ‘0’ to ‘9’ and letters ...

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