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• What is 7-SEGMENT DISPLAY (SSD)? – A seven-segment display is a form of electronic display device for displaying decimal numbers (and some alphabets too). SSD may use a liquid crystal display (LCD), a light-emitting diode (LED) for each segment, or other light-generating or controlling techniques such as cold cathode gas discharge, vacuum fluorescent, incandescent filaments, and other.

•  Types of SSD– There are mainly two types of SSD available. In a simple LED package, typically all of the cathodes (negative terminals) or all of the anodes (positive terminals) of the segment LEDs are connected and brought out to a common pin; this is referred to as a “common cathode” or “common anode” device. Besides this, there is also a SSD multiplexer is used called 2 digit, 3 digit and so on as you can see on photos.

• Operation – In a simple LED package common cathode SSD, there has 10 pin out of which 2 is ground and rest is LED segments . Particular LED segment is glow(ON) by giving logic ‘1’ to it and rests at logic ‘0’.

So we need to program this 8 pin to display our number on SSD. In following table, we convert this 8 pin’s 8 bit binary data into hex code and shows the hex code of displaying digits below.

 Digit Hex code A B C D E F G 0 0x3F 1 1 1 1 1 1 0 1 0x06 0 1 1 0 0 0 0 2 0x5B 1 1 0 1 1 0 1 3 0x4F 1 1 1 1 0 0 1 4 0x66 0 1 1 0 0 1 1 5 0x6D 1 0 1 1 0 1 1 6 0x7D 1 0 1 1 1 1 1 7 0x07 1 1 1 0 0 0 0 8 0x7F 1 1 1 1 1 1 1 9 0x6F 1 1 1 1 0 1 1

• Applications-  SSD is widely use in digital clocks, pricing menu at petrol pump, in metros and electronics meters as shown above.

### 1. Program Of 0 To 9 Counter On Cathode  7  segment display  interfacing with ARM7  (LPC2148)

#### PROTEUS File for SIMULATION(Password Of RAR file is :-firmcodes.com)

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### 2. Program Of 000 To 999 Counter On Common Cathode  7  segment display  interfacing with ARM7 (LPC2148)

#### PROTEUS File for SIMULATION(Password Of RAR file is :-firmcodes.com)

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