LED INTERFACE.ppt
Download as PPT, PDF0 likes373 views
This document discusses LED interfaces for displaying data using light emitting diodes (LEDs). It describes common cathode and common anode configurations for lighting individual LEDs based on bit patterns. A 7-segment LED display structure is shown along with its control byte format. Both parallel and serial interfaces are discussed, with the parallel interface connecting LED cathodes directly to microprocessor ports. The serial interface overcomes disadvantages of the parallel interface like requiring extra hardware, being simple in software, and using extra ports.
1 of 8
Download to read offline
More Related Content
What's hot (20)
Ad
Similar to LED INTERFACE.ppt (20)
Ad
LED INTERFACE.ppt
- 2. INTRODUCTION • Light Emitting Diodes (LEDs) are used to display limited data, results, etc., • The light emitting diode is a diode when conducts , emits light energy. The conduction starts when the anode is held at higher voltage than the cathode.
- 3. CONTD.. • In common cathode configuration whenever a bit is 1, the corresponding LED will glow. • In common anode configuration, a 0 in any bit position will make the corresponding LED glow. • So by loading a particular bit pattern in the port, the desired LED may be lighter. • The structured has eight segments marked a,b,c,d,e,f and h and it is very useful in the display of the numeric and alpha numeric data.
- 4. FIG : SEVEN SEGMENT LED AND ITS CONTROL BYTE FORMAT
- 6. CONTD.. • The parallel interface between the seven segments LED display is shown in the previous figure. • The anode of all LEDs are held permanently at +5v, whereas the cathodes are connected to the port bits. The Microprocessor will load any bit pattern in the out port. • The serial interface overcomes the below disadvantages. DISADVANTAGES : 1.) It requires extra hardware for interfacing. 2.) Software is very simple. 3.) It requires extra ports.
- 8. SEVEN SEGMENT LED DISPLAY INTERFACE TO THE 8085 USING THE 8255