An application of 8085 register interfacing with LED
Download as PPTX, PDF5 likes12,108 views
The document discusses interfacing LEDs and seven-segment displays with the 8085 microprocessor, covering input/output concepts, types of connections, and binary addressing. It explains common cathode and common anode configurations, illustrating how to display digits using a seven-segment display. Additionally, it includes an assembly language routine to control an 8-digit seven-segment LED display to show a message.
![Presented By:-
Taha Malampattiwala 140050107052
CSE 1 [Batch 4]](https://image.slidesharecdn.com/anapplicationof8085registerinterfacingwithlcd-160809072513/85/An-application-of-8085-register-interfacing-with-LED-2-320.jpg)
An application of 8085 register interfacing with LED
- 1. AN APPLICATION OF 8085 REGISTER INTERFACING WITH LED
- 2. Presented By:- Taha Malampattiwala 140050107052 CSE 1 [Batch 4]
- 3. BASIC I/O CONCEPTS • Peripherals such as LEDs and keypads are essential components of microcontroller-based systems • Input devices • Provide digital information to an MPU • Examples: switch, keyboard, scanner, and digital camera • Output devices • Receive digital information from an MPU • Examples: LED, seven-segment display, LCD, and printer • Devices are interfaced to an MPU using I/O ports
- 5. INTERFACING AND ADDRESSING • I/O ports • Buffers and latches on the MCU chip • Assigned binary addresses by decoding the address bus • Generally bidirectional • Internal data direction registers • To read binary data from an input peripheral • MPU places the address of an input port on the address bus • Enables the input port by asserting the RD signal • Reads data using the data bus • To write binary data to an output peripheral • MPU places the address of an output port on the address bus • Places data on data bus • Asserts the WR signal to enable the output port
- 6. INTERFACING OUTPUT PERIPHERALS • Commonly used output peripherals in embedded systems • LEDs • Seven-Segment Displays • LCDs • Two ways of connecting LEDs to I/O ports • Common Cathode • LED cathodes are grounded • Logic 1 from the I/O port turns on the LEDs • Current is supplied by the I/O port called current sourcing • Common Anode • LED anodes are connected to the power supply • Logic 0 from the I/O port turns on the LEDs • Current is received by the chip called current sinking
- 8. SEVEN-SEGMENT DISPLAY • Seven-segment Displays • Used to display BCD digits • 0 thru 9 • A group of 7 LEDs physically mounted in the shape of the number eight • Plus a decimal point • Each LED is called a segment • ‘a’ through ‘g’ • Two types • Common anode • Common cathode
- 9. SEVEN-SEGMENT DISPLAY • Common Anode • All anodes are connected together to a power supply • Cathodes are connected to data lines • Logic 0 turns on a segment • Example: To display the digit 1 • All segments except b and c should be off • 11111001 = F9H 9 330_09 Common Anode
- 10. SEVEN-SEGMENT DISPLAY • Common Cathode • All cathodes are connected together to ground • Anodes are connected to data lines • Logic 1 turns on a segment • Example: To display digit 1 • All segments except b and c should be off • 00000110 = 06H 330_09
- 11. INTERFACE AN 8-DIGIT 7 SEGMENT LED DISPLAY TO THE 8085 MICROPROCESSOR SYSTEM AND WRITE AN 8085 ASSEMBLY LANGUAGE ROUTINE TO DISPLAY MESSAGE ON THE DISPLAY.
- 12. 1. MVI A, 80H : Load control word in AL 2. OUT CR : Load control word in CR 3. MVI B, 08H : load count 4. MVI C, 7FH : load select pattern 5. LXI H, 6000B : starting address of message 6. DISP 1: MOV A, C : select digit 7. OUT PB 8. MOV A, M : get data 9. OUT PA : display data 10. CALL DELAY : wait for some time 11. DISP 1: MOV A, C 12. RRC 13. MOV C, A : adjust selection pattern 14. INX H 15. DCR B : Decrement count 16. JNZ DISP 1 : repeat 8 times 17. RET 18. Delay: LXI D, Count : Delay Subroutine 19. Back: DCX D 20. MOV A, D 21. ORA E 22. JNZ Back 23. RET