Dot Matrix LED Interfacing using 8255 PPI
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The document describes an experiment interfacing an 8x8 dot matrix LED display to an 8255 PPI (Programmable Peripheral Interface) chip in an 8086 microprocessor environment. It explains that the LED display has rows and columns that can be controlled individually to light different LEDs. The 8255 PPI chip is used to control the rows and columns via its ports A, B, and C. The document provides the port addresses for the 8255 and explains how to set the control word to configure the ports for output to control the LED display. It then describes several experiments conducted like scrolling text and the letter "A" across the display in different directions.
Dot Matrix LED Interfacing using 8255 PPI
- 1. Department of Electrical and Electronic Engineering Khulna University of Engineering & Technology Khulna-9203 Course code : EE 3214 Sessional on Microprocessors, Micro-controllers and Peripherals Presented By Amit Kumer Podder Experiment No. 07
- 2. Dot Matrix LED Interface Using 8255 PPI in 8086 Microprocessor Environment Experiment Name
- 3. The Dot Matrix LED Display An LED Matrix consists of an array of LED’s which are inter connected such that the positive terminal (anode) of each LED in the same column are connected together and the negative terminal (cathode) of each LED in the same row are connected together. Note that this could be the other way around as well, with the positive terminals connected to the rows and the negative terminals connected to the columns.
- 4. The Dot Matrix LED Display
- 5. An LED dot matrix display ( “dot” refers to the circular lenses in front of the LEDs) can also come with multiple LEDs of varying colors behind each dot in the matrix. For example, the matrix used in this lab has a Red, and Green behind each dot in the 8 x 8 grid. 8255 Port Address: Port Name Port Address Port A 18H Port B 1AH Port C 1CH Control Register 1EH The Dot Matrix LED Display
- 6. The Dot Matrix LED Display Connection
- 7. Control Word D7 D6 D5 D4 D3 D2 D1 DO I/0 Function Port A In Mode 0 Port A Output Port Cu Output Port B In Mode 0 Port B Output Port CL Output 1 0 0 0 0 0 0 0 = 80H The Dot Matrix LED Display
- 8. The Dot Matrix LED Pin Diagram
- 9. The Dot Matrix LED Display Experimental Setup
- 10. Matrix- Scroll bottom to top The Dot Matrix LED Display
- 11. The Dot Matrix LED Display
- 12. Matrix- Scroll left to right The Dot Matrix LED Display
- 13. Matrix- Display “A” The Dot Matrix LED Display
- 14. Matrix- Scroll “A” left to right The Dot Matrix LED Display
- 15. Matrix- Scroll “A” bottom to top The Dot Matrix LED Display