The LED display is used to display data in a host of industrial, commercial and consumer
electronic products. It is especially used in products designed for situations of poor
lighting and a rugged environment.

PREREQUISITES

        Course-A1. Introduction to VHDL and VLSI design (I)


CONTENTS

1. Design of Video Ram (VRAM)- size, Text and Graphic pages.
   
2. Design of Character Graphic Rom (CGROM) and font table.
   
3. Design of VRAM text page (attribute and data bytes).
   
4. Power on logic.
   
5. Control register for display on/off, graphic/text mode, cursor on/off and cursor dimensions.
   
6. State counter and decoder for internal timing and control.
   
7. Blink frequency generator, for cursor blinking.
   
8. VRAM address generator.
   
9. Generation of signals for memory and bus control:-
          VRAM, CGROM chip select
          VRAM, CGROM read/write
          Output Enable for Controller data buffer
          IOCHRDY-Indicates VRAM,CGROM address bus is with controller (CPU must wait). 
   
10. Registers for data sent by VRAM.
    
11. CGROM address from VRAM data for text mode.
    
12. External address mux for VRAM,CGROM,CPU depending on kind of access.
    
13. External address registers.
    
14. Mux for data read from CGROM (text) and VRAM (graphic).
    
15. Modification of read data for text/graphic mode, cursor on/off, blinking and input to shift registers.
    
16. Parallel shift registers for LCD data.
    
17. Generation of LCD interface signals:-
              CL1 - End of Line
              CL2 - End of Character
              FLM - Start Of Frame
              DATA[] - LCD Data