VGA_Controler

The project's structure is expanded below

    +--- topModule      
        |
        +--- pixelClk            
        |
        +--- kbdController    
        |   |
        |   +--- kbdHandler   
        |   |
        |   +--- ps2Decode    
        |
        +--- inputDecode  
        |    | 
        |    +--- colorHandler
        |    |    |
        |    |    +--- UpDownCounter3bit 
        |    |
        |    +--- flashHandler  
        |         |
        |         +--- flashClk 
        |             |
        |             +--- cnt64 
        |             |
        |             +--- cnt25 
        |
        +--- dispController
        |   |
        |   +--- vgaHandler
        |   |
        |   +--- charController
        |   |
        |   +--- offsetHandler
        |
        +--- romController 
            |
            +--- charRom             

Character ROM

  '00111000' /*   ###    */
  '01111000' /*  ####    */
  '11111000' /* #####    */
  '10111000' /* ## ##    */
  '00011000' /*    ##    */
  '00011000' /*    ##    */
  '00011000' /*    ##    */
  '00011000' /*    ##    */
  '00011000' /*    ##    */
  '00011000' /*    ##    */
  '00011000' /*    ##    */
  '00011000' /*    ##    */
  '00011000' /*    ##    */
  '00011000' /*    ##    */
  '11111111' /* ######## */
  '11111111' /* ######## */

All characters are stored in the charROM(16x8bit) which contains the pattern of pixels being on the screen whether a particular character needs to be displayed. The bits within the rom indicate which pixels of a 16x8 bit tile should be displayed. By default rom stores pattern for characters 1,2,3 and 4.

Functionality

In the initial state, after the synchronization with the VGA interface the screen remains black. In order to display (default position is the center of the screen) the prefered character on the screen user can press the respective key to the available characters stored in the rom module.

Position change

		- - - - - - - - - - - - - - - - - - - - - -
		|                                         |
		|                                         |
		|                  ---   ^                |
		|                 | # |  Y                |
		|                  ---   v                |
		|                 < X >                   |
		|                                         |
		- - - - - - - - - - - - - - - - - - - - - -

Using the arrow keys character moves on the screen in the corresponding direction by X or Y pixels defined by the character's dimensions (default 16x8). Moving offset (speed) can be adjusted and increased up to 4*X,Y using +,- keys. In the case where the character region reaches the limits of the visible screen, character region is being folded to the oposite side of the screen.

Colour change

The color of the active pixels (default white) of a character can be changed by pressing the keys r, g and b. Every press of such a key increases the caracter's respective color (3-bits) component. Furthermore, user has the option to change the color of the background (default black) by pressing the key 'i'. In this case using the above exactly procedure color of the background component can be changed. A press of the key 'i' switches changing color mode back to character's region and vise versa.

Flash

By pressing the key 'f' character starts to flash on the screen with frequency depending on the clock defined on the flashClk module.