The Theory
So the basic theory is to forget what you knew about creating stuff on the screen with the basic VGA pixel setting methods and move onto a more 'segmented display' type of approach. This means you should try to think of the monitor output more like this picture:
The Maximum
If you count carefully you'll see there is a maximum of 1200 boxes that show up on the screen. Even though they are shown as all blank, each one of those boxes could potentially be a character or custom bitmap. Taking this approach to generate VGA output can lead to alot of innovative creations from games to useful programs.
Our Implementation
The character rom that we will build will be fairly small in terms of memory required (around 4k). This will give us enough rom space for all the characters in the alphabet and some special characters. As seen in the sample entity above, each rom character will have an address location inside the rom for when it needs to be called.
So the basic theory is to forget what you knew about creating stuff on the screen with the basic VGA pixel setting methods and move onto a more 'segmented display' type of approach. This means you should try to think of the monitor output more like this picture:
The Maximum
If you count carefully you'll see there is a maximum of 1200 boxes that show up on the screen. Even though they are shown as all blank, each one of those boxes could potentially be a character or custom bitmap. Taking this approach to generate VGA output can lead to alot of innovative creations from games to useful programs.
The character rom that we will build will be fairly small in terms of memory required (around 4k). This will give us enough rom space for all the characters in the alphabet and some special characters. As seen in the sample entity above, each rom character will have an address location inside the rom for when it needs to be called.