VGA Interface
Where does the pixel value come from?
The image to be displayed is stored in memory
- “frame buffer”
- XS40 SRAM is 32Kx8
- max image size =
- 6 bits/pixel = 2 bits each of RGB (modest color)
Frame buffer model
- User fills memory with image
- User can change the image by just writing to memory
- Monitor reads memory whenever it needs a pixel
- Memory is shared, but user doesn’t need to know what monitor is doing
- modularization, information hiding
- VGA interface only needs to worry about reading the memory