Scan Line Scrolling Partitioned Display
Original Publication Date: 1988-Mar-01
Included in the Prior Art Database: 2005-Feb-15
Logic for a CRT display system is disclosed to allow smooth scrolling within a partition or window. To avoid the display of fractional character rows either at the top or bottom of the partition, which could not be interpreted, the logic blanks these characters out. The logic sets up the next full character row at the partition boundary. A partition is a window on a display screen; this is assumed to be on a character boundary for the purpose of clarity and simplicity. The contents of the partition can be scrolled up or down by a defined number of scan lines at a rate which is a multiple number of refresh cycles. Again, for simplicity, the scroll rate is set to one scan line change per screen refresh rate. Another simplification is achieved by defining the number of character scan lines as 16 (count 0-15).