Update Array for Graphics Display
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Feb-01
In a graphics display, pel (picture element) data is stored in a multiplane memory. To update this memory, data is read into an update array, modified and then rewritten. A building block for the update array is disclosed which is implemented in Level Sensitive Scan Design (LSSD) Logic in which the cell count is minimized. The array is arranged so that test pattern generation may be automated. A general graphics display update operation consists of reading data from the all-points-addresable (APA) multiplane memory into the update array, performing some operation on the data, and then writing data back to the APA memory. Here, the update array is 8 pels by 8 planes, as shown in Fig. 1. The array consists of two 8-by-8 registers, called source and destination. These drive and/or are driven by an 8-bit data bus.