I am about to start a project using a Hitachi (actually Renesas) graphics LCD controller - HD66789R.
I've never done any graphics programming before and when reading the data sheet I noticed that the controller has graphics bit operations to "significantly lessen the graphics processing load on software".
The controller uses 18 bits per GRAM location (8*R, 8*G, 8*B) for262,144 colours
The graphics bit operations include:
- Write data mask function that selectively rewrites some of the bits of 18-bit write data.
- Conditional rewrite function that compares the write data sent from the microcomputer and the data in the compare register and writes the data only when a condition is satisfied.
Can somebody with experience of this kind of controller explain exactly how these bit operations are intended to be used to reduce software overhead ?