ST7529 LASET and RAMWR commands

Hello,

I have a question concerning the commands of the ST7529 display driver.  I want to be able to write to a specific area of the display and am not sure how to use the LASET and RAMWR commands.

The datasheet for ST7529 states that when using LASET command the selected start and end lines of the display data RAM must be a pair (page 41). What does this actually mean? When are they a pair and when they are not? Can someone give me an example?

How about the RAMWR command, is the display updated immediately when I start writing to the RAM or only when the whole data set has been sent? I'm using the serial interface of the display and the controller that is connected to the display has to do some other tasks regularly so the updating of the screen must be paused during that. Can I write RAMWR command + start of the data, then have a pause, then continue sending the data, have a pause, continue, and then update the screen in the end when the whole data set is sent? Or does the display start to change immediately when the first new bytes are sent in?

 -Akseli