Hi Alexey


The KSoo66 is pretty much a clone of the HD44780 , so timings etc will be pretty similar.
But you are right in thinking that you should treat them as two separate displays..
Although they share most connections(internally sync'ed),they do have two enable pins.And the addresses of line 1 and 2 are repeated at 3 and 4.
You do have to initialise each ks0066 separately.
Also remember that instrucion take anywhere from 40us to 1.7ms , so your software should check the busy flag.