S1D13700 Epson Electronics America, Inc., S1D13700 Datasheet - Page 52

• Manufacturer Part Number: S1D13700
• Description: LCD Controller ICs
• Manufacturer: Epson Electronics America, Inc.

DISPLAY CONTROL FUNCTIONS
9.3. Cursor Control
9.3.1. Cursor register function
The S1D13305 series cursor address register functions as
both the displayed cursor position address register and
the display memory access address register. When ac-
cessing display memory outside the actual screen memory,
the address register must be saved before accessing the
memory and restored after memory access is complete.
Note that the cursor may disappear from the display if the
cursor address remains outside the displayed screen
memory for more than a few hundred milliseconds.
9.3.2. Cursor movement
On each memory access, the cursor address register
changes by the amount previously specified with CSRDIR,
automatically moving the cursor to the desired location.
9.3.3. Cursor display layers
Although the S1D13305 series can display up to three
layers, the cursor is displayed in only one of these layers:
Two-layer configuration: First layer (L1)
Three-layer configuration: Third layer (L3)
The cursor will not be displayed if it is moved outside the
memory for its layer. Layers may be swapped or the
cursor layer moved within the display memory if it is
necessary to display the cursor on a layer other than the
present cursor layer.
46
Cursor register
Figure 34. Cursor addressing
Cursor display
address register
Address pointer
EPSON
Although the cursor is normally displayed for character
data, the S1D13305 series may also display a dummy
cursor for graphical characters. This is only possible if the
graphics screen is displayed, the text screen is turned off
and the microprocessor generates the cursor control ad-
dress.
Consider the example of displaying Chinese characters
on a graphics screen. To write the display data, the cursor
address is set to the second screen block, but the cursor is
not displayed. To display the cursor, the cursor address is
set to an address within the blank text screen block.
Since the automatic cursor increment is in address units,
not character units, the controlling microprocessor must
set the cursor address register when moving the cursor
over the graphical characters.
D = 1
FC1 = 0
FC0 = 1
FP1 = 0
FP0 = 0
FP3 = 0
FP2 = 1
Figure 35. Cursor display layers
Block screen 1 (character
screen) OFF
Block screen 2 (graphics
screen) ON
Cursor ON
S1D13305 Series
Technical Manual