SED1330F Datasheet, PDF (85/148 Pages) List of Unclassifed Manufacturers – LCD Controller ICs

5.3 – 5.3.3
5.3 Cursor Control
5.3.1 Cursor Register Function
The SED1330F/1335F/1336F cursor address regis-
ter functions as both the displayed cursor position
address register and the display memory access
address register. When accessing display memory
outside the actual screen memory, the address regis-
ter must be saved before accessing the memory and
restored after memory access is complete.
Cursor register
Cursor display
address register
Address pointer
Figure 54. Cursor addressing
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 millisec-
onds.
5.0 Display Control Functions
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.
Although the cursor is normally displayed for charac-
ter data, the SED1330F/1335F/1336F may also dis-
play 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 address.
D=1
FC1 = 0
FC0 = 1
Cursor ON
FP1 = 0
FP0 = 0
Block screen 1 (character
screen) OFF
5.3.2 Cursor Movement
On each memory access, the cursor address register
changes by the amount previously specified with
CSRDIR, automatically moving the cursor to the de-
sired location.
FP3 = 0
FP2 = 1
Block screen 2 (graphics
screen) ON
Figure 55. Cursor display layers
5.3.3 Cursor Display Layers
Although the SED1330F/1335F/1336F 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
Consider the example of displaying Chinese charac-
ters 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 microproces-
sor must set the cursor address register when moving
the cursor over the graphical characters.
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