SED1330F Datasheet, PDF (135/148 Pages) List of Unclassifed Manufacturers – LCD Controller ICs

9.3.2 – 9.4
• Graphics data table
• Contains graphics bitmaps
• Word length is 8 bits
• Table mapping can be changed
• CG RAM table
• Character generator memory can be
modified by the external microprocessor
• Character sizes up to 8 × 16 pixels (16
bytes per character)
• Maximum of 64 characters
• Table mapping can be changed
• CG ROM table
• Used when the internal character genera-
tor is not adequate
• Can be used in conjunction with the inter-
nal character generator and external char-
acter generator RAM
• Character sizes up to 8 × 16-pixels (16
bytes per character)
• Maximum of 256 characters
• Fixed mapping at F000H to FFFFH
9.0 Application Notes
9.4 Smooth Horizontal Scrolling
Figure 87 illustrates smooth display scrolling to the
left. When scrolling left, the screen is effectively
moving to the right, over the larger virtual screen.
Instead of changing the display start address SAD
and shifting the display by eight pixels, smooth scroll-
ing is achieved by repeatedly changing the pixel-shift
parameter of the HDOT SCR command. When the
display has been scrolled seven pixels, the HDOT
SCR pixel-shift parameter is reset to zero and SAD
incremented by one. Repeating this operation at a
suitable rate gives the appearance of smooth scroll-
ing.
To scroll the display to the right, the reverse proce-
dure is followed.
When the edge of the virtual screen is reached, the
microprocessor must take appropriate steps so that
the display is not corrupted. The scroll must be stopped
or the display modified.
Note that the HDOT SCR command cannot be used
to scroll individual layers.
268-0.4 _{S-MOS Systems, Inc. • 2460 North First Street • San Jose, CA 95131 • Tel: [phone] • Fax: [phone]}