z86229 ZiLOG Semiconductor, z86229 Datasheet - Page 43

• Manufacturer Part Number: z86229
• Description: Z86229 Ntsc Line 21 Ccd Decoder
• Manufacturer: ZiLOG Semiconductor

ZiLOG
The next group of commands use Graphic Char patterns to
make the two row word HELLO. The data byte of the WRITE
CHAR command is the address location for the graphic cell
required as illustrated in Figure 5.
Manual Row Mapping and Control
For most OSD displays, the POPSET, POP ROW SEL,
FLIP, TEXTSET, and RETURN commands should be used
to control row positioning.
TEXTSET mode provides automatic row allocation from
the top to bottom of a screen with all rows continuously vis-
ible. Additionally, TEXTSET screens have a definable ver-
tical window size and position, allowing support of auto-
matic text scrolling at the bottom of the window.
POPSET screens are created in off-screen memory while
the previous screen is displaying. Up to 8 rows of characters
can be defined. These rows can be mapped to any of 15 dis-
play rows using the POP ROW SEL command. Double-
high rows may also be defined with POP ROW SEL. The
FLIP command is then used to “pop-on” up to 8 rows of
characters replacing the previous screen. The off-screen
rows may be mapped to the same row numbers as the on-
screen rows.
In some applications, it may be necessary to access the dis-
play hardware at a lower level to achieve special screen ef-
fects. Examples of these special situations include the fol-
lowing:
1. More than 8 on-screen rows required in a “pop-on”
style screen.