Z86129 Datasheet, PDF (35/50 Pages) Zilog, Inc. – NTSC LINE 21 DECIDER

PRELIMINARY
Z86129/130/131
NTSC Line 21 Decoder
ON-SCREEN DISPLAY (Z86129 Only)
OSD Operation
These addresses are shared by the Extended Character
1 ^{The Z86129 has a fully programmable, general purpose set and the Graphics Character set. Any particular OSD}
OSD built in. The user can supply information for display screen can use one or the other of these sets of characters
through the serial port. In addition to all the normal and but not both.
extended features of the VBI data display modes, OSD
mode also has available added graphics characters, ^{The character set in force is controlled by the type of}
Double High and Double Wide characters and the ability to ^{display mode being invoked. When Drop Shadow is being}
position the display anywhere on the screen with an ^{used, by default, the Graphics Character set will be}
adjustable (vertical) box size. The double-high and double- ^{displayed in response to an address in the C0h-FFh range.}
wide characters are especially useful for creating OSD ^{However, if a BOX display is used, the Extended}
screens for display inside a Picture-in-Picture (PiP) ^{Character set is invoked. In either case the user can switch}
window. The OSD display mode can use either 13 or 15 ^{to the other set by means of the appropriate command,}
lines per row, with box or drop shadow. The default is 15 ^{GRAPHICS or EXTENDED.}
scan lines per row and drop shadow. Enhanced attributes
are always enabled.
The VIN/INTRO pin serves as the input for a Vertical Pulse
from the TV receiver when V Lock = VIN mode is enabled.
The 15 scan line per row display can only show 13 rows on ^{This permits an OSD display even when no video input is}
screen when in the NTSC mode. Rows 14 and 15 will be ^{present. If this mode is not required the default state V}
off screen and should not be addressed. In the PAL mode ^{Lock = VIDEO should be active and this pin will then carry}
all rows will be visible.
the INTRO output signal.
The 15 scan lines per row mode display can show the full
graphic characters and accented capital letters and
descenders without the potential overlap that would result
from the 13 scan line per row display. If the OSD display
mode is changed to a 13 scan line per row mode, the top
two scan lines of any graphics or accented capital letter will
be “ored” together with the bottom two scan lines from the
row above. In 13 line-drop shadow mode this will also
result in a side shadow effect. Graphics characters should
not be used in the 13 line-drop shadow mode.
OSD Character Set
There are 256 possible addresses in the OSD character
set. Figure 28 shows the address map in the range 00h-
BFh. This portion of the addressable space contains the
control bytes and regular character set. The address map
in the range C0h-FFh is shown in Figure 17.
OSD Commands
OSD commands are one and two byte commands. They
are used to control the loading of data for OSD display and
their presentation to the screen. Normally OSD display
mode uses 15 TV lines per display row to enhance the
OSD presentation.
The two byte commands enable direct access to any
location on the display screen. The user may construct
displays of his own choosing by using these commands.
Each command byte pair consists of an instruction byte
followed by a data byte. (See the Sample Z86129 OSD
Programs below.)
DS96TEL0200
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