Z90251 ZILOG [Zilog, Inc.], Z90251 Datasheet - Page 30

• Manufacturer Part Number: Z90251
• Description: eZVision 200 Television Controllers with OSD
• Manufacturer: ZILOG [Zilog, Inc.]

5
On-Screen Display
5.1
The On-Screen Display (OSD) module generates and displays a 10 row by 24
columns of 512 characters at 14 x 18-dots resolution. The color of each character
can be specified independently.
The televison OSD controller uses H
internal circuitry to the video signal, then outputs RGB and Video Blank (VBLANK)
signals. The VBLANK signal is used to multiplex the OSD signal and video signal
onto the screen. The result is that the On-Screen Display is superimposed over
the TV picture.
The display results from the successful timing of several components:
•
•
•
•
•
•
OSD Position
OSD Positioning is controlled by programming the following registers:
•
•
•
OSD Control Register
Table 8
Bit
R/W
Reset
Note: R = Read W = Write X = Indeterminate
OSD Positioning
Second Color Feature
Mesh and Halftone Effect
OSD Fade
Inter-Row Spacing
Character Generation
OSD Control Register (Table 8)
Vertical Position Register (Table 9)
Horizontal Position Register (Table 10)
OSD Control Register 00h:Bank A (OSD_CNTL)
7
R/W
0
6
R/W
x
5
R/W
x
SYNC
4
32 KB Television Controller with OSD
R/W
and V
x
3
SYNC
R/W
x
signals to synchronize its
2
R/W
x
1
R/W
PS001301-0800
x
0
R/W
x
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