SAA5531 Philips Semiconductors, SAA5531 Datasheet - Page 80

• Manufacturer Part Number: SAA5531
• Description: Enhanced TV microcontrollers with On-Screen Display OSD
• Manufacturer: Philips Semiconductors

Philips Semiconductors
19.16 RGB brightness control
A brightness control is provided to allow the RGB upper
output voltage level to be modified. The nominal value is
1 V into a 150
0.7 and 1.2 V.
The brightness is set in RGB Brightness Register.
Table 31 RGB brightness
19.17 Contrast reduction
CC: This feature is not available in CC mode.
TXT: The COR bits in SFRs TXT5 and TXT6 control when
the COR output of the device is activated (i.e. pulled
LOW). This output is intended to act on the TVs display
circuits to reduce contrast of the video when it is active.
The result of contrast reduction is to improve the
readability of the text in a mixed teletext and video display.
The bits in the TXT5 and TXT6 SFRs allow the display to
be set up so that, for example, the areas inside teletext
boxes will be contrast reduced when a subtitle is being
displayed but that the rest of the screen will be displayed
as normal video.
2000 Feb 23
Enhanced TV microcontrollers with
On-Screen Display (OSD)
BRI3 TO BRI0
0000
1111
...
resistor, but can be varied between
RGB BRIGHTNESS
lowest value
...
highest value
80
20 MEMORY MAPPED REGISTERS (MMR)
The memory mapped registers are used to control the
display. The registers are mapped into the microcontroller
MOVX address space, starting at address 87F0H and
extending to 87FFH.
Table 32 MMR address summary
REGISTER
NUMBER
10
11
12
13
14
15
0
1
2
3
4
5
6
7
8
9
ADDRESS
MEMORY
87FCH
87FDH
87FBH
87FEH
87FFH
87F0H
87F1H
87F2H
87F3H
87F4H
87F5H
87F6H
87F7H
87F8H
87F9H
87FAH
Preliminary specification
Display Control
Text Position Vertical
Text Area Start
Fringing Control
Text Area End
Scroll Area
Scroll Range
RGB Brightness
Status
Reserved
Reserved
Reserved
HSYNC Delay
VSYNC Delay
Top Scroll Line
Configuration
FUNCTION
SAA55xx