SAA5500PS Philips Semiconductors, SAA5500PS Datasheet - Page 62

• Manufacturer Part Number: SAA5500PS
• Description: Standard TV Microcontrollers with On-Screen Display(OSD)
• Manufacturer: Philips Semiconductors

Philips Semiconductors
19.12 Video/data switch adjustment
To take into account the delay between the RGB values
and the VDS signal due to external buffering, the VDS
signal can be moved in relation to the RGB signals.
The VDS signal can be set to be either a clock cycle before
or after the RGB signal, or coincident with the RGB signal.
This is done using VDEL<2:0> in the MMR Configuration.
19.13 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 15
0.7 and 1.2 V.
The brightness is set in the RGB Brightness Register.
Table 21 RGB brightness
19.14 Contrast reduction
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.
1999 Oct 27
BRI3 TO BRI0
Standard TV microcontrollers with
On-Screen Display (OSD)
0000
1111
...
resistor, but can be varied between
lowest value
...
highest value
RGB BRIGHTNESS
62
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 22 MMR address summary
REGISTER
NO.
12
13
15
1
2
3
4
7
8
ADDRESS
MEMORY
87FCH
87FDH
87F1H
87F2H
87F3H
87F4H
87F7H
87F8H
87FFH
Preliminary specification
Text Position Vertical
Text Area Start
Fringing Control
Text Area End
RGB Brightness
Status
HSYNC Delay
VSYNC Delay
Configuration
FUNCTION
SAA55xx