ch7009b Chrontel, ch7009b Datasheet - Page 28

• Manufacturer Part Number: ch7009b
• Description: Ch7009 Dvi / Tv Output Device
• Manufacturer: Chrontel

CHRONTEL
Text Enhancement Register
Bits 2-0 of register TE control the text enhancement circuitry within the CH7009. A value of ‘000’ minimizes the
enhancement feature, while a value of ‘111’ maximizes the enhancement.
Bits 5-3 of register TE contain the MSB values for the start of active video, horizontal position and vertical position
controls. They are described in detail in the SAV, HP and VP register descriptions.
Start of Active Video Register
Register SAV controls the delay, in pixel increments, from leading edge of horizontal sync to start of active video. The
entire bit field SAV[8:0] is comprised of this register SAV[7:0], plus the MSB value contained in the Text Enhancement
register, bit SAV8. This is decoded as a whole number of pixels, which can be set anywhere between 0 and 511 pixels.
Therefore, in any 2X clock mode the number of 2X clocks from the leading edge of sync to the first active data must be a
multiple of two clocks.
Horizontal Position Register
Register HP is used to shift the displayed TV image in a horizontal direction ( left or right) to achieve a horizontally
centered image on screen. The entire bit field, HP[8:0], is comprised of this register HP[7:0] plus the MSB value
contained in the Text Enhancement register, bit HP8. Increasing values move the displayed image position right, and
decreasing values move the image position left.
28
DEFAULT
DEFAULT
DEFAULT
SYMBOL
SYMBOL
SYMBOL
TYPE
TYPE
TYPE
BIT
BIT
BIT
SAV7
R/W
R/W
HP7
7
7
0
7
0
SenseSEL
SAV6
R/W
R/W
HP6
6
1
6
6
1
SAV5
SAV8
R/W
R/W
R/W
HP5
5
0
5
0
5
0
SAV4
R/W
R/W
R/W
HP8
HP4
4
1
4
0
4
1
SAV3
R/W
R/W
R/W
VP8
HP3
3
0
3
0
3
0
201-0000-035 Rev 3.31, 11/4/2004
SAV2
R/W
R/W
R/W
HP2
TE2
Symbol:
Address:
Bits:
Symbol:
Address:
Bits:
Symbol:
Address:
Bits:
2
0
2
1
2
0
SAV1
R/W
R/W
R/W
HP1
TE1
CH7009B
1
0
1
0
1
0
6
SAV
8
HP
8
TE
03h
04h
05h
SAV0
R/W
R/W
R/W
TE0
HP0
0
0
0
1
0
0