ch7008a Chrontel, ch7008a Datasheet - Page 28

• Manufacturer Part Number: ch7008a
• Description: Digital Pc To Tv Encoder
• Manufacturer: Chrontel

CHRONTEL
Register Descriptions (continued)
Position Overflow Register
This position overflow register contains the MSB values for the SAV, HP and VP values, as follows:
Black Level Register
This register sets the black level. The luminance data is added to this black level, which must be set between 90 and
208, with the default value being 127. Recommended values for NTSC and PAL-M are 127, 105 for PAL and 100
for NTSC-J.
Horizontal Position Register
The horizontal position register 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 position overflow register, bit HP8. Increasing this value moves the displayed
image position RIGHT; decreasing this value moves the displayed image position LEFT. Each increment moves the
image position by 4 input pixels.
28
Bit:
Symbol:
Type:
Default:
Bit:
Symbol:
Type:
Default:
Bit:
Symbol:
Type:
Default:
• VP8 (bit 0) is the MSB of the vertical position value (see explanation under “Vertical Position Register”).
• HP8 (bit 1) is the MSB of the horizontal position value (see explanation under “Horizontal Position
• SAV8 (bit 2) is the MSB of the start of active video value (see explanation under “Start Active Video
Register”).
Register”).
7
7
BL7
R/W
0
7
HP7
R/W
0
6
6
BL6
R/W
1
6
HP6
R/W
0
5
5
BL5
R/W
1
5
HP5
R/W
0
4
4
BL4
R/W
1
4
HP4
R/W
0
3
3
BL3
R/W
1
3
HP3
R/W
0
2
SAV8
R/W
0
2
BL2
R/W
1
2
HP2
R/W
0
201-0000-027 Rev 2.8, 6/24/2004
Address: 08H
Bits: 3
Address: 09H
Bits: 8
Address: 0AH
Bits: 8
Symbol: PO
Symbol: BLR
Symbol: HPR
1
HP8
R/W
0
1
BL1
R/W
1
1
HP1
R/W
0
CH7008A
0
VP8
R/W
0
0
BL0
R/W
1
0
HP0
R/W
0