LM1238 National Semiconductor Corporation, LM1238 Datasheet - Page 21

• Manufacturer Part Number: LM1238
• Description: 110 Mhz I2c Compatible Rgb Preamplifier With Internal Simple Osd Generator And 4 Dacs
• Manufacturer: National Semiconductor Corporation

Control Register Definitions
Icon Alternate Period Control Register (I
Register Name (address): ALT (0x0804h)
Bits 3–0 Icon Alternate Period. These four bits set the period at which the icon will switch between images, in increments of eight
Bits 5–4 Alternate Sequence Override. These two bits enable the automatic alternating sequence of icons, or allow the icon to
Bits 7–6 Reserved.
Vertical Blank Duration Control Register (I
Register Name (address): VERTBLNK (0x0805h)
Bits 6–0 Vertical Blank Duration. These seven bits set the duration of the VBLANK signal in numbers of horizontal scans.
Bit 7
PRE-AMPLIFIER INTERFACE REGISTERS
Blue Channel Gain Control Register (I
Register Name (address): BGAINCTRL (0x0810h)
Bits 6–0 Blue Channel Gain Control. These seven bits determine the gain for the Blue Channel.
Bit 7
Green Channel Gain Control Register (I
Register Name (address): GGAINCTRL1 (0x0811h)
Bits 6–0 Green Channel Gain Control. These seven bits determine the gain for the Green Channel.
Bit 7
Red Channel Gain Control Register (I
Register Name (address): RGAINCTRL1 (0x0812h)
Bits 6–0 Red Channel Gain Control. These seven bits determine the gain for the Red Channel.
Bit 7
vertical fields.
be set to one of the three alternative screens.
Reserved.
Reserved.
Reserved.
Reserved.
RSV
RSV
RSV
RSV
RSV
7
7
7
7
7
Sequence Override
Register Value
RSV
VB6
GG
BG
RG
6
6
6
6
6
00
01
10
11
TABLE 8. Alternating Icon Sequence Override
2
2
C address 0x0812h)
C address 0x0810h)
2
2
ASO1
C address 0x0811h)
VB5
C address 0x0804h)
BG
GG
RG
2
5
5
5
5
5
C address 0x0805h)
(Continued)
ASO0
VB4
GG
RG
BG
4
4
4
4
4
Automatic Alternating Sequence
21
ALT3
Set for Icon Screen 0
Set for Icon Screen 1
Set for Icon Screen 2
VB3
GG
BG
RG
3
3
3
3
3
Effect
ALT2
VB2
BG
GG
RG
2
2
2
2
2
ALT1
VB1
GG
RG
BG
1
1
1
1
1
ALT0
VB0
GG
RG
BG
0
0
0
0
0
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