ch7004c Chrontel, ch7004c Datasheet - Page 33

• Manufacturer Part Number: ch7004c
• Description: Digital Pc To Tv Encoder With Macrovisiontm
• Manufacturer: Chrontel

CHRONTEL
RGBBP (bit 5): Setting this bit enables the RGB pass-through mode. Setting this bit to a 1 causes the input RGB
signal to be directly output at the DACs (subject to a pipeline delay). If RGBBP=0, the bypass mode is disabled.
DACG (bit 6): This bit controls the gain of the D/A converters. When DACG=0, the nominal DAC current is 71
μ
which provides the correct levels for PAL and NTSC-J.
Clock Mode Register
The setting of the clock mode bits determines the clocking mechanism used in the CH7004. The clock modes are
shown in the table below. PCM controls the frequency of the pixel clock, and XCM identifies the frequency of the
XCLK input clock.
Note: For what was formerly defined as the master mode, the user must now externally connect the P-OUT clock to the
XCLK input pin. Although it is possible to set the XCM [1:0] and PCM[1:0] values independent of the input data format,
there are only certain combinations of inpu data format, XCM and PCM, that will result in valid data being demultiplexed
at the input of the device. Refer to the “Input Data Format Register” for these combinations.
Note:
and 28 must use a 1X XCLK input data format.
201-0000-024 Rev. 2.4, 6/24/2004
Table 21. Input Data Format
A, which provides the correct levels for NTSC and PAL-M. When DACG=1, the nominal DAC current is 76
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001-1111
Bit:
Symbol:
Type:
Default:
IDF[3:0]
Display modes 25 and 26 must use a 2X multiplexed input data format and a 2X XCLK. Display modes 27
7
CFRB
R/W
0
16-bit non-multiplexed RGB (16-bit color, 565) input
16-bit non-multiplexed YCrCb (24-bit color) input (Y non-multiplexed, CrCb multiplexed
16-bit multiplexed RGB (24-bit color) input
15-bit non-multiplexed RGB (15-bit color, 555) input
12-bit multiplexed RGB (24-bit color) input (“C” multiplex scheme)
12-bit multiplexed RGB2 (24-bit color) input (“I” multiplex scheme)
8-bit multiplexed RGB (24-bit color, 888) input
8-bit multiplexed RGB (16-bit color, 565) input
8-bit multiplexed RGB (15-bit color, 555) input
8-bit multiplexed YCrCb (24-bit color) input (Y, Cr and Cb are multiplexed)
6
M/S*
R/W
0
5
Reserved
R/W
0
MCP
4
R/W
1
Description
3
XCM1
R/W
0
2
XCM0
R/W
0
Symbol: CM
Address: 06H
Bits: 8
1
PCM1
R/W
0
CH7004C
0
PCM0
R/W
0
μ
A,
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