ch7009a ETC-unknow, ch7009a Datasheet - Page 11

• Manufacturer Part Number: ch7009a
• Description: Chrontel Ch7009 Dvi / Tv Output Device
• Manufacturer: ETC-unknow

CHRONTEL
Input Clock and Data Formats
The 12 data inputs support 5 different multiplexed data formats, each of which can be used with a 1X clock
latching data on both clock edges, or a 2X clock latching data with a single edge. The data received by the
CH7009 can be used to drive the DVI output, the VGA to TV encoder, or directly drive the DAC’s. The
multiplexed input data formats are (IDF[2:0]):
IDF
0
1
2
3
4
For multiplexed input data formats, either both transitions of the XCLK/XCLK* clock pair, or each rising or
falling edge of the clock pair (depending upon MCP bit, rising refers to a rising edge on the XCLK signal, a
falling edge on the XCLK* signal) will latch data from the graphics chip. The multiplexed input data formats
are shown in the figures below. The Pixel Data bus represents a 12-bit or 8-bit multiplexed data stream, which
contains either RGB or YCrCb formatted data. The input data rate is 2X the pixel rate, and each pair of Pn
values (eg; P0a and P0b) will contain a complete pixel encoded as shown in the tables below. It is assumed
that the first clock cycle following the leading edge of the incoming horizontal sync signal contains the first
word (Pxa) of a pixel, if an active pixel was present immediately following the horizontal sync. This does not
mean that active data should immediately follow the horizontal sync, however. When the input is a YCrCb
data stream the color-difference data will be transmitted at half the data rate of the luminance data, with the
sequence being set as Cb, Y, Cr, Y, where Cb0,Y0,Cr0 refers to co-sited luminance and color-difference
samples and the following Y1 byte refers to the next luminance sample, per CCIR-656 standards (the clock
frequency is dependent upon the current mode, and is not 27MHz as specified in CCIR-656). All non-active
pixels should be 0 in RGB formats, and 16 for Y and 128 for CrCb in YCrCb formats.
201-0000-035 Rev 1.1, 5/8/2000
Description
12-bit multiplexed RGB input (24-bit color), (multiplex scheme 1)
12-bit multiplexed RGB2 input (24-bit color), (multiplex scheme 2)
8-bit multiplexed RGB input (16-bit color, 565)
8-bit multiplexed RGB input (15-bit color, 555)
8-bit multiplexed YCrCb input (24-bit color), (Y, Cr and Cb are multipl exed)
CH7009A
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