CH7303 ETC [List of Unclassifed Manufacturers], CH7303 Datasheet - Page 7

• Manufacturer Part Number: CH7303
• Description: Chrontel CH7303 HDTV / DVI Encoder
• Manufacturer: ETC [List of Unclassifed Manufacturers]

CHRONTEL
2.3.2
The graphics controller interface can operate at a variable voltage level controlled by the voltage on the VDDV pin. This
should be set to the maximum voltage of the interface (typically 3.3V or adjustable between 1.1 and 1.8V). The VREF
pin is the voltage reference for the data, date enable, clock and sync inputs and must be tied to VDDV/2. This is typically
done using a resistor divider.
2.3.3
Figure 3 below shows the timing diagram for input data and clocks. The first XCLK/XCLK* waveform represents the
input clock for single edge transfer (SDR) methods. The second XCLK/XCLK* waveform represents the input clock for
the dual edge transfer (DDR) method. The timing requirements are given in section Error! Reference source not
found..
2.3.4
The de-skew feature allows adjustment of the input setup and hold time. The input data D[14:0] can be latched slightly
before or after the latching edge of XCLK depending on the amount of the de-skew. Note that the XCLK is not changed,
only the time at which the data is latch relative to XCLK. .The de-skew is controlled using the XCMD[3:0] bits located
in CH7303 register. The delay t
t
where
2.3.5
The CH7303 supports 9 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 (rising or falling depending on the value of the MCP bit
– rising refers to a rising edge on the XCLK signal, a falling edge on the XCLK* signal). The input data formats are
(IDF[2:0]):
IDF
0
1
2
3
4
5
6
7
8
209-0000-031
t
CD
XCLK/
XCLK*
XCLK/
XCLK*
D[11:0]
H
V
CD
= - XCMD[3:0] * t
= (XCMD[3:0] – 8) * t
XCMD is a number between 0 and 15 represented as a binary code
t
STEP
Interface Voltage Levels
Input Clock and Data Timing Diagram
Data De-skew Feature
Input Data Formats
is the adjustment increment
Description
12-bit multiplexed RGB input (24-bit color), (multiplex scheme 1)
12-bit multiplexed RGB 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 multiplexed)
12-bit multiplexed RGB input (24-bit color), (multiplex scheme A3 - edge-pair)
15-bit multiplexed RGB input (30-bit color), (multiplex scheme B1 - half-half mode)
15-bit multiplexed RGB input (30-bit color), (multiplex scheme B2 - half-color mode)
15-bit multiplexed RGB input (30-bit color), (multiplex scheme B3 - edge pair mode)
Rev. 0.4,
STEP
STEP
for 0 ≤ XCMD[3:0] ≤ 7
8/26/2002
CD
for 8 ≤ XCMD[3:0] ≤ 15
between clock and data is given by the following formula:
Figure 3: Clock, Data and Interface Timing
CH7303
7