CH7006C-V ETC, CH7006C-V Datasheet - Page 35

• Manufacturer Part Number: CH7006C-V
• Description: Digital PC to TV Encoder Features
• Manufacturer: ETC

CHRONTEL
Register Descriptions (continued)
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 input 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: Display modes 25 and 26 must use a 2X multiplexed input data format and a 2X XCLK. Display modes 27
and 28 must use a 1X XCLK input data format.
The Clock Mode Register also contains the following bits:
Start Active Video Register
This register sets the delay in pixel increments from leading edge of horizontal sync, or the rising edge of data start,
to the start of active video. The entire bit field SAV[8:0] is comprised of this register SAV[7:0], plus the MSB value
contained in the position overflow register, bit SAV8. This is decoded as a whole number of pixels, which can be
set anywhere between 0 and 511 pixels. Therefore, in any 2X clock mode, the number of 2X clocks from the
leading edge of sync to the first active data must be a multiple of two clocks. In any 3X clock mode, the number of
3X clocks from the leading edge of sync to the first active data must be a multiple of three clocks. When using the
DS/BCO pin as a data start input, this register should be set to decimal value 11.
Table 21. Input Data Format Register
201-0000-026 Rev 2.1, 8/2/99
XCM[1:0]
00
00
00
01
01
01
1X
1X
1X
Bit:
Symbol:
Type:
Default:
• MCP (bit 4) determines which edge of the pixel clock output will be used to latch input data. Zero selects the
• M/S* (bit 6) determines whether the device operates in master or slave clock mode. In master mode (1), the
• CFRB (bit 7) sets whether the chroma subcarrier free-runs, or is locked to the video signal. One causes the
negative edge, one selects the positive edge.
14.31818MHz clock is used as a frequency reference to the PLL. In slave mode (0) the XCLK input is used as
a reference to the PLL, and is divided by the value specified by XCM[1:0]. The divide by N and M are forced
to one.
subcarrier to lock to the TV vertical rate, and should be used when the ACIV bit is set to zero. Zero causes the
subcarrier to free-run, and should be used when the ACIV bit is set to one.
7
SAV7
R/W
0
PCM[1:0]
00
01
1X
00
01
1X
00
01
1X
6
SAV6
R/W
0
XCLK
1X
1X
1X
2X
2X
2X
3X
3X
3X
5
SAV5
R/W
0
P-OUT
1X
2X
3X
1X
2X
3X
1X
2X
3X
4
SAV4
R/W
0
Input Data Modes Supported
0, 1, 2, 3, 4, 5, 7, 8, 9
0, 1, 2, 3, 4, 5, 7, 8, 9
0, 1, 2, 3, 4, 5, 7, 8, 9
2, 4, 5, 7, 8, 9
2, 4, 5, 7, 8, 9
2, 4, 5, 7, 8, 9
6
6
6
3
SAV3
R/W
0
2
SAV2
R/W
0
Symbol: SAV
Address: 07H
Bits: 8
1
SAV1
R/W
0
CH7006C
0
SAV0
R/W
0
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