Datasheet

ADV7170/ADV7171
Rev. C | Page 42 of 64
APPENDIX 4—WIDE SCREEN SIGNALING
The ADV7170/ADV7171 support wide screen signaling (WSS) conforming to the standard. WSS data is transmitted on Line 23.
WSS data can only be transmitted when the ADV7170/ADV7171 are configured in PAL mode. The WSS data is 14 bits long; the function
of each of these bits is as shown below.
The WSS data is preceded by a run-in sequence and a start code (see Figure 58). The bits are output from the configuration registers in
the following order:
C/W20 = W0, C/W21 = W1, C/W22 = W2, C/W23 = W3, C/W24 = W4, C/W25 = W5, C/W26 = W6, C/W27 = W7, C/W10 = W8,
C/W11 = W9, C/W12 = W10, C/W13 = W11, C/W14 = W12, C/W15 = W13.
If Bit C/W07 is set to a Logic Level 1, it enables the WSS data to be transmitted on Line 23. The latter portion of Line 23 (42.5 μs from the
falling edge of
HSYNC
) is available for the insertion of video.
Function of CGMS Bits
Bit 0 to Bit 2 Aspect Ratio/Format/Position
Bit 3 is odd parity check of Bit 0 to Bit 2
B0 B1 B2 B3 Aspect Ratio Format Position
0 0 0 1 4:3 Full format Nonapplicable
1 0 0 0 14:9 Letterbox Center
0 1 0 0 14:9 Letterbox Top
1 1 0 1 16:9 Letterbox Center
0 0 1 0 16:9 Letterbox Top
1 0 1 1 >16:9 Letterbox Center
0 1 1 1 14:9 Full format Center
1 1 1 0 16:9 Nonapplicable Nonapplicable
B4
0 Camera Mode
1 Film Mode
B5
0 Standard Coding
1 Motion Adaptive Color Plus
B6
0 No Helper
1 Modulated Helper
B7 RESERVED
B9 B10
0 0 No open subtitles
1 0 Subtitles in active image area
0 1 Subtitles out of active image area
1 1 Reserved
B11
0 No surround sound information
1 Surround sound mode
B12 RESERVED
B13 RESERVED
11.0μs
W0 W1 W2 W3 W4 W5 W6 W7 W8 W9 W10 W11 W12 W13
500mV
RUN-IN
SEQUENCE
START
CODE
ACTIVE
VIDEO
38.4μs
42.5μs
00221-058
Figure 58. WSS Waveform Diagram