adv7180 Analog Devices, Inc., adv7180 Datasheet - Page 60

• Manufacturer Part Number: adv7180
• Description: 10-bit, 4 X Oversampling Sdtv Video Decoder
• Manufacturer: Analog Devices, Inc.

ADV7180
CGMS and WSS
The CGMS and WSS data packets convey the same type of
information for different video standards. WSS is for PAL and
CGMS is for NTSC, so the CGMS and WSS readback registers
are shared. WSS is biphase coded; the VDP does a biphase
decoding to produce the 14 raw WSS bits in the CGMS/WSS
readback I
CGMS_WSS_CLEAR, CGMS/WSS Clear, Address 0x78 [2],
User Sub Map, Write Only, Self-Clearing
1—Reinitializes the CGMS/WSS readback registers.
Table 77. CGMS Readback Registers
Signal Name
CGMS_WSS_DATA_0[3:0]
CGMS_WSS_DATA_1[7:0]
CGMS_WSS_DATA_2[7:0]
1
The register is a readback register; default value does not apply.
2
C registers and to set the CGMS_WSS_AVL bit.
+100 IRE
+70 IRE
–40 IRE
0 IRE
11.0µs
11.2µs
SEQUENCE
1
RUN-IN
2.235µs ± 20ns
Register Location
VDP_CGMS_WSS_DATA_0[3:0]
VDP_CGMS_WSS_DATA_1[7:0]
VDP_CGMS_WSS_DATA_2[7:0]
REF
START
CODE
38.4µs
42.5µs
0
0
VDP_CGMS_WSS_DATA_2
Figure 44. CGMS Waveform
VDP_CGMS_WSS_DATA_2
Figure 43. WSS Waveform
1
1
Rev. B | Page 60 of 112
2
2
3
3
4
4
5
5
CGMS_WSS_AVL, CGMS/WSS Available, Address 0x78 [2],
User Sub Map, Read Only
0—CGMS/WSS was not detected.
1—CGMS/WSS was detected.
CGMS_WSS_DATA_0[3:0], Address 0x7D [3:0];
CGMS_WSS_DATA_1[7:0], Address 0x7E [7:0];
CGMS_WSS_DATA_2[7:0], Address 0x7F [7:0];
User Sub Map, Read Only
These bits hold the decoded CGMS or WSS data.
Refer to Figure 43 and Figure 44 for the I
bit mapping.
6
6
7
7
VDP_CGMS_WSS_
DATA_1[5:0]
0
0
49.1µs ± 0.5µs
1
VDP_CGMS_WSS_DATA_1
1
2
2
3
3
4
4
5
125
126
127
5
6
ACTIVE
Address (User Sub Map)
CRC SEQUENCE
VIDEO
7
VDP_CGMS_WSS_
DATA_0[3:0]
0
1
2
C to WSS and CGMS
2
3
0x7D
0x7E
0x7F