
ADV7188
Rev. A | Page 87 of 112
Bit1
Address
Register
Bit Description
7 6 5 4 3 2 1 0 Comments
Notes
FREE_RUN_ACT.
x
1 = free-run mode active
Blue screen output
STD_FLD_LEN.
x
1 = field length standard
Correct field length found
INTERLACED.
x
1 = interlaced video detected
Field sequence found
PAL_SW_LOCK.
x
1 = swinging burst detected
Reliable swinging burst sequence
Reserved.
0 0
0
Crystal used to derive
28.63636 MHz clock
XTAL_TTL_SEL.
1
External TTL level clock supplied
Analog Control
Internal (Write Only)
Reserved.
0 0 0 0 0
Reserved.
0 0 1 0 Set to default
0
Current sources switched off
CCLEN. Current clamp enable. This bit allows
the user to switch off the current sources in
the analog front end.
1
Current sources enabled
0x14
Analog Clamp
Control
Reserved.
0 0 0
Set to default
Reserved.
x
Set to default
0
Disable digital clamp freeze
DCFE. Digital clamp freeze enable.
1
Enable digital clamp freeze
0 0
Slow (TC = 1 sec)
0 1
Medium (TC = 0.5 sec)
1 0
Fast (TC = 0.1 sec)
DCT [1:0]. Digital clamp timing. These bits
determine the time constant of the digital
fine-clamp circuitry.
1 1
TC dependent on video
0x15
Digital Clamp
Control 1
Reserved.
0
Set to default
0 0 0 0 0 Automatically uses wide notch
filter for poor quality sources and
wideband filter with comb for
good quality input
0 0 0 0 1 Automatically uses narrow notch
filter for poor quality sources and
wideband filter with comb for
good quality input
Decoder selects optimum Y-shaping
filter depending on CVBS quality.
0 0 0 1 0 SVHS 1
0 0 0 1 1 SVHS 2
0 0 1 0 0 SVHS 3
0 0 1 0 1 SVHS 4
0 0 1 1 0 SVHS 5
0 0 1 1 1 SVHS 6
0 1 0 0 0 SVHS 7
0 1 0 0 1 SVHS 8
0 1 0 1 0 SVHS 9
0 1 0 1 1 SVHS 10
0 1 1 0 0 SVHS 11
0 1 1 0 1 SVHS 12
0 1 1 1 0 SVHS 13
0 1 1 1 1 SVHS 14
1 0 0 0 0 SVHS 15
1 0 0 0 1 SVHS 16
1 0 0 1 0 SVHS 17
0x17
Shaping Filter
Control
1 0 0 1 1 SVHS 18 (CCIR 601)
1 0 1 0 0 PAL NN 1
1 0 1 0 1 PAL NN 2
1 0 1 1 0 PAL NN 3
1 0 1 1 1 PAL WN 1
1 1 0 0 0 PAL WN 2
1 1 0 0 1 NTSC NN1
1 1 0 1 0 NTSC NN2
1 1 0 1 1 NTSC NN3
1 1 1 0 0 NTSC WN 1
1 1 1 0 1 NTSC WN 2
1 1 1 1 0 NTSC WN 3
YSFM [4:0]. Selects Y-shaping filter mode
when in CVBS only mode. These bits allow
the user to select a wide range of low-pass
and notch filters.
1 1 1 1 1 Reserved
If one of these modes is selected, the
decoder does not change filter modes.
A fixed filter response (the one selected)
is used regardless of video quality.