Datasheet

ADV7188
Rev. A | Page 89 of 112
Bit
1
Address Register Bit Description 7 6 5 43210Comments Notes
0 0 0 Not a valid setting
0 0 1 Chroma + two pixels (early)
0 1 0 Chroma + one pixel (early)
0 1 1 No delay
1 0 0 Chroma − one pixel (delayed)
1 0 1 Chroma − two pixels (delayed)
1 1 0 Chroma −three pixels (delayed)
CTA [2:0]. Chroma timing adjust. These bits
allow a specified timing difference between
the luma and chroma samples.
1 1 1 Not a valid setting
CVBS mode CTA [2:0] = 011b
S-video mode CTA [2:0] = 101b
YPrPb mode CTA [2:0] = 110b
0 Use values in LTA [1:0] and CTA [2:0]
for delaying luma and chroma
AUTO_PDC_EN. This bit automatically
programs the LTA/CTA values to align luma
and chroma at the output for all modes of
operation.
1 LTA and CTA values determined
automatically
0 No swapping
SWPC. This bit allows the Cr and Cb samples
to be swapped.
1 Swap the Cr and Cb output samples
0Update once per video line PW_UPD. Peak white update. This bit
determines the rate of gain change.
1 Update once per field
Peak white must be enabled (see
LAGC [2:0])
Reserved. 1 0 0 0 0 Set to default
0 Color kill disabled CKE. Color-kill enable. This bit allows the
color-kill function to be switched on and off.
1 Color kill enabled
For SECAM color kill, threshold is set at
8% (see CKILLTHR [2:0])
0x2B Miscellaneous
Gain Control
Reserved. 1 Set to default
0 0 Manual fixed gain Use CMG [11:0]
0 1 Use luma gain for chroma
1 0 Automatic gain Based on color burst
CAGC [1:0]. Chroma automatic gain control.
These bits select the basic mode of operation
for the AGC in the chroma path.
1 1 Freeze chroma gain
Reserved. 1 1 Set to 1
000 Manual fixed gain Use LMG [11:0]
0 0 1 Reserved Blank level to sync tip
0 1 0 AGC peak white algorithm enabled Blank level to sync tip
011 Reserved
1 0 0 AGC peak white algorithm disabled Blank level to sync tip
101 Reserved
110 Reserved
LAGC [2:0]. Luma automatic gain control.
These bits select the mode of operation for
the gain control in the luma path.
1 1 1 Freeze gain
0x2C AGC Mode Control
Reserved. 1 Set to 1
CG [11:8]/CMG [11:8]. Chroma manual gain.
These bits can be used to program a desired
manual chroma gain. Reading back from these
bits in AGC mode gives the current gain.
0 1 0 0 CAGC [1:0] must be set to 00 (manual
fixed gain) to use CMG [11:0].
Reserved. 1 1 Set to 1
00 Slow (TC = 2 sec)
01 Medium (TC = 1 sec)
10 Fast (TC = 0.2 sec)
0x2D Chroma Gain
Control 1
CAGT [1:0]. Chroma automatic gain timing.
These bits allow adjustment of the chroma
AGC tracking speed.
1 1 Adaptive
Has an effect only if CAGC [1:0] is set
to 10 (automatic gain).
0x2E Chroma Gain
Control 2
CG [7:0]/CMG [7:0]. Lower eight bits of chroma
manual gain. See CG [11:8]/CMG [11:8] for
description.
0 0 0 0 0 0 0 0 CMG [11:0] = 750d, gain is 1 in
NTSC; CMG [11:0] = 741d, gain
is 1 in PAL
Minimum value is 0d (G = −60 dB;
maximum value is 3750d (G = +5 dB).
LG [11:8]/LMG [11:8]. Luma manual gain.
These bits can be used to program a desired
manual chroma gain or to read back the actual
gain value used.
x x x x LAGC [2:0] settings decide in
which mode LMG [11:0] operates
Reserved. 1 1 Set to 1
00 Slow (TC = 2 sec)
01 Medium (TC = 1 sec)
10 Fast (TC = 0.2 sec)
0x2F Luma Gain Control 1
LAGT [1:0]. Luma automatic gain timing.
These bits allow adjustment of the luma AGC
tracking speed.
1 1 Adaptive
Only has an effect if LAGC [2:0] is set to
010 or 100 (autogain).
0x30 Luma Gain Control 2 LG [7:0]/LMG [7:0]. Luma manual gain. These
bits can be used to program a desired manual
chroma gain or to read back the actual gain
value used.
x x x x x x x x LMG [11:0] = 1128d, gain is 1 in
NTSC; LMG [11:0] = 1222d, gain
is 1 in PAL
Minimum value of NTSC is 1024
(G = 0.90) and of PAL is 1024 (G = 0.84);
Maximum value of NTSC is 4095
(G = 3.63) and of PAL is 4095 (G = 3.35).