ADV7189B View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
'ADV7189B' PDF : 104 Pages View PDF
Table 33. AGC Modes
Input Video Type
Any
CVBS
Luma Gain
Manual gain luma.
Dependent on horizontal sync depth.
Peak White.
Y/C
Dependent on horizontal sync depth.
Peak White.
YPrPb
Dependent on horizontal sync depth.
Luma Gain
LAGC[2:0] Luma Automatic Gain Control, Address
0x2C[7:0]
The luma automatic gain control mode bits select the mode of
operation for the gain control in the luma path. There are ADI
internal parameters to customize the peak white gain control.
Contact ADI sakes for more information.
Table 34. LAGC Function
LAGC[2:0]
Description
000
Manual fixed gain (use LMG[11:0])
001
AGC (blank level to sync tip); peak white
algorithm off
010 (default)
AGC (blank level to sync tip); peak white
algorithm on
011
Reserved
100
Reserved
101
Reserved
110
Reserved
111
Freeze gain
LAGT[1:0] Luma Automatic Gain Timing, Address
0x2F[7:6]
The luma automatic gain timing register allows the user to
influence the tracking speed of the luminance automatic gain
control. Note this register only has an effect if the LAGC[2:0]
register is set to 001, 010, 011, or 100 (automatic gain control
modes).
If peak white AGC is enabled and active (see the
189HSTATUS_1[7:0] Address 0x10[7:0] section), the actual gain
update speed is dictated by the peak white AGC loop and, as a
result, the LAGT settings have no effect. As soon as the part
leaves peak white AGC, LAGT becomes relevant again.
The update speed for the peak white algorithm can be
customized by the use of internal parameters. Contact ADI
for more information.
ADV7189B
Chroma Gain
Manual gain chroma.
Dependent on color burst amplitude.
Taken from luma path.
Dependent on color burst amplitude.
Taken from luma path.
Dependent on color burst amplitude.
Taken from luma path.
Dependent on color burst amplitude.
Taken from luma path.
Taken from luma path.
Table 35. LAGT Function
LAGT[1:0]
Description
00
Slow (TC = 2 sec)
01
Medium (TC = 1 sec)
10
Fast (TC = 0.2 sec)
11 (default)
Adaptive
LG[11:0] Luma Gain, Address 0x2F[3:0]; Address
0x30[7:0]; LMG[11:0] Luma Manual Gain, Address
0x2F[3:0]; Address 0x30[7:0]
Luma Gain[11:0] is a dual-function register. If written to, a
desired manual luma gain can be programmed. This gain
becomes active if the LAGC[2:0] mode is switched to manual
fixed gain. Equation 1 shows how to calculate a desired gain. If
read back, this register returns the current gain value.
Depending on the setting in the LAGC[2:0] bits, this is one of
the following values:
• Luma manual gain value (LAGC[2:0] set to luma manual
gain mode)
• Luma automatic gain value (LAGC[2:0] set to any of the
automatic modes)
Table 36. LG/LMG Function
LG[11:0]/LMG[11:0] Read/Write
LMG[11:0] = X
Write
LG[11:0]
Read
Description
Manual gain for
luma path
Actually used gain
Luma _Gain = (0 < LG ≤ 4095) = 0...2
(1)
2048
Rev. B | Page 31 of 104
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