AD9880/PCB Analog Devices Inc, AD9880/PCB Datasheet - Page 42

• Manufacturer Part Number: AD9880/PCB
• Description: BOARD EVALUATION PCB AD9880
• Manufacturer: Analog Devices Inc

Specifications of AD9880/PCB

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

AD9880
0x1B
Table 30. Blue Clamp
Select
0
1
0x1B
Table 31. Clamp During Coast
Select
0
1
0x1B
Table 32. Clamp Disable
Select
0
1
0x1B
Table 33. Bandwidth
Select
x0
x1
0x1B
Table 34. Auto Offset Hold
Select
0
1
0x1C
Result
Channel clamped to ground during clamping period
Channel clamped to midscale during clamping period
5
This bit selects whether the blue channel is clamped to
ground or midscale. Ground clamping is used for blue
in RGB applications and midscale clamping is used in
YPrPb (YUV) applications.
The power-up default is 0.
4
The power-up default is 0.
3
The power-up default is 0.
2-1
The power-up default is 1.
0
The power-up default is 0.
7
0 = manual offset
1 = auto offset using offset as target code. The power-
up default is 0.
Result
Clamping during Coast is disabled
Clamping during Coast is enabled
Result
Internal clamp enabled
Internal clamp disabled
Result
Low bandwidth
High bandwidth
Result
Normal auto offset operation
Hold current offset value
This bit permits clamping to be disabled during
Coast. The reason for this is video signals are
generally not at a known backporch or midscale
position during Coast.
Blue Clamp Select
Clamp During Coast
Clamp Disable
Programmable Bandwidth
Hold Auto Offset
Auto Offset Enable
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0x1C
0x1C
0x1C
0x1C
0x1C
0x1D
0x1E
0x1F
6-5
00 = every clamp
01 = every 16 clamps
10 = every 64 clamps
11 = every Vsync
The power-up default setting is 10.
4-3
00 = 100% of difference used to calculate new offset
01 = 50%
10 = 25%
11 = 12.5%
The power-up default is 01.
2
0 = normal operation
1 = if the code >15 codes off, the offset is jumped to
the predicted offset necessary to fix the >15 code mis-
match. The power-up default is 1.
1
The post filter reduces the update rate by 1/6 and
requires that all six updates recommend a change
before changing the offset. This prevents unwanted
offset changes.
0 = disable post filer
1 = enable post filter
The power-up default is 1.
0
The toggle filter looks for the offset to toggle back and
forth and holds it if triggered. This is to prevent
toggling in case of missing codes in the PGA.
1 = toggle filter on, 0 = toggle filter off.
The power-up default is 0.
7-0
Limits the amount the offset can change by in a single
update. The power-up default is 0x08.
7-0
This 8-bit register is programmed to set the number
of valid Hsyncs needed to lock the sync filter. This
ensures that a consistent, stable Hsync is present
before attempting to filter. The power-up default
setting is 32d.
7-0
This 8-bit register is programmed to set the number of
missing or invalid Hsyncs needed to unlock the sync
filter. This disables the filter operation when there is
no longer a stable Hsync signal. The power-up default
setting is 50d.
Slew Limit
Auto Offset Update Mode
Difference Shift Amount
Auto Jump Enable
Post Filter Enable
Toggle Filter Enable
Sync Filter Lock Threshold
Sync Filter Unlock Threshold