AD9985ABSTZ-110 Analog Devices Inc, AD9985ABSTZ-110 Datasheet - Page 23

• Manufacturer Part Number: AD9985ABSTZ-110
• Description: IC,Data Acquisition Signal Conditioner,3-CHANNEL,8-BIT,CMOS,QFP,80PIN,PLASTIC
• Manufacturer: Analog Devices Inc

Specifications of AD9985ABSTZ-110

• Applications: Video
• Interface: Serial Port
• Voltage - Supply: 2.2 V ~ 3.45 V
• Package / Case: 80-LQFP
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

10
Table 28. Red Clamp Select Settings
Clamp
0
1
10
Table 29. Green Clamp Select Settings
Clamp
0
1
10
Table 30. Blue Clamp Select Settings
Clamp
0
1
11
12
2
This bit determines whether the Red channel is
clamped to ground or to midscale. For RGB video, all
three channels are referenced to ground. For YCbCr
(or YUV), the Y channel is referenced to ground, but
the CbCr channels are referenced to midscale.
Clamping to midscale actually clamps to Pin 37.
The default setting for this register is 0.
1
This bit determines whether the Green channel is
clamped to ground or to midscale.
The default setting for this register is 0.
0
This bit determines whether the Blue channel is
clamped to ground or to midscale.
The default for this register is 0.
7–0
This register is used to set the responsiveness of the
sync separator. It sets how many internal 5 MHz clock
periods the sync separator must count to before
toggling high or low. It works like a low-pass filter to
ignore Hsync pulses in order to extract the Vsync
signal. This register should be set to some number
greater than the maximum Hsync pulsewidth. Note
that the sync separator threshold uses an internal
dedicated clock with a frequency of approximately
5 MHz.
The default for this register is 32.
7–0
This register allows the coast signal to be applied prior
to the Vsync signal. This is necessary in cases where
pre-equalization pulses are present. The step size for
this control is one Hsync period.
The default is 0.
Red Clamp Select
Green Clamp Select
Blue Clamp Select
Pre-Coast
Function
Clamp to Ground
Clamp to Midscale (Pin 37)
Function
Clamp to Ground
Clamp to Midscale (Pin 37)
Function
Clamp to Ground
Clamp to Midscale (Pin 37)
Sync Separator Threshold
Rev. 0 | Page 23 of 32
13
14
Table 31. Hsync Detection Results
Detect
0
1
14
Table 32. Active Hsync Results
Bit 7
(Hsync
Detect)
0
0
1
1
X
14
7–0
This register allows the coast signal to be applied
following the Vsync signal. This is necessary in cases
where post-equalization pulses are present. The step
size for this control is one Hsync period.
The default is 0.
7
This bit is used to indicate when activity is detected on
the Hsync input pin (Pin 30). If Hsync is held high or
low, activity will not be detected.
The Sync Processing Block Diagram (Figure 14) shows
where this function is implemented.
6
This bit indicates which Hsync input source is being
used by the PLL (Hsync input or Sync-on-Green).
Bits 7 and 1 in this register determine which source is
used. If both Hsync and SOG are detected, the user
can determine which has priority via Bit 3 in
Register 0EH. The user can override this function via
Bit 4 in Register 0EH. If the override bit is set to
Logic 1, this bit will be forced to whatever the state of
Bit 3 in Register 0EH is set to.
AHS = 0 means use the Hsync pin input for Hsync.
AHS = 1 means use the SOG pin input for Hsync.
The override bit is in Register 0EH, Bit 4.
5
This bit reports the status of the Hsync input polarity
detection circuit. It can be used to determine the
polarity of the Hsync input. The detection circuit’s
location is shown in the Sync Processing Block
Diagram (Figure 14).
Bit 1
(SOG
Detect)
0
1
0
1
X
Post-Coast
Hsync Detect
AHS – Active Hsync
Detected Hsync Input Polarity Status
Function
No Activity Detected
Activity Detected
Bit 4,
Reg 0EH
(Override)
0
0
0
0
1
AHS
Bit 3 in 0EH
1
0
Bit 3 in 0EH
Bit 3 in 0EH
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