AD9883/PCB AD [Analog Devices], AD9883/PCB Datasheet - Page 19

• Manufacturer Part Number: AD9883/PCB
• Description: 110 MSPS Analog Interface for Flat Panel Displays
• Manufacturer: AD [Analog Devices]

14
14
14
Table XXVIII. Detected Hsync Input Polarity Status
Bit 7
(Hsync
Detect)
0
0
1
1
X
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 Detected Hsync Input Polarity Status
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.
Hsync Polarity Status
0
1
4 Vsync Detect
This bit is used to indicate when activity is detected on
the Vsync input pin, (Pin 31). If Vsync is held high or
low, activity will not be detected.
Detect
0
1
The Sync Processing Block Diagram shows where this
function is implemented.
3 AVS – Active Vsync
This bit indicates which Vsync source is being used; the
Vsync input or output from the sync separator. Bit 4 in
this register is what determines which is active. If both
Vsync and SOG are detected the user can determine
which has priority via Bit 0 in register 0EH. The user can
override this function via Bit 1 in register 0EH. If the
override bit is set to Logic 1, then this bit will be forced to
whatever the state of Bit 0 in register 0EH is set to.
Table XXIX. Vsync Detection Results
Table XXVII. Active Hsync Results
Bit 1
(SOG
Detect)
0
1
0
1
X
Function
No Activity Detected
Activity Detected
Bit 4, Reg
0EH
(Override)
0
0
0
0
1
Result
Hsync Polarity Is Negative
Hsync Polarity Is Positive
AHS
Bit 3 in 0EH
1
0
Bit 3 in 0EH
Bit 3 in 0EH
14
14
14
Table XXXIII. Detected Coast Input Polarity Status
Bit 5
(Vsync Detect)
0
1
X
AVS = 0 means Sync separator.
AVS = 1 means Vsync input.
The override bit is in register 0EH, Bit 1.
2
This bit reports the status of the Vsync output polarity
detection circuit. It can be used to determine the polarity
of the Vsync output. The detection circuit’s location is
shown in the Sync Processing Block Diagram.
Vsync Polarity Status
0
1
1
This bit is used to indicate when sync activity is detected
on the sync-on-green input pin, (Pin 49).
Detect
0
1
The sync processing block diagram shows where this
function is implemented.
0
This bit reports the status of the coast input polarity
detection circuit. It can be used to determine the polarity
of the coast input. The detection circuit’s location is shown
in the Sync Processing Block Diagram.
Hsync Polarity Status
0
1
Table XXXI. Detected Vsync Output Polarity Status
Table XXXII. Sync-on-Green Detection Results
Detected Vsync Output Polarity Status
Detected COAST Polarity Status
Sync-on-Green Detect
Table XXX. Active Vsync Results
Function
No Activity Detected
Activity Detected
Override
0
0
1
Result
Coast Polarity Is Negative
Coast Polarity Is Positive
Result
Vsync Polarity Is Active High
Vsync Polarity Is Active Low
AVS
0
1
Bit 0 in 0EH
AD9883