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Table XXVII. Active Hsync Results

Bit 7

Bit 1

Bit 4, Reg

(Hsync

(SOG

0EH

Detect)

(Override)

AHS

Bit 3 in 0EH

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.

Table XXVIII. Detected Hsync Input Polarity Status

Hsync Polarity Status

Result

Hsync Polarity Is Negative

Hsync Polarity Is Positive

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.

Table XXIX. Vsync Detection Results

Detect

Function

No Activity Detected

Activity Detected

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 XXX. Active Vsync Results

Bit 5

(Vsync Detect)

Override

AVS

Bit 0 in 0EH

AVS = 0 means Sync separator.

AVS = 1 means Vsync input.

The override bit is in register 0EH, Bit 1.

Detected Vsync Output Polarity Status

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.

Table XXXI. Detected Vsync Output Polarity Status

Vsync Polarity Status

Result

Vsync Polarity Is Active High

Vsync Polarity Is Active Low

Sync-on-Green Detect

This bit is used to indicate when sync activity is detected

on the sync-on-green input pin, (Pin 49).

Table XXXII. Sync-on-Green Detection Results

Detect

Function

No Activity Detected

Activity Detected

The sync processing block diagram shows where this

function is implemented.

Detected COAST Polarity Status

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.

Table XXXIII. Detected Coast Input Polarity Status

Hsync Polarity Status

Result

Coast Polarity Is Negative

Coast Polarity Is Positive

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