ADV7181 datasheet(21/96 Pages) AD

21 / 96 page

ADV7181B

Rev. 0 | Page 21 of 96

AD_SECAM_EN Enable Autodetection of SECAM,

Address 0x07 [6]

Setting AD_SECAM_EN to 0 (default) disables the

autodetection of SECAM.

Setting AD_SECAM_EN to 1 enables the detection.

AD_N443_EN Enable Autodetection of NTSC 443,

Address 0x07 [5]

Setting AD_N443_EN to 0 disables the autodetection of NTSC

style systems with a 4.43 MHz color subcarrier.

Setting AD_N443_EN to 1 (default) enables the detection.

AD_P60_EN Enable Autodetection of PAL60,

Address 0x07 [4]

Setting AD_P60_EN to 0 disables the autodetection of PAL

systems with a 60 Hz field rate.

Setting AD_P60_EN to 1 (default) enables the detection.

AD_PALN_EN Enable Autodetection of PAL N,

Address 0x07 [3]

Setting AD_PALN_EN to 0 (default) disables the detection of

the PAL N standard.

Setting AD_PALN_EN to 1 enables the detection.

AD_PALM_EN Enable Autodetection of PAL M,

Address 0x07 [2]

Setting AD_PALM_EN to 0 (default) disables the autodetection

of PAL M.

Setting AD_PALM_EN to 1 enables the detection.

AD_NTSC_EN Enable Autodetection of NTSC,

Address 0x07 [1]

Setting AD_NTSC_EN to 0 (default) disables the detection of

standard NTSC.

Setting AD_NTSC_EN to 1 enables the detection.

AD_PAL_EN Enable Autodetection of PAL,

Address 0x07 [0]

Setting AD_PAL_EN to 0 (default) disables the detection of

standard PAL.

Setting AD_PAL_EN to 1 enables the detection.

SFL_INV Subcarrier Frequency Lock Inversion

This bit controls the behavior of the PAL switch bit in the SFL

(GenLock Telegram) data stream. It was implemented to solve

some compatibility issues with video encoders. It solves two

problems.

First, the PAL switch bit is only meaningful in PAL. Some

encoders (including Analog Devices encoders) also look at the

state of this bit in NTSC.

Second, there was a design change in Analog Devices encoders

from ADV717x to ADV719x. The older versions used the SFL

(GenLock Telegram) bit directly, while the later ones invert the

bit prior to using it. The reason for this is that the inversion

compensated for the 1-line delay of an SFL (GenLock Telegram)

transmission.

As a result, ADV717x encoders need the PAL switch bit in the

SFL (GenLock Telegram) to be 1 for NTSC to work. Also,

ADV7190/ADV7191/ADV7194 encoders need the PAL switch

bit in the SFL to be 0 to work in NTSC. If the state of the PAL

switch bit is wrong, a 180° phase shift occurs.

In a decoder/encoder back-to-back system in which SFL is used,

this bit must be set up properly for the specific encoder used.

SFL_INV Function Address 0x41 [6]

Setting SFL_INV to 0 makes the part SFL-compatible with

ADV7190/ADV7191/ADV7194 encoders.

Setting SFL_INV to 1 (default) makes the part SFL-compatible

with ADV717x/ADV7173x encoders.

Lock Related Controls

Lock information is presented to the user through Bits [1:0] of

the Status 1 register. See the STATUS_1[7:0] Address 0x10 [7:0]

section. Figure 8 outlines the signal flow and the controls

available to influence the way the lock status information is

generated.

TIME_WIN

FREE_RUN

STATUS 1 [0]

SELECT THE RAW LOCK SIGNAL

SRLS

FILTER THE RAW LOCK SIGNAL

CIL[2:0], COL[2:0]

TAKE FSC LOCK INTO ACCOUNT

FSCLE

STATUS 1 [1]

FSC LOCK

COUNTER INTO LOCK

COUNTER OUT OF LOCK

MEMORY

Figure 8. Lock Related Signal Path

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