Fast Switch Mode

Document created by Rob.Analog Employee on Nov 7, 2013Last modified by Rob.Analog Employee on Jun 23, 2014
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This FAQ relates to the ADV7182, ADV7280, ADV7280-M, ADV7281, ADV7281-M, ADV7281-MA, ADV7282 and ADV7282-M video decoders. These video decoders will be referred to as ADV7182/728x in this FAQ.

 

Under certain circumstances users of the ADV7182/728x may wish to switch from one analog input to another quickly. This is particular true in automotive applications where the demand to switch inputs in 'a blink of an eye'  (i.e. approximately 250 ms) is usual.

 

Using standard scripts it may sometimes take the ADV7182/728x longer than 250 ms to switch from one (single ended or differential) CVBS input to another (single ended or differential) CVBS input. For this reason fast switch scripts were created.

 

Fast switch mode allows the ADV7182/728x video decoders to lock to single-ended CVBS or differential CVBS video in under 250 ms.

 

There are some drawbacks to using the fast switch script:

1) In fast switch mode the ADV7182/728x is not robust to Macrovision (Rovi) signals.

2) In fast switch mode the ADV7182/728x is not robust to poor and non-standard video sources.

3) Analog Devices does NOT advise any deviation from the advised fast switch scripts. Deviation from these devised fast switch scripts may introduce uncertainty.

 

It should be noted that Autodetect still works in fast switch mode for the ADV7182/728x.. However only NTSC M/J, NTSC 4.43 and PAL I/B/G/D can be detected. If a different video standard is used then the user must manually program it using the VID_SEL bits (User Map, Register 0x02 btis [7:4]).

 

The fast switch mode scripts are within the script files which are available at the design support files websites. See links below.

ADV7182 design support files http://ez.analog.com/docs/DOC-2633

ADV7280/ADV7280-M design support files http://ez.analog.com/docs/DOC-10612

ADV7281/ADV7281-M/ADV7281-MA design support files http://ez.analog.com/docs/DOC-10649

ADV7282/ADV7282-M design support files http://ez.analog.com/docs/DOC-10650


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