What Video Output Standard does the ADV728x Output in Free-Run Mode

Document created by Rob.Analog Employee on Mar 7, 2016
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This FAQ applies to the ADV7280, ADV7280-M, ADV7281, ADV7281-M, ADV7281-MA, ADV7282, ADV7282-M and ADV7283 models.

 

When an analog video source is disconnected from the ADV728x, the ADV728x will enter free-run mode ( it will output a blue screen or a test pattern).

 

However what video output standard will the ADV728x output in free-run mode?

 

1) When it enters free-run mode the ADV728x will output in the format of the last valid video source. i.e. if an NTSC source is disconnected from the ADV728x, then the ADV728x will output in a 480i in free-run mode.

 

2) If no video source has been connected to the ADV728x, then the ADV728x will default into outputting in a 576i format in free-run mode.

 

3) If the ADV728x has been programmed into progressive mode then the output from the ADV728x will be progressive. The above two rules also apply in this mode except that the output from the ADV728x will be progressive.

 

3) This default free-run mode format can be changed by setting the VS_COAST_MODE[1:0] bits ( User Submap, register 0xF9, bits [3:2]). Note that if a video source has been connected to the ADV728x then the VS_COAST_MODE bits will be ignored.

 

4) The user can force the output format output in free-run mode by setting the VID_SEL[3:0] bits. In this case the format last valid video source connected is ignored.

 

regards,

Robert Hinchy

Senior Applications Engineer,

Automotive Infotainment Group,

Analog Devices Inc.

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