(ADV7281AM)Can we delete "42 00 10 ; INSEL =unconnected input [INSEL Switch]"?

Hi !

I have a question.

Our customer are using ADV7281AM with full differential CVBS for automotive.

They are using this script.

**********************************************************************************

##07_CVBS DIFFERENTIAL FAST SWITCH ##

 :FAST SWITCH CVBS Differential In Ain1,2, MIPI Out:

delay 10 ; Wait 10ms After Hardware Reset To Start I2C

42 0F 80 ; Reset ADV7282A-M

delay 10 ; Wait 10ms

42 0F 00 ; Exit Power Down Mode [ADV7282M writes begin]

42 52 C0 ; Diff_CVBS AFE IBIAS

42 00 10 ; INSEL =unconnected input [INSEL Switch]

42 00 0E ; INSEL = CVBS_P in on Ain 1, CVBS_N in on Ain2

**********************************************************************************

Q1) 42 00 10; INSEL = unconnected input [INSEL Switch]

What does it exist for?

Q2) Can we delete "42 00 10; INSEL = unconnected input [INSEL Switch]"?

Q3) Is there any harm caused by deleting this script?

Our customer said when switching to the input to camera, there is a problem that a blue screen can be seen for a moment, and it seems that the unlocked state is falsely detected.

42 00 10; INSEL = unconnected input [INSEL Switch]

When they delete this script, their was no blue screen.

And there are no comment for this script at ADV728xAM documents.

There was a description in the document of the different device.

At ADV7182 RSD this is written.

Please refer to Note 1 after "Note" in the middle of theBest above.

The setting “42 00 10” is called “INSEL Switch”, and the lock time is accelerated in the case of differential input.

=>Described above as “Doing this optimizes the lock time of the ADV7182 in differential CVBS mode.

ADV7182 RSD

/cfs-file/__key/communityserver-discussions-components-files/331/5340.ADV7182RSD_5F00_revC.pdf

ADV7281AM Script

https://www.analog.com/media/en/engineering-tools/design-tools/ADV7281AM_Cust.zip

Best regards

Kawa

Parents
  • +1
    •  Analog Employees 
    on Jun 13, 2019 1:14 PM

    Hi Kawa,

    The INSEL write in question is necessary in the Fast Switch Script to achieve a Fast lock time ~250ms. This write is part of resetting the digital core to facilitate current clamp circuitry reset.  Without this write, the part will still achieve lock, but just not guaranteed within fast switch script time period.   And this is the benefit for using the fast switch script as opposed to auto-detect.

    When the write is not present, the decoder outputs a black screen likely as the input signal is below the range of low ADC code values but the same timing is used. When the write is present, and input switching is occurring the device knows to output a defined pattern screen for this duration, the color could also be configured the free run pattern control.

    Best Regards,

    David

Reply
  • +1
    •  Analog Employees 
    on Jun 13, 2019 1:14 PM

    Hi Kawa,

    The INSEL write in question is necessary in the Fast Switch Script to achieve a Fast lock time ~250ms. This write is part of resetting the digital core to facilitate current clamp circuitry reset.  Without this write, the part will still achieve lock, but just not guaranteed within fast switch script time period.   And this is the benefit for using the fast switch script as opposed to auto-detect.

    When the write is not present, the decoder outputs a black screen likely as the input signal is below the range of low ADC code values but the same timing is used. When the write is present, and input switching is occurring the device knows to output a defined pattern screen for this duration, the color could also be configured the free run pattern control.

    Best Regards,

    David

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