VIU FID-input purpose

[kef2]

Hello.

I wonder what's the purpose of FID input. RM and datasheet list it, but there's no description, except

• FID must change state 3 Hsync pulses into Vsync.

I don't understand ^^ it. Is there some timing diagram with specified time delays? Is FID signal required and limits sensor choice?

Also I wonder when

FIELD_IRQ and VSTART_IRQ interrupts are supposed to happen. I can't find information in RM.

Thanks

[naoumgitnik · Accepted solution]

Hello Edward,

• This signal is a part of a standard interface hence not described in our documentation (very briefly, it only indicates odd/even frame required for the de-interlacing feature).

• It is not mandatory, and the VIU interface actually works only based on Hsync and Vsync. If not provided to Vybrid, our VIU driver code (part of the BSP) should be modified - the FID input interrupt ignored, and its state is "do not care".

Regards, Naoum Gitnik.

[kef2]

Dead Naoum,

thank you very much for your reply. It answers my concern about FID pin usage, but I still have questions.

Which "standard interface" do you refer? While choosing sensors I saw different pin names used by different CMOS camera vendors. So at least they are not following standards for sync. signals names. I neither don't see any standards mentioned in VIU3 block 57.2 Features section. Could you specify what standard should I study, or maybe camera chip which documents FID and other "standard" signals?

It is also still not clear when FIELD_IRQ and VSTART_IRQ interrupts are supposed to happen. I lack at least short description for each VIU3 module interrupt.

You mentioned "our VIU driver code (part of the BSP)". Could you enlighten which BSP do you refer? MQX?

Thanks

[naoumgitnik]

Hello Edward,

I am not a video expert but would recommend to take a look at the following special-purpose component - NTSC/PAL/SECAM Video Decoder (http://www.mouser.com/ds/2/405/sles209e-205815.pdf). It has a similar interface (and the FID signal with description as well), and the ITU-R Recommendation BT.656, also called ITU656 ( formally  CCIR-656) is mentioned in it (see ITU-R BT.656 - Wikipedia, the free encyclopedia). Even in this brief description the Interlaced video technique is mentioned, relevant for the FID signal.

Hopefully it helps.

Regards, Naoum Gitnik.

[kef2]

Thanks.

I still would love to see FID input description in Reference Manual, along with description of VIU3 module interrupts.