Electronics > Projects, Designs, and Technical Stuff

Acute Logic & Lead CCTV PE-1005S HD Camera Module

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dexters_lab:

--- Quote from: CJay on November 19, 2019, 05:42:02 pm ---FWIW, I've found a few ADV7171 chips in my stash which look like, with fairly minimal effort, they'd take the 4:2:2 format signal from these and directly convert it to composite and component if anyone wants to try that

--- End quote ---

i don't think it would work, the output from the camera is not bt.601, it's a fixed output clock and a separate h & v sync signal with no SAV/EAV codes in the data so it's a bit more raw than 601/656

I would like a 601 compliant output TBH so i can get HD-SDI, i figured i'd let Ash get video output with HDMI  first before i start pestering him  :P

The other issue with HD-SDI is all the 656 to HD-SDI serialisers seem to be crazy expensive or are tiny BGA devices that are hard to work with

Yansi:
Why not encode and serialize the SDI directly in the FPGA and use just a cable driver after that?

//EDIT: First google result for a HD-SDI serializer + driver: LMH0340 (and less capable derivates). Nice package, but fuuuuuuuuck the price.  (but bearable price from the wild east)

OzOnE:
@Cjay - Yep, the ADV7513 accepts YCbCr as well, but as Mr Dexter said, the camera doesn't use a bt.601 / bt.656 style interface.

The ADV7171 also only has an 8-bit wide input bus, whereas the camera outputs 16-bit.

You could maybe feed the separate H/V syncs to the chip, but you'd still need a small CPLD to combine the Luma and Chroma samples first.

In theory, that would also get around the need to convert the pixel clock, as the ADV7151 would just output analog video.


@Yansi - We gave a fair bit of thought to adding SDI to the board, and I still might try that by encoding it on the FPGA itself.
I have some code from when we were trying that before, but I don't have any SDI stuff here to actually test it.

For very short cable runs, it might even work OK with just a cap for AC-coupling, but obviously a proper cable driver chip would be more ideal.

And yeah. The prices of the full SDI serializer chips is pretty steep. lol

OzOnE:
oic, I just glanced at the block diagram the other day, and only saw the "P7-P0" part. lol

So yeah, if it can handle Luma on bits 7:0, and interleaved Chroma on 15:8, then it might work OK.

Yansi:
So after seeing that this can indeed be worked out to functional state quite easily*, I have finally decided to buy a camera too.  Yaaay!   ^-^

*thought it would be much more troublesome, especially with the documentation.

Now I have some motivation to start doing FPGAs (instead of just CPLDs) and do something more complex with it then just blinkenlights.

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