Electronics > Projects, Designs, and Technical Stuff

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

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PlainName:
Sounds brill :)

dexters_lab:
quick update,

ElectronAsh has been working on a PCB for this just to get something up and running, it's essentially FPGA and HDMI as that is what Ash works with all the time. The camera is mounted directly on the PCB to save the expense of a flat flex.

He's just about to order a few of these boards and will be doing all the work on the FPGA, funding the PCBs and component purchase himself, so we can't thank him enough! Those of us interested in getting these cameras working should consider helping him out with some extra funds as things progress.

PlainName:
Happy to chip in, within reason. Is he going to flog the completed boards or what?

OzOnE:
Hi,

Firstly, a big thanks to Mjolinor for offering the cameras, and sending me a few. Very generous of you.


It's going to be tricky for me atm to get a batch of boards assembled by a company, mainly due to finances and time, as I'm working on many different projects atm.

I'm hoping to build two or three boards first, then confirm they work OK. I don't like to release anything until it's tested obviously.

I've tried to double-check what I can on the design, like the measurements for the header to the cam module, distances for the mounting holes, supply rails for the FPGA IO banks, which pins on the cam module needed pull-ups or tied to GND/VCC etc.

This is my first project using the MAX10, though, so that may require a few tweaks if I've missed something.

My usual go-to FPGA has been the Cyclone III for the past 4-5 years, as it can still be bought in the TQFP144 package for manual soldering. I've yet to get my reflow oven up-and-running so I can start using BGA stuff.

The MAX10 does have a fair few advantages. It frees up more IO pins (and every one is precious. lol), does away with one or two extra voltage regs, since it can run on a single 3V3 supply, and obviously it doesn't require external SPI Flash for configuration, so there's a slight saving there.

I'll be sending off for say 5 PCBs via PCBway in the next day or two, but I've been trying to get a couple of other designs done in the mean time, so I can get them shipped all at once.

If I don't manage to finish the other designs by about the weekend, I'll just order the 5 camera board PCBs, then build a few myself.


I've used the ADV7513 HDMI chip in many previous projects, and it's used on dev boards like the Terasic C5G and DE10 Nano / MiSTer.

The main challenge with the camera modules is that they apparently have a fixed pixel clock output of 66 MHz. Rather than having to buffer a full frame (requiring a larger FPGA and external RAM), I'm hoping to just use line buffers on the FPGA to get some image output via HDMI.

What I didn't quite get at first, is how the camera manages to output 1080p with pixel clock of only 66 MHz.

It should in theory be outputting one Luma sample per clock, and of course a Cb or Cr sample on every alternate clock.
But that still didn't seem to be a high enough pixel clock for 1080p?

And then Mr Dexter reminded me that it's 1080p at a max of 30 FPS. lol

So yep, the usual pixel clock for 1080p 60Hz via HDMI is 148.5 MHz, and 30Hz (or 1080i@60hz) would only be around 74.25 MHz.

Plus, I don't think the datasheet for the cam includes the blanking intervals in that spec, so 66 MHz should be plenty of bandwidth for the active pixels / lines.

In summary - a full framebuffer hopefully won't be required for generating the HDMI output, and making the most of the cam module, but we'll see.


P.S. ElectronAsh == OzOne.

OzOnE:
btw, the PCB will be 2-layer for now.

tbh, 4-layer PCBs don't cost a huge amount more these days, but I don't think it's really necessary for this board. Although, it would probably have made the routing a fair bit easier. lol

(I prefer to use Eagle for the small-ish projects, as I'm still learning to use things like the library editor on Altium. I've been using Eagle for about ten years now, and just find it a lot quicker to get projects started on. For anything more complex, like multi-layer boards, I can import Eagle projects into Altium quite easily. Altium is a lot nicer for routing multi-layer stuff.)

I have done some estimates on the power dissipation of the voltage regs on the cam board, but will be adding some copper pours to act as heatsinks on some of them.

I'm running all three voltage regs (3V3, then 2V8 + 4V0 for the cam) from the 5V input atm.

As Mr Dexter said in a previous post, the cam is said to draw around 450ma (for the motors) on the 4V rail, and 270ma on the 2V8 rail.

I don't expect the FPGA and HDMI chip to draw much more than around 150mA from the 3V3 reg.

Realising that there wouldn't be much of a voltage drop from 5V to 4V (for the cam motor supply), I changed from using the LM1117 to the TLV75801, which has a low-dropout of only around 130mA...

https://www.ti.com/store/ti/en/p/product/?p=TLV75801PDBVR

All three regs will be in a SOT-223 package.


If anyone could help calculate the rough power dissipation for those (all with a 5V input), that would help a lot, since I struggle a bit with that stuff.

I can add copper pours on both the top and bottom layers for the three regs, with some connecting vias around the "tabs".

I think it'll be OK with a bit of copper added for heatsinking. Failing that, it is essentially just a test board atm, so we could stick on some small heatsinks if need be.

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