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Syaoran74

Vmod+nexys 4

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Hi all,

 

I am a 4th year engineering student from RMIT university of Australia.

I'm in the search for FPGA board for the purpose of generating a depth map via stereo cameras, as part of a larger project.

What has caught my eye is the Nexys4-DDR board primarily for its Xilinx Artix-7 chip and upon further searching the Digilent store i so found the VmodCAM module which may be particularly useful for the project. 

However i am aware as to the fact that the Nexys4 board does not have a VHDCI port and hence would like to know of any work arounds to this issue, possible PMOD cameras or other ways to connect a pair of cameras to the Nexys 4 board.

 

Thank you for your time and assistance.

Edited by Josh
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Hi Syaoran74,

 

I have interfaced a cheap 640x480 camera to Zedboard and the Nexys-2, first using wire jumpers and then with a custom PCB (see http://hamsterworks.co.nz/mediawiki/index.php/Zedboard_OV7670).

 

Using the PCB was far superior - much more reliable. A camera requires 16 data signals and 2 power signals, so the physical positioning might need some experimenting. Maybe you can find a camera module on a flex-cable like http://www.aliexpress.com/item/Low-cost-24-pin-golden-finger-OV7670-micro-CMOS-camera-module-with-64mm-flex-for-mobile/1112059283.html, and then build an adapter?

 

However, using the VmodCAM on an Atlys board rather than the Nexys-4 might be more of a turn-key system (and the cameras are higher resolution too!).

 

Using cameras on an FPGA isn't just a plug-in-and-go sort of thing - they are far more complex than you initially think - colour spaces, pixel encoding, register settings...! They also need quite a bit of memory to hold images while you process them, so get prepared to learn all about the exciting world of interfacing FPGAs to DRAM.

 

Hope this helps!

 

Mike (who's just some random guy from the internet, not from Digilent BTW)

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Hi Syaoran74, actually, Digilent partner in China provided Pmod camera solutions from 0.3Mb to 5Mb. 

 

Here is the link. 

 

http://www.digilentchina.com/product-more.asp?ClassId=21&Unid=806

http://www.digilentchina.com/product-more.asp?ClassId=21&Unid=807

http://www.digilentchina.com/product-more.asp?ClassId=21&Unid=810

 

Unfortunately it is in Chinese. Take a look. You can purchase those Pmods from them. 

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Thank you Hamster for your insights, i am not to familiar with the Zedboard or even building the necessary connections for an adapter, hence looking for the most simple setup such as the VmodCam, i also have looked into the Atlys board but im being advised by the supervisor to stay with the Artix-7 over the older Sparten-6s.

I'm also starting to learn VHDL and Verilog to program these FPGA and i'd like to try incorporate your code into the project when i understand it more. 

 

Alex i will definitely pass this on to a friend who can hopefully read this, however it looks very promising. espically the 0.3MP unit as this is the resolution and framerate we were looking at using.

 

Else if the Nexys 4 board is unable to support these cameras, the supervisor is really pushing for the Xilinx Evaluation board but it is very costly or perhaps use a DSP as bridge between the camera and the Nexys 4 as the project will also require a DSP. Hence i'd also like to ask how would i go about connecting the Nexys 4 to a DSP?

 

Thank you again.

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I've got a few spare PCBs around that can connect two PMOD sockets to a module like this: http://www.dx.com/p/ov7670-300kp-vga-camera-module-for-arduino-147742. If you private message me your address I can send you two in an envelope. You will just need to track somebody down to to solder the through-hole 0.1" pitch headers, and of course purchase your camera modules (it would be wise to get a spare too)

 

If you want, I could see if I can find some 2x6-way right-angle 0.1" headers. That way both cameras might end up pointing in the same direction (looking up from the board) without the use of cables. The only problem would be that they will be at 180 degrees to each other. It isn't that bad as you can set the 'flip the image' register in the camera...

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I've got a few spare PCBs around that can connect two PMOD sockets to a module like this: http://www.dx.com/p/ov7670-300kp-vga-camera-module-for-arduino-147742. If you private message me your address I can send you two in an envelope. You will just need to track somebody down to to solder the through-hole 0.1" pitch headers, and of course purchase your camera modules (it would be wise to get a spare too)

That sounds great Hamster thank you for your generosity, however i will need to ask my supervisor if he wants to go down this path, so perhaps if you could send the design for your pcb we can get it made up if we end up using this idea. also if we did, i think we'd still need to use a cable to connect the cameras as the 2 pairs of of pmod headers are connected to the opposite ends of the board and for stereo imaging you need the two to be together

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