Displaying a picture on VGA

[JacquesKleynhans]

HI All,

I would like to know if its possible to display a picture of say 5mp from nand flash through VGA to screen without using SRAM or other kind of ram for buffer.

THX

 

[farhada]

Is the image fully de-compressed? In the case the bandwidth of your memory needs to be more than 640x480x60x3 (assuming you mean VGA resolution) bytes per second. If you have flash memory fast enough for this, you can do this, otherwise, you need a fast memory to save the data from the flash or you need to save the image in compressed format and implement the image coding inside the FPGA.

Hope this helps.

 

[JacquesKleynhans]

Yes it helped thx, just supporting my thoughts.

I was trying to avoid using sram in my design but it seems I am going to have to implement a fifo at least. I am building a camera system for a small satellite and the VGA was considered for prelim testing. But I will maybe consider just sensing the data from the memory out through serial connect tp pc for initial testing.

THe problem that I am faced with is the camera sensor has a full resolution of 5mp thus having image size of 2592 x 1944 and the page depth of my nand flash is 1024 word. So I have basically thought about 2 things 1. reduce the image size to fit within the page width or add a FIFo to buffer the image then write it to the nand device.

the second one will mean I have to reduce the camera clock to a measly 1 Mhz to create a sufficiant delay to complete 2 write cycles of the memory with takes about 220 us each.

So im in a quite a situation. One hand I want full res photos but on the other I want to avoid sram because of radiation issues and the accompany blocks like ecc and such.

Thx

 

[farhada]

Hi,
You are welcome, it is interesting what you are planning to do, but I have problem understanding the exact application here.

You want to capture the data from a 5MP camera into the FPGA and save it on a Flash EEPROM? I don't know of any Flash that has enough bandwidth for such application.

Also, if you are afraid of SRAM for radiation (are you sure you mean SRAM and not SDRAM?), then you should consider the problem with the FPGA's internal structure as well, most FPGAs today are SRAM based and sensitive to radiation unless you go for some VERY expensive devices that are classified for high radiation applications.

Best regards,
/Farhad

 

[JacquesKleynhans]

Hi, Yes the project im working on is for masters thesis project. I am using actel flash based FPGA with peripheral nand flash memory. There is a very small amount of sram onboard the fpga which im thinking about using to buffer the row pixels coming from the camera sensor.

Our university is building a little cubesat and I have the pleasant task of building the camera and data routing system.

 

[farhada]

Ok, that explains it. Thanks.
It will be a difficult task to put the data into an external flash without compression, maybe you should look into simple compression such as GIF or something to make the image smaller.

 

[JacquesKleynhans]

Hi, Yes I will have some image compression running. As soon as I get basic functionality going I will work on the compression routine. As all of this is pretty new to me I still have to do bit of research

 

[framer]

hi, look at http://www.3d-plus.com/product.php?type=1 and **broken link removed**.