01-03-2013 09:45 AM
Hello,now I design a custom board using cyclone IV EP4CGX15 to transfer video to our SOC.And now there is no on-board external RAM connected to FPGA,so I have to use on-chip memory. For I just transfer the video without any processing.can I connect the FrameBuffer's out to onchip-memory? It is said in the spec that the FrameBuffer buffers frame data to EXTERNAL RAM. For If I connect FrameBuffer---->onchio-FIFO(opt)---->SGDMA. Does this link have any problem? Thanks for any suggestions. Regards.
01-03-2013 01:00 PM
Socrates,Thank you very much!Sorry for I'm so newbie in FPGA,I'm not quite clear about your meanings. I think I didn't express our applications pretty clear. We want to use FPGA to act as a Bridge which sends raw video data to out SOC through PCIe. And use SGDMA to send video data to PCIe IP provided by altera. You mean that I should use a dual-port RAM? Just like "FrameBuffer--> DualPort RAM--->SGDMA“? Regards!
01-03-2013 04:25 PM
What is the resolution and bit depth of the video you want to frame buffer?Do you want a double or triple buffer? You will almost certainly not have enough on-board memory if you have video of any significant size. For instance, to triple buffer color video at VGA resolution, you would need a minimum of 24 (bits per pixel) * 640 (columns) * 480 (rows) * 3 (buffers) = 21,600 Kbits of embedded memory, which not even the largest Cyclone V devices are supporting. You will almost certainly need an external SDRAM or SRAM in order to frame buffer your video. --- Quote Start --- I'd offer to download framebuffer demo from alterawiki.com :) --- Quote End ---
01-04-2013 05:07 AM
Thank you gwall.The FrameBuffer write video buffer to RAM with address is added. I thought I can Link FrameBuffer to onchip FIFO in Qsys. It should be wrong.The FrameBuffer write data with the writing address is added after every write cycle,not write to a constant address. Thanks Socrates.Regards!