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USB Superspeed Peripherals

KeWa_2323766
New Contributor II

UVC based application for FX3 is created based on the framework of AN75779.  24bit GPIF is used(D23:D0) . image is 800*600.  Pixel depth is 24bit/pixel, i.e. 3Byte/pixel.  Since it is 24bits/pixel raw image, GUID for RGB888 is used for media type and RGB888 will be debayered in host.   DMA buffer keeps the same: 16kB, 4 counts, 2 sockets.  Only change the GPIF bus to 24bits, LD_DATA_COUNT, LD_ADDR_COUNT to 5455. However, it can't stream. 

But according to KBA226722,  

S= 800*600*3= 1,440,000 byte,

F= int(S/(16384-16))= 1440000/16368 = 87

P= fraction of S/(16384-16) * 16368 = 0.976594*16368 = 15984

It should be working. 

I noticed that in KBA226722 , it mentioned in item 5 "If exact line data (i.e nothing is appended at the end of the line data) is intended to be sent to the Host, then make sure that line size in bytes is divisible by GPIF bus width (in bytes)."  I don't quite get this point. 

Help is needed on the proper  setting of DMA configuration and GPIF state machine data and address count value. 

Thanks in advance

 

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Hemanth
Moderator
Moderator

Hi Kelly,

Do you see commit buffer failures with VirtualDub and eCamview?

You can also try with MPC-HC player.

Regards,

Hemanth

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