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USB Superspeed Peripherals

Anonymous
Not applicable

Hi all

   I am working on CYUSB3KIT-003 kit with image sensor ov7675 currently, and using AMCap on PC

   I follow the instruction AN75779, and made some modify with the previous discussion

   Re: Cypress EZUSB FX3 to stream video from OV7670

   AN75779 modification - FX3 for streaming image sensor data

    Hardware setting:

    ov7675 is initialized by another device, so i2c function on fx3 is disabled

    only connect DQ[0-7]  PCLK  FV  LV to fx3

   since ov7675 default resolution is 640*480 so I connect the fx3 to usb 2.0 port on PC,

   according to the  AN75779, the uvc will switch to 640*480 automatically, and AMCap recognize this as well

  I enable the #define DEBUG_PRINT_FRAME_COUNT to check the status of frame receiving

  and using oscilloscope to check the FV and LV existing, and it does

  but i can't see any image on AMCap

  the debug info:

     most of the time:

     UVC: Completed 0 frames and 0 buffers

     UVC: Completed 0 frames and 0 buffers

     UVC: Completed 0 frames and 0 buffers

     UVC: Completed 0 frames and 0 buffers

    sometimes:

   Application Started

   UVC: Completed 0 frames and 0 buffers

   UVC: Completed 175 frames and 0 buffers

   UVC: Completed 363 frames and 0 buffers

   UVC: Completed 528 frames and 0 buffers

   UVC: Completed 727 frames and 0 buffers

   UVC: Completed 898 frames and 0 buffers

   UVC: Completed 1065 frames and 0 buffers

   UVC: Completed 1221 frames and 0 buffers

   UVC: Completed 1421 frames and 0 buffers

   UVC: Completed 1583 frames and 0 buffers

   DMA Reset Event: Commit buffer failure

   Application Stopped

  is anyone encounter the same problem?

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1 Solution
Anonymous
Not applicable

Hi all

  Finally I got it work. It turns out the PCLK signal problem. I just change a way to connect PCLK between sensor and FX3

  However I can't tell the different of PCLK between two connection ways on oscilloscope.

  By the way, during the debugging I add debug message in: uvc.c function CyFxUvcApplnDmaCallback()

擷取.JPG

which will result in system crash.

View solution in original post

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2 Replies
Anonymous
Not applicable

Hi all

  Finally I got it work. It turns out the PCLK signal problem. I just change a way to connect PCLK between sensor and FX3

  However I can't tell the different of PCLK between two connection ways on oscilloscope.

  By the way, during the debugging I add debug message in: uvc.c function CyFxUvcApplnDmaCallback()

擷取.JPG

which will result in system crash.

View solution in original post

0 Likes
Anonymous
Not applicable

Hi,

You are not commended to add Debug Prints in the DMA Callback for every buffer. It adds too much overhead. DMA Callbacks ger triggered more quickly than debug data is sent over UART,

So, if you want to print statistics of buffers, you do it at certain intervals (for example, print after  every20 buffers or print at the last buffer of the frame (short buffer) .

Regards,

- Madhu Sudhan