fx3 uvc with sensor ov7675 not working

Anonymous · ‎Oct 06, 2017

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

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

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?

Anonymous · ‎Oct 13, 2017

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()

which will result in system crash.

Re: fx3 uvc with sensor ov7675 not working