1. Yes, you can directly connect the Image sensor to the FX3. Frame skip will happen if the host is slow enough to read the data from the FX3 buffers. This happens generally when you stream very high resolution. For high resolution streaming, the Image sensor will send continuous data to the FX3 and if the host controller is not fast enough to read the data, it may cause frame loss. However we have tested till 1080p@60 fps using FX3. What is the resolution that you want to stream? You can refer to the following application note for getting started(http://www.cypress.com/documentation/application-notes/an75779-how-implement-image-sensor-interface-using-ez-usb-fx3-usb) .
2. Or as another option, you can also use an FPGA between the image sensor and the FX3. In this case you can use the Slave FIFO interface between the FPGA and the FX3. Refer to the following application note regarding this(http://www.cypress.com/documentation/application-notes/an65974-designing-ez-usb-fx3-slave-fifo-interface). We do not have any example regarding the interface between the image sensor and the FPGA.
I am now using fx3 Explorer kit and ov5642 but black screen appears. Did you succeed in it?
Did you add the sensor configuration for OV5642? In AN75779 we have provided added the sensor configuration for MT9M114 (ON Semiconductor). Please verify that your sensor is configured properly. Check the FV/LV signals on the interface using oscilloscope to check if the sensor is providing the data. Next check for the PRODs event in the DMA callback to make sure whether the FX3 is receiving the data on the GPIF. Please check the descriptors and the probe control settings, the default AN75779 firmware is written for 720p at 30 fps and VGA at 15. So, please make sure that the sensor and the firmware is configured for the correct setting which the sensor is expected to generate.
Why don't you response the my question about the reset the slavefifo firmware? The cypress does not any more support? I want to kmow what kinds of reset methods are existed in the slavefifo firmware. And also GPIF. Especially, my problem is that fx3 fallin in hang problem , if I tried to transfer data with not 1024 data length, then the fx3 does not response until push the reset button. I want to know if the fx3 got problem what those kind of, how can I make to normal state?