Why its pixel is 2 byte? i know its pixel can get a color .
I'm not sure I understand this question, but I think this is more concerned with the device specifics for the MT9P031 image sensor, and the PSoC forums may not be the place to ask.
From a quick look at the device datasheet, it has a 12 bit per pixel output. A byte is only 8 bits, so you need 2 bytes to make up 12 bits. (actually 16 bits, but you only use 12 of them).
If you need an 8 bit output from the sensor, then don't connect up the least significant bits 0-3. Only use bits 4-11. You'll lose brightness resolution, but you'll still get 256 levels per pixel.
Thank you so much ! Now i am concerned that my firmware's designed is wrong, I just need a 8 bits data,so i have to discard 4 bits data. I need to modify my USB desciption ,too. Do you have a firmware about MT9M114 sensor ,which can transfer raw data constantly. I need it ,if you have .
Sorry to say this is the first time I've even heard of the sensor! I've never actually implemented anything with an image sensor. Glad I was at least of some help though. Good luck.