I have now faced with a problem, the main problem is the output of the ADV212 is abnormal, but the SCOM[0:3] changes high and low, dreq0 also asserts periodically, in one word, everything seems normal,but the output is not normal???? some expert gives me help????
the video is generated in FPGA ,i wrote striples as the video , and i made the changing edge of vsync and hsync not at the same clock ,to avoid them changing simultanously, the size of the video is 500(horizl) X 1000(verti) ,active video is 480 X 640 ,this meets the requirement of 6 lines and 16pixels .
the configuration of the device is also successful,cause the dreq0 asserts . i use the DMA burst 16bit read out. when output to the computer using RS232 , the data doesn't contain Head mark (FF4F) and end mark(FFD9),and anyother marker at all, but the scom4(indicating read out of the end of the frame) keeps being high, when it is not yet being high ,the RS232 just read out 000000, and when it changes high , the data begins ,but not the right data????? pls give some help , every answer is appreciate.
part of the output is attached,