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ADV7180: Video input looks distorted

Question asked by jerivera on Oct 9, 2012
Latest reply on Oct 11, 2012 by jerivera


I'm driving the input IN1 of the adv7180 with NTSC, from an op amp circuit driving a resistor divider,as the data sheet reccomends, and from the resistor divider ac couple to the input pin via a 0.1uF cap. When I probe the input pin the video signal looks distorted. I read the status registers via I2C and this what I get. STATUS1:6A, STATUS2: 00, STATUS3: 7C. There is no lock of any kind. I'm driving XTAL1 input with 1.8V oscillator @ 28.6363Mhz. The LCC output is 27Mhz. I'm using default values on the I2C registers. VSYNC is pulsing @ 18.8ms period and is asynhronous to the input. TV source is from a panasonic TV camera. Attached is a scope capture of the camera output and IN1 (pin 35) input. I'm using a 64 pin package. Do I have to set any other I2C registers? The part is set to autodetect NTSC by default.photo2.JPG