A multi register control does not appear to have any effect?

Document created by Patrick.Aherne on Oct 18, 2010
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Question: I have tried adjusting the Hsync position on the ADV7401 using the HSB & HSE controls. However i see no effect looking at the outputs on my scope?


Answer: The controls we are referring to are spread over multiple I2C registers. Hence you must adjust the control registers in sequence with no other I2C commands in between. If you are using the ADV register control as a GUI we recommend you use "Special" > "Multi register Bits" function as a means to adjust the H Sync position. This is most likely the problem if you see no effect when adjusting controls spread over multiple register locations.