Generation of the video timing output signals can be synchronized to the detected video
timing input signals or generated independently by setting the
SYNC_ENABLE field in the Control Register or selecting the GUI
option to synchronize the generator to detector or fsync_in.
Synchronization allows the generator to follow the phase of the detector timing.
Synchronization of the output to the input allows the developer to override each
individual timing signal with different settings such as signal polarity or start time.
For example, the active video signal could be regenerated shifted one cycle earlier or
later. This provides a flexible method for regenerating video timing output signals with
different settings while remaining synchronized to the input timing.
The VTC also has a GUI parameter, called Auto Generation Mode, to control the behavior of the generated outputs based on the detected inputs. When the Auto Generation Mode parameter is set, the generated video timing outputs change based on the detected inputs. If this parameter is not set, the video timing outputs generate based on only the first detected input format (if the detector loses lock, the generated outputs continue to generate). To change output timing while Auto Generation Mode is set, timing detection must first be disabled by clearing bit 1 in the Control Register and then re-enabling, if any of the Source Select bits are Low.