User guide

Chapter 10: Clocked Video Input MegaCore Function 10–3
Functional Description
January 2013 Altera Corporation Video and Image Processing Suite
User Guide
Table 10–2 lists the signals and Figure 10–3 shows the timing.
Video Locked Signal
The vid_locked signal indicates that the clocked video stream is active. When the
signal has a value of 1, the Clocked Video Input MegaCore function takes the input
clocked video signals as valid and reads and processes them as normal.
When the signal has a value of 0 (if for example the video cable is disconnected or the
video interface is not receiving a signal) the Clocked Video Input MegaCore function
takes the input clocked video signals as invalid and does not process them.
If the
vid_locked signal goes invalid while a frame of video is being processed, the
Clocked Video Input MegaCore function ends the frame of video early.
Control Port
If you turn on Use control port in the parameter editor for the Clocked Video Input,
its Avalon-ST Video output can be controlled using the Avalon-MM slave control port.
Initially, the MegaCore function is disabled and does not output any data. However, it
still detects the format of the clocked video input and raises interrupts.
The sequence for starting the output of the MegaCore function is as follows:
1. Write a 1 to
Control register bit 0.
Table 10–2. Clocked Video Input Signals for Separate Synchronization Format Video
Signal Name Description
vid_datavalid
When asserted the video is in an active picture period (not horizontal or
vertical blanking).
vid_h_sync When 1, the video is in a horizontal synchronization period.
vid_v_sync When 1, the video is in a vertical synchronization period.
vid_f
When 1, the video is interlaced and in field 1. When 0, the video is either
progressive or interlaced and in field 0.
Figure 10–3. Separate Synchronization Signals Timing
vid_datavalid
D0 DNvid_data D1 Dn+2Dn+1
vid_v_sync
vid_h_sync
vid_f