hblnk
actvid
hsync
vblnk
vsync
G
ro
u
p
1
Gr
o
up 2
Internal Modules
172
SPRUHI7A – December 2012 – Revised June 2016
Copyright © 2012–2016, Texas Instruments Incorporated
High-Definition Video Processing Subsystem (HDVPSS)
1.2.8.2.18 Discrete Sync Signals
External ICs generally produce discrete sync interface signals seen in
Figure 1-120. Discrete Sync Interface Signals
vbnk
represents the vertical blanking interval. Generally, vertical blanking is at the top of a NTSC/PAL
field. In certain standards, the last few lines of a field or frame are in vertical blanking in addition to the
beginning few lines in the following field or frame.
v
sync
is the vertical sync indicator. vsync is active during a portion of the vertical blanking. Generally,
vsync is defined to transition from inactive to active sometime during vertical blanking. This signal then
transitions to an inactive state before the end of vertical blanking. Certain standards define the line
numbers where vsync transitions.
hblank
is the horizontal blanking interval for each line. The horizontal blanking is the same number of
pixels whether the line is in the active video region or in the vertical blanking region of the scan.
actvid
is the region of a line that is active video. It is exactly inverse of the hblank signal. The number of
pixels in the actvid region is the same for a line in vertical blanking as a line in active video.
hsync
transitions from inactive to active for the first pixel of each line, which is a horizontal blanking pixel.
hsync will transition to the inactive state before the end of the line.
Group 1
signals define the vertical separation between fields or frames. Group 2 signals define the
separation between lines. Note that the VIP module defines three discrete sync control signals: Actvid,
Hsync, and Vsync. One of the Group 1 signals can be tied to the Vsync input. The Actvid signal from
Group 2 is tied to the Actvid input. One of the other two Group 2 signals, hblank or hsync, can be tied to
the Hsync input.
USE_ACTVID_HSYNC_N
defines whether the line separation method uses the signal from the ACTVID or
the HSYNC input of the VIP module. DISCRETE_BASIC_MODE determines whether discrete sync works
as described in
. In summary, choose one signal from Group 1 and one signal from
Group 2. There should be a way to capture the external data.