GS1531 Data Sheet
4.5 Data-Through Mode
The GS1531 may be configured by the application layer to operate as a simple
parallel-to-serial converter. In this mode, the device presents data to the output
buffer without performing any scrambling or encoding.
Data-through mode is enabled only when both the SMPTE_BYPASS and
DVB_ASI pins are set LOW.
4.6 Additional Processing Functions
The GS1531 contains an additional data processing block which is available in
SMPTE mode only, see SMPTE Mode on page 25.
4.6.1 Input Data Blank
The video input data may be 'blanked' by the GS1531. In this mode, all input video
data except TRS words are set to the appropriate blanking levels by the device.
Both the horizontal and vertical ancillary data spaces will also be set to blanking
levels.
This function is enabled by setting the BLANK pin LOW.
4.6.2 Automatic Video Standard Detection
The GS1531 can detect the input video standard by using the timing parameters
extracted from the received TRS ID words or supplied H, V, and F timing signals,
see Internal Flywheel on page 25. This information is presented to the host
interface via the VIDEO_STANDARD register (Table 4-2).
Total samples per line, active samples per line, total lines per field/frame and active
lines per field/frame are also calculated and presented to the host interface via the
RASTER_STRUCTURE registers (Table 4-3). These line and sample count
registers are updated once per frame at the end of line 12. This is in addition to the
information contained in the VIDEO_STANDARD register.
After device reset, the four RASTER_STRUCTURE registers default to zero.
Table 4-2: Host Interface Description for Video Standard Register
Register Name
Bit
Name
Description
R/W
Default
VIDEO_STANDARD
Address: 004h
15
–
Not Used.
–
R
R
–
0
0
14-10
9
VD_STD[4:0]
INT_PROG
Video Data Standard (see Table 4-4).
Interlace/Progressive: Set LOW if detected video
standard is PROGRESSIVE and is set HIGH if it is
INTERLACED.
8
STD_LOCK
–
Standard Lock: Set HIGH when flywheel has
achieved full synchronization.
R
–
0
–
7-0
Not Used.
30573 - 4 July 2005
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