Analog Devices Advantiv ADV7611 Hardware User's Manual page 115

Hardware User Guide
SYNC PROCESSED BY CP SECTION
The CP Core uses the HDMI section as its source of HSync, VSync and DE.
Sync Routing from HDMI Section
The CP section receives syncs from the HDMI section, as shown in Figure 40.
Signals Routing to Synchronization Channels
The ADV7611 has one synchronization channel consisting of one STDI section. When an HDMI input is applied, the HDMI core will
generate HSync, VSync, and DE signals and supply them as input to the each synchronization channel shown in Figure 40. HSync from
the HDMI block is denoted as HDMI_HS, and VSync from the HDMI block is denoted as HDMI_VS. DE from the HDMI block is not
shown in Figure 40 as it is passed directly to the CP core without any processing when an HDMI input is selected.
Standard Detection and Identification
As shown in Figure 40, the synchronization channel also contains standard detection and identification (STDI) block. These monitor the
synchronization signals to determine the video input standard.
The STDI blocks perform four key measurements:
•
Block Length CH1_BL[13:0]
This is the number of 28.6363 MHz clock cycles (XTAL frequency) in a block of eight lines. From this, the time duration of one line
can be concluded.
•
Line count in Field CH1_LCF[10:0]
The CH1_LCF[10:0] readback value is the number of lines between two VSyncs, that is, over one field measured by channel.
•
Line count in VSYNC CH1_LCVS[4:0]
The LCVS[4:0] readback value is the number of lines within one VSync period.
•
Field Length CH1_FCL[12:0]
This is the number of 28.6363 MHz clock cycles in a 1/256
length count in 28.6363 MHz (XTAL) clocks.
By interpreting these four parameters, it is possible to distinguish between the different types of input signals.
PRIM_MODE[2]
0
HS 1
HDMI HS 1
PRIM_MODE[2]
0
VS 1
HDMI VS 1
STDI 1
Figure 40. External/HDMI Syncs Routing to CP Section
POLARITY
CORRECTION
HS_GR_PC
VS_GR_PC
HS_PC
VS_PC
th
of a field. Alternately, this value of FCL multiplied by 256 gives one field
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TO SYNC MUX
TO SYNC MUX
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