Figure 88: Stdi Vertical Locking Operation; Figure 89: Stdi Vsync Monitoring Operation - Analog Devices Advantiv ADV7604 Hardware Manual

10.8.3.2 STDI Vertical Locking
The STDI block compares adjacent field length differences and VSync lengths in line counts and
compares them with a threshold. If four consecutive adjacent field lengths (LCF) and line counts in
VSync (LCVS) are within the threshold, the STDI vertically locks to the incoming video.
Field1 – Field2 ≦threshold? Field1 – Field2 ≦threshold?
Field1 Field1
Active Video Active Video
Active Video Active Video
Vsync1 Vsync1
Vsync1 – Vsync2 ≦threshold? Vsync1 – Vsync2 ≦threshold?
Once the STDI locks to the incoming video, the STDI registers the latest field length/VSync length
as latched data (absolute field length: F, absolute VSync length: V). The STDI keeps monitoring
and comparing Field/VSync lengths with the respective absolute length (F, V) once vertically
locked. The STDI vertically unlocks if four consecutive Field or VSync lengths are greater than the
respective threshold.
Field1 Field1
Active Video Active Video
Active Video Active Video
Vsync1 Vsync1
CH1_BL[13:0], Block Length for channel 1 Read Back , CP Map, Address 0xB1, [5:0]; Address
0xB2, [7:0]
Function
CH1_BL[13:0]
xx xxxx xxxx xxxx
Rev. F August 2010
Field2– Field3 ≦threshold? Field2– Field3 ≦threshold?
Field3 – Field4 ≦threshold? Field3 – Field4 ≦threshold?
Field2 Field2 Field3 Field3
Active Video Active Video
Vsync2 Vsync2
Vsync2 – Vsync3 ≦threshold? Vsync2 – Vsync3 ≦threshold?

Figure 88: STDI Vertical Locking Operation

Field2 Field2 Field3 Field3
Active Video Active Video
Vsync2 Vsync2

Figure 89: STDI VSync Monitoring Operation

Description
Number of 28.6363 MHz (XTAL frequency) cycles in a block of eight
lines of incoming video. Data only valid if
high.
Field4 – Field5 ≦threshold? Field4 – Field5 ≦threshold?
Field4 Field4
Active Video Active Video
Vsync3 Vsync3
Vsync4 Vsync4
Vsync3 – Vsync4 ≦threshold? Vsync3 – Vsync4 ≦threshold?
Vsync5 – Vsync4 ≦threshold? Vsync5 – Vsync4 ≦threshold?
F F
Latched Field Length Latched Field Length
Field4 Field4
Active Video Active Video
Vsync3 Vsync3
Vsync4 Vsync4
F F
Latched Vsync Length Latched Vsync Length
CH1_STDI_DVALID
272
Field5 Field5
Active Video Active Video Active Video Active Video
Vsync5 Vsync5
Field5 – F ≦threshold? Field5 – F ≦threshold? Field6 – F ≦threshold? Field6 – F ≦threshold?
Field5 Field5
Active Video Active Video Active Video Active Video
Vsync5 Vsync5
Vsync5 – V ≦threshold? Vsync5 – V ≦threshold?
ADV7604
Field6 Field6
Field6 Field6
is