Figure 92: Stdi Vertical Locking Operation; Figure 93: Stdi Vsync Monitoring Operation - Analog Devices ADV7850 Hardware Manual

Field1 – Field2 ≦threshold? Field1 – Field2 ≦threshold?
Field1 Field1
Active Video Active Video
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
Vsync1 Vsync1
ch1_bl[13:0], Addr 44 (CP), Address 0xB1[5:0]; Address 0xB2[7:0] (Read Only)
This readback displays the block length for sync channel 1. It displays the number of crystal clock cycles in a block of eight lines of
incoming video. This readback is valid if ch1_stdi_dvalid is set to 1.
Function
ch1_bl[13:0]
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ch2_bl[13:0], Addr 44 (CP), Address 0x49[5:0]; Address 0x4A[7:0] (Read Only)
This readback displays the sync channel 2 block length. It displays the number of crystal cycles in a block of eight lines of incoming
video. The readback is valid if ch2_stdi_dvalid is set to 1.
Function
ch2_bl[13:0]
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ch1_lcvs[4:0], Addr 44 (CP), Address 0xB3[7:3] (Read Only)
This readback displays the sync channel 1 line count in a VSync. It displays the number of lines in a VSync period measured on sync
channel 1. The readback is valid if ch1_stdi_dvalid is set to 1.
Rev. A May 2012
Field2– Field3 ≦threshold? Field2– Field3 ≦threshold?
Field2 Field2
Active Video Active Video
Vsync1 Vsync1 Vsync2 Vsync2
Vsync1 – Vsync2 ≦threshold? Vsync1 – Vsync2 ≦threshold?
Vsync2 – Vsync3 ≦threshold? Vsync2 – Vsync3 ≦threshold?

Figure 92: STDI Vertical Locking Operation

Field2 Field2
Active Video Active Video
Vsync2 Vsync2

Figure 93: STDI VSync Monitoring Operation

Description
Readback value
Description
Readback value
Field3 – Field4 ≦threshold? Field3 – Field4 ≦threshold?
Field3 Field3
Active Video Active Video Active Video Active Video
Vsync3 Vsync3
Vsync3 – Vsync4 ≦threshold? Vsync3 – Vsync4 ≦threshold?
Latched Field Length Latched Field Length
Field3 Field3
Active Video Active Video Active Video Active Video
Vsync3 Vsync3
275
Field4 – Field5 ≦threshold? Field4 – Field5 ≦threshold?
Field4 Field4
Field5 Field5
Active Video Active Video
Vsync5 Vsync5
Vsync4 Vsync4
Vsync5 – Vsync4 ≦threshold? Vsync5 – Vsync4 ≦threshold?
F F
Field5 – F ≦threshold? Field5 – F ≦threshold?
Field4 Field4
Field5 Field5
Active Video Active Video
Vsync4 Vsync4
F F
Vsync5 – V ≦threshold? Vsync5 – V ≦threshold?
Latched Vsync Length Latched Vsync Length
ADV7850
Field6 Field6
Active Video Active Video
Field6 – F ≦threshold? Field6 – F ≦threshold?
Field6 Field6
Active Video Active Video
Vsync5 Vsync5