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GS4911B/GS4910B Data Sheet
36655 - 2
April 2006
47 of 113
3.5.3 Behaviour on Loss and Re-acquisition of the Reference Signal
By default, the GS4911B/GS4910B will ignore one missing H pulse on the HSYNC
pin and will continue to operate in Genlock mode (although the LOCK_LOST pin
will temporarily be set HIGH). This behaviour is controlled by the Run_Window bits
of register address 24h.
If there are two consecutive missing H pulses on the HSYNC input pin, the
REF_LOST and LOCK_LOST pins will both go HIGH and the device will enter
Freeze mode. An internal flywheel ensures the selected output clock and timing
signals maintain their previous phase and frequency and continue to operate
without glitches.
The VSYNC and FSYNC signals are not monitored in Genlock mode; loss of signal
on these pins will not affect the operation of the device.
NOTE 1: If the input reference is removed and re-applied, all line-based timing
outputs will be inaccurate for up to one frame for all output standards.
Table 3-2: Ambiguous Standard Identification
Number
Standard
H
(27MHz
Clocks)
16_H
(27MHz
Clocks)
V (lines)
F (lines)
Amb_Std_Sel[10:0]
1
1920x1080/60/2:1 interlace
800
12800
562.5
1125
X X X X X X X X X 0 0
1920x1080/30/PsF
800
12800
562.5
1125
X X X X X X X X X 0 1
1920x1035/60/2:1 interlace
800
12800
562.5
1125
X X X X X X X X X 1 0
2
1920x1080/59.94/2:1 interlace
800.8
12813
562.5
1125
X X X X X X X 0 0 X X
1920x1080/29.97/PsF
800.8
12813
562.5
1125
X X X X X X X 0 1 X X
1920x1035/59.94/2:1 interlace
800.8
12813
562.5
1125
X X X X X X X 1 0 X X
3
1920x1080/50/2:1 interlace
960
15360
562.4
1125
X X X X X 0 0 X X X X
1920x1080/25/PsF
960
15360
562.4
1125
X X X X X 0 1 X X X X
4
601 525 / 2:1 interlace
1716
27456
262.5
525
X X X 0 0 X X X X X X
720x486/59.94/2:1 interlace
1716
27456
262.5
525
X X X 0 1 X X X X X X
4fsc 525 / 2:1 interlace
1716
27456
262.5
525
X X X 1 0 X X X X X X
601 - 18MHz 525/2:1 interlace
1716
27456
262.5
525
X X X 1 1 X X X X X X
5
601 625 / 2:1 interlace
1728
27648
312.5
625
X 0 0 X X X X X X X X
720x576/50/2:1 interlace
1728
27648
312.5
625
X 0 1 X X X X X X X X
Composite PAL 625/2:1/25
1728
27648
312.5
625
X 1 0 X X X X X X X X
601 - 18MHz 625/2:1 interlace
1728
27648
312.5
625
X 1 1 X X X X X X X X
6
640 x 480 VGA @ 60Hz
857.14
13714
525
525
0 X X X X X X X X X X
720x483/59.94/1:1 progressive
858
13728
525
525
1 X X X X X X X X X X
NOTE: ‘X’ signifies ‘don’t care.’ The X bit will be ignored when determining which standard to select in each of the 6 groups above.