Datasheet

ADV7188
Rev. A | Page 19 of 112
Fast Blank and Contrast Reduction
Programmable Thresholds
The internal fast blank and contrast reduction signals are
resolved from the trilevel FB signal using two comparators, as
shown in
Figure 11. To facilitate compliance with different
input level standards, the reference level to these comparators is
programmable via FB_LEVEL [1:0] and CNTR_LEVEL [1:0].
The resulting thresholds are given in
Table 15 .
FB_LEVEL [1:0], Address 0xF1 [5:4]
These bits control the reference level for the fast blank comparator.
CNTR_LEVEL [1:0], Address 0xF1 [7:6]
These bits control the reference level for the contrast reduction
comparator.
–
+
PROGRAMMABLE
THRESHOLDS
–
+
CONTRAST
REDUCTION
COMPARATOR
C
FAST BLANK
COMPARATOR
FAST BLANK
FB PIN
CNTR_ENABLE
CNTR_LEVEL[1:0]
FB_LEVEL[1:0]
05478-011
Figure 11. Fast Blank and Contrast Reduction Programmable Threshold
Table 15. Fast Blank and Contrast Reduction Programmable Threshold I
2
C Controls
CNTR_ENABLE FB_LEVEL [1:0] CNTR_LEVEL [1:0] Fast Blanking Threshold (V) Contrast Reduction Threshold (V)
0 00 (default) XX 1.4 n/a
0 01 XX 1.6 n/a
0 10 XX 1.8 n/a
0 11 XX 2.0 n/a
1 00 (default) 00 1.6 0.4
1 01 01 1.8 0.6
1 10 10 2.0 0.8
1 11 11 2.2 2.0