AD9925 Ver la hoja de datos (PDF) - Analog Devices
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AD9925 Datasheet PDF : 96 Pages
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AD9925
Table 11. HBLK Pattern Registers
Register Length Range
HBLKMASK 1 b
High/Low
H3HBLKOFF 1 b
High/Low
HBLKALT 2 b
0 to 3 Alternation Mode
HBLKTOG1 12 b
HBLKTOG2 12 b
HBLKTOG3 12 b
HBLKTOG4 12 b
HBLKTOG5 12 b
HBLKTOG6 12 b
0 to 4095 Pixel Location
0 to 4095 Pixel Location
0 to 4095 Pixel Location
0 to 4095 Pixel Location
0 to 4095 Pixel Location
0 to 4095 Pixel Location
Description
Masking Polarity for H1/H3 (0 = H1/H3 Low, 1 = H1/H3 High).
Addr 0xE7, Bit [6]. Set = 1 to keep H3/H4 active during HBLK pulse. Normal set to 0.
Enables Odd/Even Alternation of HBLK Toggle Positions.
0 = Disable Alternation.
1 = TOG1 to TOG2 Odd, TOG3 to TOG6 Even.
2 = 3 = TOG1to TOG2 Even, TOG3 to TOG6 Odd.
First Toggle Position within Line for Each Vertical Sequence 0 to 9.
Second Toggle Position within Line for Each Vertical Sequence 0 to 9.
Third Toggle Position within Line for Each Vertical Sequence 0 to 9.
Fourth Toggle Position within Line for Each Vertical Sequence 0 to 9.
Fifth Toggle Position within Line for Each Vertical Sequence 0 to 9.
Sixth Toggle Position within Line for Each Vertical Sequence 0 to 9.
Generating Special HBLK Patterns
There are six toggle positions available for HBLK. Normally,
only two of the toggle positions are used to generate the stan-
dard HBLK interval. However, the additional toggle positions
may be used to generate special HBLK patterns, as shown in
Figure 26. The pattern in this example uses all six toggle posi-
tions to generate two extra groups of pulses during the HBLK
interval. By changing the toggle positions, different patterns can
be created.
Generating HBLK Line Alternation
One further feature of the AD9925 is the ability to alternate dif-
ferent HBLK toggle positions on odd and even lines. This may be
used in conjunction with vertical pattern odd/even alternation or
on its own. When a 1 is written to the HBLKALT register, TOG1
and TOG2 are used on odd lines, while TOG3 to TOG6 are
used on even lines. Writing a 2 to the HBLKALT register gives
the opposite result: TOG1 and TOG2 are used on even lines,
while TOG3 to TOG6 are used on odd lines. See the Vertical
Timing Generation section for more information.
HD
HBLK
1
2
BLANK
PROGRAMMABLE SETTINGS:
1. FIRST TOGGLE POSITION = START OF BLANKING.
2. SECOND TOGGLE POSITION = END OF BLANKING.
Figure 24. Horizontal Blanking (HBLK) Pulse Placement
BLANK
HD
HBLK
H1/H3
H1/H3
H2/H4
NOTE
1. THE POLARITY OF H1 DURING BLANKING IS PROGRAMMABLE (H2 IS OPPOSITE POLARITY OF H1).
Figure 25. HBLK Masking Control
Rev. A | Page 20 of 96
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