AD9927 Analog Devices, AD9927 Datasheet - Page 22

• Manufacturer Part Number: AD9927
• Description: 14-Bit CCD Signal Processor
• Manufacturer: Analog Devices

AD9927
Individual HBLK Patterns
The HBLK programmable timing shown in Figure 25 is similar
to CLPOB and PBLK; however, there is no start polarity control.
Only the toggle positions are used to designate the start and
stop positions of the blanking period. Additionally, there are
separate masking polarity controls for H1, H2, and HL that
designate the polarity of the horizontal clock signals during the
blanking period. Setting HBLKMASK_H1 high sets H1, and
therefore H3, H5, and H7, low during the blanking, as shown in
Figure 26. As with the CLPOB and PBLK signals, HBLK
registers are available in each V-sequence, allowing different
blanking signals to be used with different vertical timing
sequences.
The AD9927 supports three modes of HBLK operation. HBLK
Mode 0 supports basic operation and some support for special
HBLK patterns. HBLK Mode 1 supports pixel mixing HBLK
H1/H3/H5/H7
HBLK
H1/H3/H5/H7
H2/H4/H6/H8
HBLK
HD
HD
H1/H3
H2/H4
HBLK
HBLKTOGE1
SPECIAL H-BLANK PATTERN IS CREATED USING MULTIPLE HBLK TOGGLE POSITIONS (HBLKALT = 0)
BASIC HBLK PULSE IS GENERATED USING HBLKTOGE1 AND HBLKTOGE2 REGISTERS (HBLKALT = 0)
HBLKTOGE1
BLANK
HBLKTOGE2
Figure 25. Typical Horizontal Blanking Pulse Placement (HBLKMODE = 0)
Figure 27. Using Multiple Toggle Positions for HBLK (HBLKMODE = 0)
THE POLARITY OF H1/H3/H5/H7 DURING BLANKING IS PROGRAMMABLE
(H2/H4/H6/H8 AND HL ARE SEPARATELY PROGRAMMABLE)
HBLKTOGE2
Figure 26. HBLK Masking Polarity Control
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HBLKTOGE3
HBLKTOGE4
operation. HBLK Mode 2 supports advanced HBLK operation.
The following sections describe each mode in detail. Register
parameters are described in detail in Table 11.
HBLK Mode 0 Operation
There are six toggle positions available for HBLK. Normally,
only two of the toggle positions are used to generate the
standard HBLK interval. However, the additional toggle
positions can be used to generate special HBLK patterns, as
shown in Figure 27. The pattern in this example uses all six
toggle positions to generate two extra groups of pulses during
the HBLK interval. By changing the toggle positions, different
patterns can be created.
Separate toggle positions are available for even and odd lines. If
alternation is not needed, the same values should be loaded into
the registers for even (HBLKTOGE) and odd (HBLKTOGO) lines.
HBLKTOGE5
HBLKTOGE6
BLANK