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AD9920A
Rev. B | Page 37 of 112
XV1
XV8
HD
XV9
XV10
XV1 TO XV8 USE
V-PATTERN GROUP A
XV9, XV10 USE
V-PATTERN GROUP B
06
87
8-
04
3
Figure 44. Using Separate Group A and Group B Patterns
XV1
XV24
HD
V-PATTERN GROUP A
V-PATTERN GROUP B
V-PATTERN GROUP C
V-PATTERN GROUP D
06
87
8-
0
44
Figure 45. Combining Multiple V-Patterns Using CONCAT_GRP = 1
XV1
XV10
HD
V-PATTERN GROUP A
V-PATTERN GROUP B
GROUP A REP 1
GROUP A REP 2
GROUP A REP 3
06
87
8-
0
45
Figure 46. Combining Group A and Group B Patterns with Repetition
Group A/Group B/Group C/Group D Selection
If additional flexibility is needed, some outputs can be set to
Group B, Group C, or Group D in the GROUPSEL registers. In
this case, those selected outputs use the V-pattern group specified
by the VPATSELB, VPATSELC, or VPATSELD registers.
Figure 44shows an example where the V9 and V10 outputs use a separate
V-pattern Group B to perform special CCD timing.
The AD9920A has the flexibility to use four different V-pattern
groups in a vertical sequence. In general, the vertical outputs
use the same V-pattern group during a particular sequence. It
is possible to assign some of the outputs to a different V-pattern
group, which can be useful in certain CCD readout modes.
Another application of the Group A, Group B, Group C, and
Group D registers is to combine up to four different V-pattern
groups together for more complex patterns. This is accom-
plished by setting the CONCAT_GRP register (Address 0x00,
Bits[13:10]) equal to 0x01. This setting combines the toggle
positions from the V-pattern groups specified by registers
VPATSELA, VPATSELB, VPATSELC, and VPATSELD for a
maximum of up to 16 toggle positions. Example timing for the
The GROUPSEL registers are used to select the group (A, B, C,
or D) for each V-output. In general, only a single V-pattern
group is needed for the vertical outputs; therefore, Group A
should be selected for all outputs by default (GROUPSEL_0,
GROUPSEL_1 = 0x00). In this configuration, all outputs use
the V-pattern group specified by the VPATSELA register.