AD9949
Rev. B | Page 21 of 36
HORIZONTAL CLAMPING AND BLANKING
The AD9949’s horizontal clamping and blanking pulses are fully
programmable to suit a variety of applications. Individual
sequences are defined for each signal, which are then organized
into multiple regions during image readout. This allows the
dark pixel clamping and blanking patterns to be changed at
each stage of the readout to accommodate different image
transfer timing and high speed line shifts.
INDIVIDUAL CLPOB AND PBLK SEQUENCES
The AFE horizontal timing consists of CLPOB and PBLK, as
shown in Figure 21. These two signals are independently
programmed using the parameters shown in Table 18. The start
polarity, first toggle position, and second toggle position are
fully programmable for each signal. The CLPOB and PBLK
signals are active low and should be programmed accordingly.
Up to four individual sequences can be created for each signal.
INDIVIDUAL HBLK SEQUENCES
The HBLK programmable timing shown in Figure 22 is similar
to CLPOB and PBLK. However, there is no start polarity
control.
Only the toggle positions are used to designate the
start and the stop positions of the blanking period. Additionally,
there is a polarity control, HBLKMASK, which designates the
polarity of the horizontal clock signals H1 to H4 during the
blanking period. Setting HBLKMASK high sets H1 = H3 = low
and H2 = H4 = high during the blanking,
as shown in Figure 23.
Up to four individual sequences are available for HBLK.
32
1
HD
CLPOB
PBLK
PROGRAMMABLE SETTINGS:
1. START POLARITY (CLAMP AND BLANK REGION ARE ACTIVE LOW).
2. FIRST TOGGLE POSITION.
3. SECOND TOGGLE POSITION.
ACTIVE
ACTIVE
03751-022
...
...
Figure 21. Clamp and Preblank Pulse Placement
21
HD
HBL
K
PROGRAMMABLE SETTINGS:
1. FIRST TOGGLE POSITION = START OF BLANKING.
2. SECOND TOGGLE POSITION = END OF BLANKING.
BLANK
BLANK
03751-023
...
...
Figure 22. Horizontal Blanking (HBLK) Pulse Placement
Table 18. CLPOB and PBLK Individual Sequence Parameters
Parameter Length Range Description
Polarity 1b High/Low Starting Polarity of Clamp and PBLK Pulses for Sequences 0 to 3.
Toggle Position 1 12b 0 to 4095 Pixel Location First Toggle Position within the Line for Sequences 0 to 3.
Toggle Position 2 12b 0 to 4095 Pixel Location Second Toggle Position within the Line for Sequences 0 to 3.
Table 19. HBLK Individual Sequence Parameters
Parameter Length Range Description
HBLKMASK 1b High/Low Masking Polarity for H1 for Sequences 0 to 3 (0 = H1 Low, 1 = H1 High).
Toggle Position 1 12b 0 to 4095 Pixel Location First Toggle Position within the Line for Sequences 0 to 3.
Toggle Position 2 12b 0 to 4095 Pixel Location Second Toggle Position within the Line for Sequences 0 to 3.
Toggle Position 3 12b 0 to 4095 Pixel Location Third Toggle Position within the Line for Sequences 0 to 3.
Toggle Position 4 12b 0 to 4095 Pixel Location Fourth Toggle Position within the Line for Sequences 0 to 3.
Toggle Position 5 12b 0 to 4095 Pixel Location Fifth Toggle Position within the Line for Sequences 0 to 3.
Toggle Position 6 12b 0 to 4095 Pixel Location Sixth Toggle Position within the Line for Sequences 0 to 3.
