AD9927 Analog Devices, AD9927 Datasheet - Page 15

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

SYSTEM OVERVIEW
Figure 13 shows the typical system block diagram for the AD9927
in master mode. The CCD output is processed by the AD9927’s
AFE circuitry, which consists of a CDS, VGA, black level clamp,
and ADC. The digitized pixel information is sent to the digital
image processor chip, which performs the postprocessing and
compression. To operate the CCD, all CCD timing parameters
are programmed into the AD9927 from the system microprocessor
through the 3-wire serial interface. From the master clock, CLI,
provided by the image processor or external crystal, the AD9927
generates the CCD’s horizontal and vertical clocks and internal
AFE clocks. External synchronization is provided by a sync
pulse from the microprocessor, which resets the internal
counters and resyncs the VD and HD outputs.
CCD
GPO1 TO GPO8
CLI
HD
V1A TO V15, SUBCK
VD
Figure 13. Typical System Block Diagram, Master Mode
H1 TO H8, HL,
RG, VSUB
CCDIN
SYNC
MAX VD LENGTH IS 8192 LINES
AD9927
V-DRIVER
AFETG
SERIAL
INTERFACE
HD, VD
DOUT
DCLK
CLI
MAX HD LENGTH IS 8192 PIXELS
µP
PROCESSING
DIGITAL
IMAGE
ASIC
Figure 15. Maximum VD/HD Dimensions
Rev. 0 | Page 15 of 100
Alternatively, the AD9927 can be operated in slave mode. In
this mode, the VD and HD are provided externally from the
image processor, and all AD9927 timing is synchronized with
VD and HD.
The H-drivers for H1 to H8, HL, and RG are included in the
AD9927, allowing these clocks to be directly connected to the
CCD. An H-driver voltage of up to 3.3 V is supported. V1A to
V15 and SUBCK vertical clocks are included as well, allowing
the AD9927 to provide all horizontal and vertical clocks
necessary to clock data out of a CCD.
The AD9927 includes programmable general-purpose outputs
(GPO), which can trigger mechanical shutter and strobe (flash)
circuitry.
Figure 14 and Figure 15 show the maximum horizontal and vertical
counter dimensions for the AD9927. All internal horizontal and
vertical clocking is controlled by these counters, which specify
line and pixel locations. Maximum HD length is 8192 pixels per
line, and maximum VD length is 8192 lines per field.
MAXIMUM COUNTER DIMENSIONS
13-BIT HORIZONTAL = 8192 PIXELS MAX
Figure 14. Vertical and Horizontal Counters
13-BIT VERTICAL = 8192 LINES MAX
AD9927