AD9883/PCB AD [Analog Devices], AD9883/PCB Datasheet - Page 6

• Manufacturer Part Number: AD9883/PCB
• Description: 110 MSPS Analog Interface for Flat Panel Displays
• Manufacturer: AD [Analog Devices]

AD9883
PIN FUNCTION DETAIL
Outputs
HSOUT
VSOUT
SOGOUT
Serial Port
(Two-Wire)
SDA
SCL
A0
Data Outputs
RED
GREEN
BLUE
Data Clock
Output
DATACK
Horizontal Sync Output
A reconstructed and phase-aligned version of
the Hsync input. Both the polarity and dura-
tion of this output can be programmed via
serial bus registers.
By maintaining alignment with DATACK,
and Data, data timing with respect to horizon-
tal sync can always be determined.
Vertical Sync Output
A reconstructed and phase-aligned version of
the video Vsync. The polarity of this output
can be controlled via a serial bus bit. The place-
ment and duration in all modes is set by the
graphics transmitter.
Sync On Green Slicer Output
This pin outputs either the signal from the
Sync-On-Green slicer comparator or an unproc-
essed but delayed version of the Hsync input.
See the Sync Block Diagram (Figure 11) to
view how this pin is connected.
(Note: Besides slicing off SOG, the output from
this pin gets no other additional processing on
the AD9883. Vsync separation is performed via
the sync separator.)
Serial Port Data I/O
Serial Port Data Clock
Serial Port Address Input 1
For a full description of the two-wire serial
register and how it works, refer to the Two-
Wire Serial Control Port section.
Data Output, Red Channel
Data Output, Green Channel
Data Output, Blue Channel
The main data outputs. Bit 7 is the MSB. The
delay from pixel sampling time to output is
fixed. When the sampling time is changed by
adjusting the PHASE register, the output timing
is shifted as well. The DATACK and HSOUT
outputs are also moved, so the timing rela-
tionship among the signals is maintained. For
exact timing information, refer to Figures 7
and 8.
Data Output Clock
This is the main clock output signal used to
strobe the output data and HSOUT into
external logic.
It is produced by the internal clock generator
and is synchronous with the internal pixel
sampling clock.
Inputs
R
G
B
HSYNC
VSYNC
SOGIN
AIN
AIN
AIN
When the sampling time is changed by adjust-
ing the PHASE register, the output timing is
shifted as well. The Data, DATACK, and
HSOUT outputs are all moved, so the timing
relationship among the signals is maintained.
Analog Input for RED Channel
Analog Input for GREEN Channel
Analog Input for BLUE Channel
High-impedance inputs that accept the RED,
GREEN, and BLUE channel graphics signals,
respectively. (The three channels are identical,
and can be used for any colors, but colors are
assigned for convenient reference.)
They accommodate input signals ranging from
0.5 V to 1.0 V full scale. Signals should be
ac-coupled to these pins to support clamp
operation.
Horizontal Sync Input
This input receives a logic signal that estab-
lishes the horizontal timing reference and
provides the frequency reference for pixel
clock generation.
The logic sense of this pin is controlled by
serial register 0Eh Bit 6 (Hsync Polarity). Only
the leading edge of Hsync is active, the trailing
edge is ignored. When Hsync Polarity = 0, the
falling edge of Hsync is used. When Hsync
Polarity = 1, the rising edge is active.
The input includes a Schmitt trigger for noise
immunity, with a nominal input threshold
of 1.5 V.
Vertical Sync Input
This is the input for vertical sync.
Sync-on-Green Input
This input is provided to assist with processing
signals with embedded sync, typically on the
GREEN channel. The pin is connected to a
high-speed comparator with an internally gener-
ated threshold. The threshold level can be
programmed in 10 mV steps to any voltage
between 10 mV and 330 mV above the negative
peak of the input signal. The default voltage
threshold is 150 mV.
When connected to an ac-coupled graphics
signal with embedded sync, it will produce
a noninverting digital output on SOGOUT.
(This is usually a composite sync signal, contain-
ing both vertical and horizontal sync information
that must be separated before passing the hori-
zontal sync signal to Hsync.)
When not used, this input should be left uncon-
nected. For more details on this function and
how it should be configured, refer to the Sync
on Green section.