ViewSonic VG181 - Graphics Port

ViewSonic Service Manual
July 2000 - Version 1.0 VG181
THEORY OF CIRCUIT OPERATION
Graphics port
The graphics port (Gport) is an input interface for high speed RGB data (up to
SXGA). It accepts incoming data at one or two pixels per clock. It also has a sync
separator circuit, timing signals for PLL control, clock buffering and conditioning
circuitry. The graphics port has two input sources from an analog port and a digital
port. Analog and digital data cannot be processed simultaneously. This is
controlled through ADCOE and TMDSOE.
The block diagram of graphics port is shown below:
Data Register
and
Multiplexer
Memory
Interface
GREF
GFBK
GBLKSPL
GCOAST
GHSFOUT
PLL
Control
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