Pre Release Rev.1.04 Page 20 of 211
Nov. 19, 2018
RAA278842, 43 3. Functional Description
CONFIDENTIAL
3. Functional Description
3.1 Overview
The RAA278842 and RAA278842 are highly integrated LCD video processors that incorporate many of the
features required to create a cost effective multipurpose LCD display system. This includes a high quality 2D
comb NTSC/PAL/SECAM video decoder that supports single-ended or differential composite video inputs, two
TTL digital input interfaces, two LVDS Open LDI input interfaces, a MIPI-CSI2 input interface, as well as an
EEPROM/SPI interface. The outputs include a dual channel LVDS Open LDI panel interface and a separate MIPI-
CSI2 output in RAA278842 or a pseudo BT.656 output in the RAA278843. Both devices can support input
resolutions up to 1080p and can drive LCD panels up to 1920x1080. The video processing capabilities include
arbitrary H/V scaling using a high quality scaler and de-interlacer engine, panoramic scaling, image mirroring,
image adjustment and enhancement utilizing 10-bit per color processing, black and white stretch, a versatile OSD
and much more. In addition, the RAA278842 and RAA278843 have a multi-feature image integrity diagnostic
capability to dynamically determine if the input video is corrupted. The feature set and versatility of this device
makes it an ideal solution for automotive LCD display applications.
The integrated analog front-end contains an ADC with clamping circuits, Automatic Gain Control (AGC) circuits,
and anti-aliasing filters to minimize the external component count. The built-in video decoder employs proprietary
2D comb filter Y/C separation technologies to produce exceptionally high quality video.
The chip's internal logic synchronizes the panel frame rate to the incoming video frame rate. A high quality
image-scaling engine is used to convert the different input resolution formats to the output panel resolution. An
internal de-interlacing engine also allows interlaced video to be displayed.
In addition, RAA278842 and RAA278843 have an array of integrated value-added features providing input/output
flexibility that make these devices extremely versatile single chip solutions. On Screen Display (OSD) is supported
through a built-in multi-window OSD engine offering text and graphical overlays. These products have integrated
diagnostic functions such as Short Diagnostics (Short-to-Battery (STB) and Short-to-Ground (STG) detection), as
well as two independent input measurement engines that can determine if the incoming video is corrupt. A separate
MIPI-CSI2 (RAA278842) or pseudo BT.656 (RAA278843) output port can route video to an application processor
independent of what is being processed through the LCD display output path. The host control interface supports a
standard two-wire serial bus.
3.2 Input Mux
The RAA278842 and RAA278843 have 6 different input video channels which can each be routed to 4 different
destinations. To accomplish all combinations a register controlled 6 to 4 mux is utilized. Because of input pin
sharing some combinations may not be possible. A typical case would mux 2 video inputs to independent output
paths as well as a measurement unit.
3.3 Analog Front-End
The analog front-end converts analog video signals to the required digital format. Each channel contains an
automatic clamping circuit, AGC circuit, anti-aliasing filter, and high performance ADCs to minimize the number
of external components needed in a system. The clamping circuit restores the signal DC level so it can be
accurately digitized. Multiple analog inputs that can be configured as single ended or differential are available and
switchable through software control. For register details of the Analog Front-End see the Register Description:
“5.15
Decoder” on page 110.
3.4 Video Decoder
The details of the registers that configure the Video Decoder are in the Register Description: “5.15 Decoder” on
page 110.
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