CX25870/871
3.0 PC Board Considerations
Flicker-Free Video Encoder with Ultrascale Technology
3.7 CX870EVK Evaluation Kit
3.7 CX870EVK Evaluation Kit
A new reference design kit is available now to facilitate implementation of
Conexant’s VGA encoder into a graphics subsystem. This kit is called the
GeForce2 MX-400 CX870EVK and can be obtained through your local Conexant
Systems sales office.
The new CX25870 Evaluation Kit uses the NVidia P36 model reference
design AGP card, containing the popular NVidia GeForce2 MX-400™
graphics-processing unit (GPU), as a high-performance data master to provide
digital data to the CX25870 PC video encoder. The Conexant device has been
mounted directly on this graphics card along with all necessary passive
components (resistors, capacitors, inductors, video connectors, etc.) to ensure
proper device operation. This two-chip combination is controlled by a set of
drivers for the graphics accelerator written by NVidia and a separate Windows
program called Super Cockpit created by Conexant that allows direct
manipulation of the encoder device by circumventing the driver software. All the
necessary documents and cables have been within the kit as well. The
multipronged DV-H cable from JIC USA is included with the kit and will be
necessary for viewing of HDTV, 480i Component Video Out, S-Video,
Composite, and any other TV output from the CX25870 encoder.
To obtain the necessary CX870EVK software, find a PC with Internet access
and visit the CX25870 https://site. For the site address, username, and password,
contact your local Conexant Systems sales office. Once you have been given user
identification information, you can download the GeForce2 MX-400 CX870EVK
instruction manual, Super Cockpit, test images, and other pertinent software.
The CX870EVK was designed to be both a demonstration unit and
development unit depending on a customer’s needs. For demonstration purposes,
many script files have been created and will be automatically extracted and
placed into a /ScriptFiles subdirectory under the CX870EVK’s main directory. To
execute a script file, launch a DOS-BOX, type the desired script filename
(without the extension) on the command line, and then press the <ENTER> key.
After execution, the script file will have configured both the CX25870 encoder
and the GeForce2 MX-400 graphics controller to a specific mode in terms of
resolution and video output. This is the most effective method for achieving the
optimal TV Out picture quickly.
For development purposes, several new pages have been added to Super
Cockput including the handy Clipboard pages which allow the end-user to try out
register values and restore them if the result is not desirable. All registers can be
read from as well—an improvement over the Bt868/9. Write access to all the new
bits and registers found within the CX25870 are also possible. Note that the
GeForce2 MX-400 controller supports the CX25870 in a pseudo-master
interface. As a result, HDTV YPRPB Output is possible with the GeForce2
MX-400 CX870EVK kit.
100381B
Conexant
3-31
CONEXANT [ CONEXANT SYSTEMS, INC ]
