Video Input/Output Daughter Card
41
UG235 (v1.2.1) October 31, 2007
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Chapter 5
DVI/VGA Output Interface
Overview
The VIODC supports both digital and analog outputs over the DVI output connector. The
interface supports standards up to UXGA (165 MHz pixel clock). By connecting a VGA to
the DVI adapter to the DVI output connector, VGA output is also supported.
shows a block diagram of the DVI and VGA output subsystem. A Texas
Instruments TFP410 IC is used to generate the digital DVI interface. An Analog Devices
ADV7123 triple DAC is used to generate the analog VGA compatible video signals. Both
devices are connected to a common 30-bit digital video bus carrying RGB data, HSYNC
and VSYNC. Independent pixel clocks are routed the devices. The triple DAC supports 10-
bit/channel RGB video. DVI interface supports only 8-bit/channel video, and the video
data ports are connected to the 8 MSBs of the video data bus. The DVI interface also
requires a data enable to distinguish active video from inactive video pixels.
The TPF410 is configured via as I2C bus interface. The DAC requires no configuration.
An I2C bus called DVI_OUT_DDC_SDA,SCL is routed from the XCV2P7 FPGA to support
an I2C EPROM on the DVI output interface.
Figure 5-1:
DVI/VGA Video Output Interface Block Diagram
XCV2P7
FPGA
TFP410
DVI Input
DVI Output
Connector
Serial DVI
Digital Video
Signals
VGA Compatible
Analog RGB Video
+
hsync, vsync
ADV7123
Triple
DAC VGA
Output
10-bit RGB Digital
Video, Pixel Clock
ug235_ch5_01_121905
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