Apalis Carrier Board Design Guide - Toradex

Apalis Carrier Board Design GuideThe HDMI and DVI interfaces define different connectors. There are passive adapters available inboth directions. Please be aware that HDMI and HDCP have licensing restrictions in place.2.8.1 HDMI/DVI SignalsApalisPinApalisSignal NameI/OTypePowerRailDescription240 HDMI1_TXC+ O TDMS HDMI/DVI differential clock positive242 HDMI1_TXC- O TDMS HDMI/DVI differential clock negative234 HDMI1_TXD0+ O TDMS HDMI/DVI differential data lane 0 positive236 HDMI1_TXD0- O TDMS HDMI/DVI differential data lane 0 negative228 HDMI1_TXD1+ O TDMS HDMI/DVI differential data lane 1 positive230 HDMI1_TXD1- O TDMS HDMI/DVI differential data lane 1 negative222 HDMI1_TXD2+ O TDMS HDMI/DVI differential data lane 2 positive224 HDMI1_TXD2- O TDMS HDMI/DVI differential data lane 2 negative220 HDMI1_CEC I/O OD 3.3V HDMI consumer electronic control232 HDMI1_HPD I CMOS 3.3V Hot-plug detect205 I2C2_SDA I/O OD 3.3V I 2 C interface for reading the extended display identification data (EDID)207 I2C2_SCL O OD 3.3V over DDC. This interface is shared with other display interfaces2.8.2 Reference Schematics2.8.2.1 DVI Schematic ExampleTable 17: HDMI/DVI signalsThere are different DVI connector configurations available. The DVI-D (digital) supports only thenative DVI signals. The DVI-A (analogue) provides only analogue VGA signals. The DVI-I(integrated) combines the digital DVI signals and the analogue VGA signals. For the DVI-A andDVI-I, there are passive adapters to the D-SUB VGA connector available. There is only one DDCchannel available on the DVI-I interface. Therefore, the connector is not designed to use both links(DVI and VGA) simultaneously. Nevertheless, there are Y-cables available which provide a DVI andVGA output. Such cables are not standardized normally. They provide the DDC on either the DVIor VGA output. Please be aware of this when using a similar Y-cable.The following schematic example shows a DVI-I implementation. It can be used as an example fora DVI-D design if you simply remove the analogue VGA signals. The sync signals for the VGAsignals need to be level shifted from 3.3V to 5V. The same is necessary for the DDC signals. TheTDMS signals need to be ESD protected using diodes. The schematic example shows a discretesolution for the level shifting and protection. There are integrated solutions also available.Toradex AG l Altsagenstrasse 5 l 6048 Horw l Switzerland l +41 41 500 48 00 l www.toradex.com l info@toradex.com Page | 42