DRIVE TWO DISPLAYS WITH ONE HDMI INTERFACE

John, one solution is to use the TMDS442, as described in this post: http://e2e.ti.com/support/interface/high_speed_interface/f/138/t/151528.aspx#549979

Another solution is to use 2 TFP410 devices, with most of their CMOS inputs tied together (along with small series resistors to reduce reflections).

Best regards,
RE

Hi Ross,

The customer is planning to connect a repeater to his existing HDMI interface to create two HDMI interfaces.  I don't think this will work, but having difficulty describing the reason for it.  I explained that the HDMI interface is bi-directional so communications between the monitor connected to the original HDMI interface will conflict with the repeated connected to it as well.  Is this the case?

Regards,

John 

The TMDS lanes are 1-directional.  Other HDMI lines can be bidirectional.  A TMDS receiver has internal termination, so you don't want to connect multiple receivers to the same TMDS lane.

Best regards,
RE

The customer is considering a MAX3815 instead.  I think that your suggestion of TFP410 should work over the MAX3815.  Can you call me to discuss this?

The customer also was considering National part number DS16EV5110A.   Could this work? 

Regards,

John

After looking into the TFP410 I see that it is serializing a parallel bus so I don’t understand how this would work.

Regards,

John

Hi John,

The TFP410 converts 24-bit RGB data into TMDS that complies with HDMI/DVI.  You said the TFP410 is currently being used.  I recommended the option of redesigning that PCB to use 2 TFP410 devices, where their 28-bit parallel input interface is shared.  It isn't difficult to tie CMOS lines to multiple high impedance CMOS receivers.

You could instead use a 1:2 fanout buffer on the TMDS, and the TMDS442 is suitable for that function.  You don't want to use a repeater like the DS16EV5110A, since it only has 1 TMDS output channel.

Best regards,
RE