Support the 4 extra HDMI outputs when a VMOD-MIB is connected to the Atlys

[mithro]

http://www.digilentinc.com/Products/Detail.cfm?Prod=VMOD-MIB

The Digilent Vmod Module Interface Board (VmodMIB) is a simple solution for interfacing additional peripheral modules and HDMI devices to VHDCI-equipped Digilent system boards. It connects to the VHDCI connector on Digilent system boards and provides four additional Pmod and four additional HDMI connections.

[mithro]

We should get the VmodMIB working. I believe @enjoy-digital fried his Atlys board however.

You can't use all the extra VmodMIB connectors for extra HDMI inputs. The Spartan 6 only has 4 x Phase Lock Loops (PLL) and you need one 1 x PLL per HDMI input. You also need 1 x PLL for driving the memory and CPU. This means there is at most 1 x PLL free for usage with the VmodMIB which means only 1 more input is possible. It should be possible to use the remaining 3 connectors as outputs.

Couple of things which need to be checked;

• TMDS_33 signals need a 3V3 VCCIO on the bank. This means the VHDCI expansion connector needs to be set to the 3V3 level.
• TMDS_33 signals can only be placed on certain banks. Check that this is compatible with the banks used on the VHDCI expansion connector.