How do I use bidirectional ports with a System Generator for DSP design?
There is currently no way to enable bi-directional ports from System Generator gateway blocks. HDL Black Boxes can now support bi-directional I/O at the top level, but these signals will not be routed into the Simulink model. They will only be routed to the top level of the System Generator design when generated.
Alternatively, the System Generator design contains a "gateway in" and a "gateway out", which will be synthesized into ports. You may create a wrapper VHDL file to instantiate the design and map a bidirectional pin (with control logic on the output) to the two gateways.