AR# 6985: 4.2i Foundation Simulator - Schematic: Problems occur when a macro's hierarchy tap drives logic internal
4.2i Foundation Simulator - Schematic: Problems occur when a macro's hierarchy tap drives logic internal
Keywords: Foundation Schematic, Macro, Hierarchy connector, does not simulate
General Description: I have created a macro in Foundation Schematic. The macro contains a net that is connected to an output hierarchy connector; the net is also connected as an input to other internal logic.
When I select this net from the schematic and simulate, the simulator lists this net as an output, and the simulation for this signal is correct. However, the logic that this net drives is not correct, which results in an incorrect simulation.
This problem occurs because the simulator does not recognize that the signal is also an input to other logic within the macro; therefore, the input is never actually passed to this logic.
You can work around this problem in two ways:
1. Run the signal through a buffer before connecting it to the hierarchy connector. This prevents the simulator from recognizing this internal signal as an output only.
2. In Foundation Simulator, use the Signal -> Add Signals component selection window. Scroll through the hierarchy, and select the output of the logic that actually creates/drives the net.