Using parameters to set port values
Some processor and peripheral component ports are almost always static in value when used as part of a typical platform. For example, the reset vector base address register address (RVBARADDR) port in processor components.
To facilitate easy configuration of platform models, the IP models for these components can provide a shadow parameter for these ports. This parameter can be used to change the value that is used by the model. In these cases, the following rules apply:
- If a port is driven in the platform model, then the parameter value is ignored.
- If a port is not driven in the platform model, then the parameter value is sampled at both simulator reset, and at every subsequent simulation reset of the specific IP model.
NoteSimulator reset corresponds with the LISA
reset()behavior and the SystemC
- All ports and parameters that are sampled at reset are sampled when the simulation reset signal concerned is deasserted.
- If a port is not driven in the platform model, and a parameter has not been set, then the default value for the parameter is used.
In some IP models, the value of some ports can only be set by using a parameter. That is, the parameter is provided instead of the port.