From the point of view of the simulator, the DSM is a large single component in the simulation. The model is sensitive to all of its inputs and can, as far as the simulator is aware, drive output values as a response to any one of them changing. It is treated by the simulator as a large combinatorial block. The model and simulator provide no special treatment to clock signals. They are considered as input signals, like any other, that can cause output events to be generated.

The DSM does not include any information about the timing behavior of the core but it does provide a timing wrapper for you to backannotate your own timing information onto. You can backannotate timing information onto a DSM from an SDF file, as described in IEEE 1497-2001, using the annotation facilities provided by the simulator that you are using.

You can have difficulty in successfully integrating DSMs into a timing flow because they are large single components, and there are consequential implications for the level of timing accuracy that you can achieve. This chapter describes the way that DSM timing works, some limitations of the DSM timing model, and some suggestions on how to make a DSM best fit with your timing flow.

The timing shell is described further in: