DesignWorks optional digital simulator provides fully interactive, 13-state simulation. Schematic changes are reflected immediately in simulated results, both in flat and hierarchical designs. Signal values and device states can be probed right on the schematic. There is built-in support for RAMs, ROMs, PLDs and common logic types. A test vector module allows signal input and output values to be entered and viewed in text form, as an alternative to the waveforms displayed in the timing diagram.