Forcing signal and net values
The Edit > Force command displays a dialog box that allows you to apply stimulus to the selected signal or net. Multiple signals can be selected and forced; the force dialog box remains open until all of the signals are either forced, skipped, or you close the dialog box. To cancel a force command, use the Edit > NoForce command. See also the force command.
The Force dialog box includes these options:
- Signal Name
Specifies the signal or net for the applied stimulus.
- Value
Initially displays the current value, which can be changed by entering a new value into the field. A value can be specified in radixes other than decimal by using the form (for VHDL and Verilog, respectively):
base#value -or- b|o|d|h'value
16#EE or h'EE, for example, specifies the hexadecimal value EE.
- Kind: Freeze
Freezes the signal or net at the specified value until it is forced again or until it is unforced with a noforce command.
Freeze is the default for Verilog nets and unresolved VHDL signals and Drive is the default for resolved signals.
If you prefer Freeze as the default for resolved and unresolved signals, you can change the default force kind in the modelsim.ini file; see "Projects and system initialization" .
- Kind: Drive
Attaches a driver to the signal and drives the specified value until the signal or net is forced again or until it is unforced with a noforce command. This value is illegal for unresolved VHDL signals.
- Kind: Deposit
Sets the signal or net to the specified value. The value remains until there is a subsequent driver transaction, or until the signal or net is forced again, or until it is unforced with a noforce command.
- Delay For
Allows you to specify how many time units from the current time the stimulus is to be applied.
- Cancel After
Cancels the force command after the specified period of simulation time.
- OK
When you click the OK button, a force command is issued with the parameters you have set, and is echoed in the Main window. If more than one signal is selected to force, the next signal down appears in the dialog box each time the OK button is selected. Unique force parameters can be set for each signal.
