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*E,OBJACC: Object must have write access: <object name>

prkroon

I am new to the forum so I do not know if the subject I post in this forum is the correct place.

Anyway, During simulation in ncsim I want to force an internal digital signal in the mixed signal design to a certain binairy value.

The signal in question is generated in vhdl and in my opinion a normal digital signal output.

However when I force it during simulation I get the following message:

*E,OBJACC: Object must have write access: <object name>

The <object name> is the signal/pin I force.

I searched in the online ncsim/simvision manuals and cadence site but sofar I could not find the cause of the error message.

So the question is why I can't force this digital signal, other signals in the design I can but some I can not giving me the discussed error message.

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  • TAM1

    The NC simulator does a lot of optimizations when it builds its data structures. In the interest of speed, it sets things up without providing for the capability of forcing a value on an internal signal from the TCL command line. In fact, for all we know, the presence of that signal may have been optimized completely away by the elaborator.

    If you want the simulator to set things up so that you can write a value into a signal, you need to provide "write" access to that signal. You can do it on the command line by adding the option "-access w". This may slow the simulation down by a small percentage, but if you are running interactively and forcing signals, that is usually not a problem.

     PS. There are 3 types of access that NC allows the user to control. "read" access allows TCL commands or database probes access to the values on internal signals. "write" access adds more information allowing TCL to put a new value on a signal. "connectivity" access keeps information about how a signal is connected in the design, for use by the schematic viewer for example. You can enable all 3 types of access with the option "-access rwc".

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  • TAM1

    The NC simulator does a lot of optimizations when it builds its data structures. In the interest of speed, it sets things up without providing for the capability of forcing a value on an internal signal from the TCL command line. In fact, for all we know, the presence of that signal may have been optimized completely away by the elaborator.

    If you want the simulator to set things up so that you can write a value into a signal, you need to provide "write" access to that signal. You can do it on the command line by adding the option "-access w". This may slow the simulation down by a small percentage, but if you are running interactively and forcing signals, that is usually not a problem.

     PS. There are 3 types of access that NC allows the user to control. "read" access allows TCL commands or database probes access to the values on internal signals. "write" access adds more information allowing TCL to put a new value on a signal. "connectivity" access keeps information about how a signal is connected in the design, for use by the schematic viewer for example. You can enable all 3 types of access with the option "-access rwc".

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