limit_vcd - 2023.2 English

Vivado Design Suite Tcl Command Reference Guide (UG835)

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2023.2 English

Limit the maximum size of the VCD file on disk (equivalent of $dumplimit verilog task)


limit_vcd [‑ports] [‑file <arg>] [‑quiet] [‑verbose] <filesize>


Name Description
[-ports] Control extended vcd dump file.
[-file] Specify the file where ports have to limit the file size in dumping . Default: Limits all dumpport files
[-quiet] Ignore command errors
[-verbose] Suspend message limits during command execution
<filesize> Specify the maximum size of the VCD file in bytes.



Specify the size limit, in bytes, of the Value Change Dump (VCD) file. This command operates like the Verilog $dumplimit simulator directive.

When the specified file size limit has been reached, the dump process stops, and a comment is inserted into the VCD file to indicate that the file size limit has been reached.

Note: You must run the open_vcd command before using the limit_vcd command.


-quiet - (Optional) Execute the command quietly, returning no messages from the command. The command also returns TCL_OK regardless of any errors encountered during execution.
Note: Any errors encountered on the command-line, while launching the command, will be returned. Only errors occurring inside the command will be trapped.
-verbose - (Optional) Temporarily override any message limits and return all messages from this command.
Note: Message limits can be defined with the set_msg_config command.

<filesize> - (Required) Specify the file size limit of the open VCD file in bytes.


The following example limits the current VCD file:

limit_vcd 1000