jez2vcd: JEZ-to-VCD Waveform Format Converter

Overview

The jez2vcd utility converts a waveform file in JEZ format to a waveform file in VCD (Value Change Dump) format so that the XMODEL simulation results can be viewed using other waveform viewers if necessary.

However, it is advised that the conversion is not without costs. For instance, some accuracy can be lost since the analog, continuous-time waveforms will be converted into piecewise-linear approximations. Also, the resulting VCD-format waveform file may have a significantly larger size than the original JEZ-format file, which may take a long time to load.

Basic Command

The simplest way to convert a JEZ-format waveform file to a VCD-format file is to execute a command jez2vcd with the input waveform filename as the argument.

unix> jez2vcd <filename.jez>

Then, the utility generates a new file which has the same name with the input file but the .vcd extension. For instance:

unix> jez2vcd xmodel.jez

converts the input file xmodel.jez to an output file xmodel.vcd.

To set a different output filename, the -o option can be used. For instance:

unix> jez2vcd xmodel.jez -o mywave.vcd

The next subsection describes a full list of available options.

Available Options

Typing the command jez2vcd -h on the UNIX command-line prompt displays all the available options for the jez2vcd utility.

unix> jez2vcd -h
Usage: jez2vcd.pyo [options] <filename>

Converts a JEZ-formatted file into a VCD-formatted file.

Options:
  -h, --help             show this help message and exit
  -o FILENAME, --output=FILENAME
                         name the output VCD-format file.
  -l, --list             list variables and their types.
  -v VARNAME1,VARNAME2,..., --vars=VARNAME1,VARNAME2,...
                         convert selected variables only; use a comma-separated list.
  -b, --xbit, --bit      convert only xbit/bit typed variables.
  -r, --xreal, --real    convert only xreal/real/meas typed variables.
  -i, --integer          force integer-valued time points. The timescale Is forced 
                         equal to the sampling time period (default: 1e-12)
  -f, --fixed            sample xreal waveforms in fixed timesteps.
  -t T_SAMPLE, --tsample=T_SAMPLE
                         the sampling period for xreal waveforms: default is 1ps.
  --abstol=ABSTOL        absolute tolerance for sampling xreal waveforms:
                         default is 1e-4.
  --reltol=RELTOL        relative tolerance for sampling xreal waveforms:
                         default is 1e-4.

Descriptions on the selected options are as follow:

Signal selection options:

• -b, --xbit, or --bit: converts only digital-type signals.
• -r, --xreal, or --real: converts only analog-type signals.
• -v VARNAME1,VARNAME2,… or --vars=VARNAME1,VARNAME2,…: converts only the signals listed in a comma-separated list of variable names.

Conversion control options:

• -t T_SAMPLE or --tsample=T_SAMPLE: specifies the minimum sampling period for approximating the xreal-typed waveforms.
• --abstol=ABSTOL: defines the absolute tolerance when sampling the xreal-typed waveforms.
• --reltol=RELTOL: defines the relative tolerance when sampling the xreal-typed waveforms.
• -f or --fixed: sample xreal-typed waveforms in fixed timesteps instead of variable timesteps.
• -i or --integer: force integer-valued time values. In this mode, the timescale is forced equal to the sampling time period.

Miscellaneous options:

• -h: displays the help messages.
• -l or --list: displays the list of variables contained in the input file.
• -o or --output: defines the output waveform filename.