pyDigitalWaveTools

python library for operations with VCD and other digital wave files

Feature list

• parse VCD (std 2009) files to intermediate format
• write VCD files, user specified formatters for user types, predefined formatters for vectors, bits and enum values
• dump intermediate format as simple json

Hello pyDigitalWaveTools

Here is a simple example how to use the VCD parser:

#!/usr/bin/env python3
import json
import sys
from pyDigitalWaveTools.vcd.parser import VcdParser

if len(sys.argv) > 1:
    fname = sys.argv[1]
else:
    print('Give me a vcd file to parse')
    sys.exit(-1)

with open(fname) as vcd_file:
    vcd = VcdParser()
    vcd.parse(vcd_file)
    data = vcd.scope.toJson()
    print(json.dumps(data, indent=4, sort_keys=True))

Output json format

scope
{ "name": "<scope name>"
  "children" : {"<children name>" : child}
}

child can be scope or signal record

signal record
{ "name": "<signal name>"
  "type": {"sigType": "<vcd signal type>",
           "width": <bit width of signal (integer)>},
  "data": [<data records>],
}

data record format
[<time (number)>, <value (string, format dependent on datatype)>]

Related open source

• verilog-vcd-parser - Python, A parser for Value Change Dump (VCD) files as specified in the IEEE System Verilog 1800-2012 standard.
• pyvcd - Python, vcd writer, GTKWave config writer
• vcdvcd - Python, vcd parser, dump pretty printer