pyDigitalWaveTools

Python library for operations with VCD and other digital wave files. The VCD spec is a part of verilog standard e.g. IEEE.1364-2005, IEEE.1800-2017

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 python3importjsonimportsysfrompyDigitalWaveTools.vcd.parserimportVcdParseriflen(sys.argv) >1:
fname=sys.argv[1]
else:
print('Give me a vcd file to parse')
sys.exit(-1)
withopen(fname) asvcd_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