vcd-parser

A Node.js parsing tool for Value Change Dump (VCD) files and generating a readable JSON document. It can be used with different hardware simulation tools such as Icarus Iverilog.

Installation

npm install --save vcd-parser

Usage example

const VCDParser = require('vcd-parser');
VCDParser.parse(
    `
    $date
    Tue Feb 12 14:01:15 2019
    $end
    $version
    Icarus Verilog
    $end
    $timescale
    1ns
    $end
    $scope module test_tb $end
    $var reg 1 ! clk $end
    $var wire 1 " rst $end
    $upscope $end
    $enddefinitions $end
    #0
    $dumpvars
    0"
    0!
    $end
    #15
    1"
    #20
    1!
    #40
    0!
    #60
    1!
    #80
    0!
    #100
    1!
    #115
`
)
    .then(parsedData => {
        console.log(parsedData);
        // {
        // 	"date": "Tue Feb 12 14:01:15 2019",
        // 	"version": "Icarus Verilog",
        // 	"timescale": "1ns",
        // 	"endtime": "115",
        // 	"scale": "1ns",
        // 	"signal": [
        // 		{
        // 			"type": "reg",
        // 			"size": 1,
        // 			"refName": "!",
        // 			"signalName": "clk",
        // 			"module": "test_tb",
        // 			"name": "test_tb.clk",
        // 			"wave": [
        // 				[
        // 					"0",
        // 					"0"
        // 				],
        // 				[
        // 					"20",
        // 					"1"
        // 				],
        // 				[
        // 					"40",
        // 					"0"
        // 				],
        // 				[
        // 					"60",
        // 					"1"
        // 				],
        // 				[
        // 					"80",
        // 					"0"
        // 				],
        // 				[
        // 					"100",
        // 					"1"
        // 				]
        // 			]
        // 		},
        // 		{
        // 			"type": "wire",
        // 			"size": 1,
        // 			"refName": "\"",
        // 			"signalName": "rst",
        // 			"module": "test_tb",
        // 			"name": "test_tb.rst",
        // 			"wave": [
        // 				[
        // 					"0",
        // 					"0"
        // 				],
        // 				[
        // 					"15",
        // 					"1"
        // 				]
        // 			]
        // 		}
        // 	]
        // }
    })
    .catch(err => {
        console.error(err);
    });

API Documentation

• VCDParser :
  • .parse(content, [opts], [cb]) ⇒ Promise.<ParsedData>

VCDParser.parse(content, [opts], [cb]) ⇒ Promise.<ParsedData>

Parse VCD text content and generate a valid JSON representation. The function returns a promise unless a callback is provided.

Returns: Promise.<ParsedData> - that resolves with the parsed data

Param	Type	Default	Description
content	string		The text content of the VCD file
[opts]	Options	{}	Optional configuration to customize the parsing process
[cb]	ParseCallback		Optional callback if you don't prefer to use promises

VCDParser:Options : Object

The optional configuration for the VCD parser

Properties

Name	Type	Description
compress	boolean	Compress the output wave by ignoring the unchanged values
expandAmbigousBus	boolean	If the bus has some ambigous value (z or x), it gets expanded to represent the whole bus signal

VCDParser:ParsedData : Object

The parsed VCD object generated by the parser

Properties

Name	Type	Description
[...meta]	string	The values of different initial meta-data, e.g. date, timescale..etc
endtime	string	The endtime of the simulation
scale	string	The time-scale unit of the simulation
signal	Array.<Signal>	The signal values of the simulation

VCDParser:Signal : Object

The object representing one signal data

Properties

Name	Type	Description
name	string	The full name of the signal
type	string	The type of the signal, e.g. wire, reg,..etc
size	number	The size/width of the signal in bits
refName	string	The reference for this signal used inside the VCD file
module	string	The name of the top module for which this signal belongs
wave	Array.<SignalValue>	The values of the signal at different points of time

VCDParser:SignalValue : Array.<number>

The value of a signal at a specific point of time, represnted as a tuple [time, value]

Properties

Name	Type	Description
0	number	The time of the event
1	number	The value of the signal at that event

VCDParser:ParseCallback : function

The callback for the parsing function.

Param	Type	Description
err	error	The error generated while parsing
parsedJSON	ParsedData	The JSON document generated by the parser