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 |