Extension File Format

Extensions are composed of at least three files, extension.json, readme.md, and one or more python files. The Logic 2 software uses Python version 3.8.

extension.json File Layout

A single extension can contain multiple high level analyzers, measurements, or both.

This example is a for a single extension that contains one high level analyzer and one digital measurement.

{
  "version": "0.0.1",
  "apiVersion": "1.0.0",
  "author": "Mark Garrison",
  "description": "Utilities to measure I2C speed and utilization",
  "name": "I2C Utilities",
  "extensions": {
    "I2C EEPROM Reader": {
      "type": "HighLevelAnalyzer",
      "entryPoint": "I2cUtilities.Eeprom"
    },
    "I2C clock speed measurement": {
      "type": "DigitalMeasurement",
      "entryPoint": "I2cUtilities.I2cClock",
      "metrics": {
        "i2cClockSpeed": {
          "name": "I2C Clock Speed",
          "notation": "N MHz"
        },
        "i2cBusUtilization": {
          "name": "I2C Bus Utilization",
          "notation": "N %"
        }
      }
    }
  }
}

The author, description, and name properties manage what appears in the Extensions panel where the extensions are managed.

Property	Example	Description
version	"0.0.1"	The version if this extension. Increase this when publishing updates in order to allow users to update.
apiVersion	"1.0.0"	The Saleae API version used. This should remain "1.0.0" until we make changes to the extension API.
author	"Mark Garrison"	Your name
description	"Utilities to measure I2C..."	A one line description for display in the marketplace
name	"I2C Utilities"	The name of the extension package, for display. Note - this does not have to match the names of the individual extensions, which are shown elsewhere.
extensions	see below	An object with one key per high level analyzer or measurement.

The extensions section describes each high level analyzer or measurement that is contained in this extension package.

In the example above, there are 2 extensions listed.

  "extensions": {
    "I2C EEPROM Reader": {
      "type": "HighLevelAnalyzer",
      "entryPoint": "I2cUtilities.Eeprom"
    },
    "I2C clock speed measurement": {
      "type": "DigitalMeasurement",
      "entryPoint": "I2cUtilities.I2cClock",
      "metrics": {
        "i2cClockSpeed": {
          "name": "I2C Clock Speed",
          "notation": "N MHz"
        },
        "i2cBusUtilization": {
          "name": "I2C Bus Utilization",
          "notation": "N %"
        }
      }
    }
  }

There are three different types of extension here, as indicated by the type property. "HighLevelAnalyzer", "DigitalMeasurement", and "AnalogMeasurement". There are some differences between these types.

Type: HighLevelAnalyzer

Property	Example	Description
type	"HighLevelAnalyzer"	This must be the string "HighLevelAnalyzer"
entryPoint	"I2cUtilities.Eeprom"	The python entry point. The first part is the python filename without the extension, and the second part is the name of the class in that file

Type: AnalogMeasurement and DigitalMeasurement

Property	Example	Description
type	"DigitalMeasurement"	This must be either "DigitalMeasurement" or "AnalogMeasurement"
entryPoint	"I2cUtilities.I2cClock"	The python entry point. The first part is the python filename without the extension, and the second part is the name of the class in that file
metrics	"i2cClockSpeed": { "name": "I2C Clock Speed", "notation": "N MHz" }	Object that contains one property for each single numeric metric you wish to display. If your measurement class produces 4 different numbers, all 4 must be present here. Each metric property name must match the name of the metric produced by your python class.
metrics[X].name	"I2C Clock Speed"	The display name for a given metric
metrics[X].notation	"N MHz"	The display string for formatting the metric. Limited HTML tags are supported: ['b', 'i', 'em', 'strong', 'sub'] Example: "N <sub>t</sub>"