@cutos/drivers

Introduction

Developing with a serial port simulator is a convenient, safe, and efficient way to develop drivers. It does not require real devices and is easier to control the test environment. It is especially suitable for the early development stage and development that requires various test scenarios. It is used to simulate the hardware behavior of the serial port, including receiving and sending data, control signals, etc.
The Serialport class is used to handle serial port communication. It uses the serial port path, baud rate, callback function, and simulator to create a new serial port object.
The SerialPortSimulator class creates a new serial port simulator to simulate serial port behavior.

Table of Contents

• SerialPort
• Native Lib
• DeviceSimulator
• NativeLibSimulator
• SerialPortSimulator

Serial port

Serial port: an extended interface using serial communication.

Serial port communication: a communication method in which the serial port sends and receives bytes bit by bit.

The Serialport class is used to handle serial port communication. It creates a new serial port object using the serial port path, baud rate, callback function, and simulator. It is used to simulate serial port communication data.

Installation

npm install @cutos/drivers

Introduce dependencies

const {SerialPort} = require("@cutos/drivers");

Serialport

constructor(path, baudRate, callback = null, simulator = null)

• path: port path
• baudRate: baud rate
• callback: callback function
• simulator: simulator instance

Example:

The driver creates a new serialport instance and returns the port result, which is often used in device connection related methods.

let serialport = new SerialPort('/dev/ttySS3', 19200, error => {
    if (error) {
        console.log(error)
    }
}, simulator)

Methods from the base class SerialPortStream

See @serialport/stream

• write
• on('data')

Native Lib

Local libraries, such as ID card reader devices, require calling local dll libraries.

Installation

npm install @cutos/drivers

Introduce dependencies

const {NativeLib} = require("@cutos/drivers");

NativeLib

constructor(lib_path, simulator = null)

• lib_path: shared library path
• simulator: device simulator

Example:

let lib = new NativeLib('ghcmio.dll');

NativeLib.func

Find function

NativeLib.func(declaration);

• declaration: function declaration

Reference KOFFI

Example:

this.lib.func('size_t __stdcall mio_open(char* psport, char* psexport, int32_t baud)') 

DeviceSimulator

DeviceSimulator is the base class for simulator development. Currently, there are two derived classes: SerialPortSimulator and NativeLibSimulator.

DeviceSimulator

Constructor

constructor(config, state)

• config: configuration parameters
• state: initial state

DeviceSimulator.getInfo

Function that provides information to the simulator. Currently supported information includes: README.md and protocol.

Need to be rewritten in the derived class of the specific device simulator.

Return result {readme, doc}

Example:

getInfo()
{
    let readme = fs.readFileSync(path.join(__dirname, 'README.md'), 'utf-8');
    let doc = fs.readFileSync(path.join(__dirname, 'doc.pdf'), 'base64');
    return {readme, doc}
}

DeviceSimulator.onEmitEmptyCommand

When the emit command without parameters is used in the console, this function will be called to send default data to the driver.

Need to be overridden in the derived class of the specific device simulator.

SerialPortSimulator

Developing with a serial port simulator is a convenient, safe, and efficient way to develop drivers. It does not require real devices and is easier to control the test environment. It is especially suitable for the early development stage and development that requires various test scenarios. It is used to simulate the hardware behavior of the serial port, including receiving and sending data, control signals, etc. SerialPortSimulator inherits from DeviceSimulator.

SerialPortSimulator

Constructor, create a serialPortSimulator instance

constructor(config, state = null)

• config: configuration parameters
• state: initial state

SerialPortSimulator.onOpen

Port opening event.

If the derived class needs to handle the event after the port is opened, rewrite this function.

SerialPortSimulator.onReceiveData

Receive data from the driver, and the driver uses the SerialPort.write(data) method to send data.

Derived classes need to rewrite this function to handle their own protocols.

serialPortSimulator.onReceiveData(data)

• data: received data, type is Buffer

SerialPortSimulator.emitData

Send data to the driver, parameter data type is Buffer. The driver receives data in the SerialPort.on('data',(data)=>{}) function.

serialPortSimulator.emitData(data)

• data: emit data, type is Buffer

Example:

serialPortSimulator.emitData(Buffer.from([0xF5, 0x09, 0x00, 0x00, 0x00, 0x00, 0x09, 0xF5]))

The following takes the physical examination body height device driver as an example to introduce the development of the simulator

Name	Description	Download
device-height-weight-scale-v3.3.3	Physical examination body height and weight device driver	Download

simulator/device-height-weight-scale-simulator.js

const fs = require('node:fs');
const {Buffer} = require("node:buffer");
const path = require('node:path');
const config = require('../config.json');
const {SerialPortSimulator} = require('@cutos/drivers')
const {request, response} = require('../device-height-weight-scale-protocol')


class DeviceHeightWeightScaleSimulator extends SerialPortSimulator {

    constructor() {
        super(config, {height: 170, weight: 70});
        this.responsing = false;
    }

    switchOn() {
        if (this.timer) return
        this.timer = setInterval(() => {
            if (!this.responsing) {
                let weight = +this.state.weight
                this.emitData(response.generate_weight_data(weight))
            }
        }, 1000)
    }

    switchOff() {
        clearInterval(this.timer)
    }

    onReceiveData(data) {
        this.responsing = true
        if (!Buffer.compare(request.GET_HEIGHT_WEIGHT, data)) {
            let count = 0
            let timer = setInterval(() => {
                let height = +this.state.height
                let weight = +this.state.weight
                this.emitData(response.generate_height_weight_data(height, weight))
                if (++count === 3) {
                    clearInterval(timer)
                    this.responsing = false
                }
            }, 1000)
        }
        if (!Buffer.compare(request.SWITCH_ON, data)) {
            this.switchOn()
            this.emitData(response.SWITCH_ON)
            this.responsing = false
        }

        if (!Buffer.compare(request.SWITCH_OFF, data)) {
            this.switchOff()
            this.emitData(response.SWITCH_OFF)
            this.responsing = false
        }
    }

    getInfo() {
        const readme = fs.readFileSync(path.join(__dirname, 'README.md'), 'utf8')
        return {readme}
    }
}

module.exports = {
    DeviceHeightWeightScaleSimulator
}

NativeLibSimulator

NativeLibSimulator inherits from DeviceSimulator and is used for simulators with local dependency libraries, such as simulators for ID card reader devices.

NativeLibSimulator

Constructor

constructor(config, state = null)

• config: configuration parameters
• state: initial state

SerialPortSimulator

SerialPortSimulator

Constructor, create a serialPortSimulator instance

let serialPortSimulator = new DeviceNFCSimulator(name);

• name: simulator name, determine whether to use the simulator by the name.

Example:

sdk creates a device

let device = new DeviceFingerprint('mock');

Driver development uses the simulator

if (name === 'mock') {
    this.simulator = new DeviceFingerprintSimulator()
}

serialPortSimulator.onOpen

The listening port is open and can be used to perform certain operations

serialPortSimulator.onOpen()

serialPortSimulator.emitData

Emit serialPortSimulator data

serialPortSimulator.emitData(data)

• data: emit data

Example:

serialPortSimulator.emitData(Buffer.from([0xF5, 0x09, 0x00, 0x00, 0x00, 0x00, 0x09, 0xF5]))

serialPortSimulator.onEvent

Handle events

serialPortSimulator.onEvent(event, params, callback)

Example:

onEvent(event, params, callback)
{
    if (event === 'wake') {
        this.userID = params.id;
        this.emitData(Buffer.from([0xF5, 0x09, 0x00, 0x00, 0x00, 0x00, 0x09, 0xF5]))
        callback('success')
    } else {
        callback('unsupported event')
    }
} 

serialPortSimulator.getHelp

Get help

serialPortSimulator.getHelp()