Option Explicit On
Option Strict On
Imports System.IO.Ports
Imports System.Text


Public Class MainForm

    ' Demonstrates communications between a USBwiz-OEM board and a USB flash drive
    '  attached to the USBwiz-OEM.
    ' The Visual-Basic application functions as host software that sends commands 
    ' to the host controller in the USBwiz.
    ' Why use a PC to control the USB host controller on the USBwiz-OEM?
    ' The PC interface makes it easy to experiment with the code. 
    ' When the code is working, you can port it to any microcontroller with a UART port.

    ' I used a DLP Electronics DLP-USB232M module to interface the USBwiz's asynchronous serial
    ' port to a USB port on a PC. You can instead use a MAX233 or similar chip to connect the 
    ' USBwiz to an RS-232 port or a USB/RS-232 converter on a PC.

    ' Connections:
    ' USBwiz-OEM  DLP-USB232M

    '     1-----------23
    '     2-----------24
    '     6-----------21
    '     7-----------22

    ' USBwiz-OEM
    ' Connect pins 13, 14, 17, 18 to +5V.
    ' Connect pins 15, 16 to GND.

    ' DLP-USB232M
    ' Connect pins 3, 10, 11, 14 to +5V.
    ' Connect pins 2, 5, 7, 19 to GND.

    ' Use a regulated +5V supply.
    ' Attach a flash drive to the bottom USB connector on the USBwix-OEM.

    ' For more about the USBwiz, go to ghielectronics.com.
    ' For more about USB and mass storage, go to Lvr.com.
    ' Send error reports, comments, etc. to jan@Lvr.com

    ' By Jan Axelson
    ' Version 0.9

    Friend enumerated As Boolean
    Friend portChange As Boolean
    Friend previousPortIndex As Integer
    Friend receiveBuffer As String
    Friend selectedPort As New System.IO.Ports.SerialPort
    Friend selectedPortIndex As Integer


    Dim previousTime As Date
    Dim timeOfTransfer As String
    Dim transferInProgress As Boolean

    '******************************************************************************************
    ' Variables used in USBwiz commands.
    ' See the USBwiz manual for more info.

    Dim deviceHandle As String = "0"
    Dim fileHandle As String = "0"         ' Valid values: 0, 1, 2, 3.
    Dim fileName As String = "test.txt"    ' The file to write to and read.
    Dim fileSystem As String = "0"         ' Valid values: 0, 1, 2.

    ' Used by the RF command if the file being read is shorter than the requested data.
    Dim fillerSymbol As String = " "

    Dim lun As String = "0"                ' Many drives have only LUN 0.
    Dim massStorageHandle As String = "0"
    Dim usbPort As String = "0"            ' Port 0 is the bottom connector on the USBwiz-OEM board.

    '******************************************************************************************

    ' USBwiz success code.
    Const Success As String = "!00"

    'Used in error messages.
    Const ModuleName As String = "USBwiz Demo"

    Private Sub btnEnumerateDrive_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnEnumerateDrive.Click

        ' Enumerate the drive and assign handles.

        InitializeDriveCommunications()
    End Sub

    Private Sub btnReadFromFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnReadFromFile.Click

        ' Read from a file on the flash drive.

        ReadFromFile()

    End Sub

    Private Sub btnWriteToFile_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnWriteToFile.Click

        'Write to a file on the flash drive.

        WriteToFile()

    End Sub
    Private Sub CloseComPort()
        If (Not IsNothing(selectedPort)) Then
            If selectedPort.IsOpen Then
                selectedPort.Dispose()
            End If
        End If
    End Sub

    Private Sub CloseDeviceHandle()

        ' Purpose    : close the device handle.
        '              The application will need to re-enumerate the device to resume communicating.

        Dim command As String
        Dim response As String

        txtMonitor.AppendText("Closing the device handle." + vbCrLf)

        If Enumerated Then
            command = "UR " + deviceHandle
            response = SendCommandToUsbwiz(command)
        End If

        enumerated = False
        transferInProgress = False

    End Sub

    Private Function DisplayDateAndTime() As String

        ' Purpose    : get and format the current date and time.

        ' Returns    : the data and time.

        Dim DateAndTime As Date = DateTime.Now
        Dim DateAndTimeString As String = ""

        DateAndTimeString = DateAndTime.ToString("G")

        Return DateAndTimeString

    End Function

    Private Sub DisplayFailureMessage(ByVal command As String, ByVal response As String)

        ' Purpose    : display a failure message in a text box.

        ' Accepts    : command - the command that failed
        '              response - the response code 

        txtMonitor.AppendText _
        ("Failed executing command " + command + " with response = " + response + "." + vbCrLf)

    End Sub

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Show()

        MyMainForm = Me
        MyPortSettings = New PortSettings

        transferInProgress = False

        InitializeDisplayElements()
        MyPortSettings.InitializePortSettings()

    End Sub

    Private Function ReadFileContents(ByRef receivedData As String, ByRef bytesRead As Integer, ByVal bytesToRead As Integer) As String

        ' Purpose    : Gets the requested number of bytes from the receive buffer.

        ' Accepts    : receivedData - a string to hold the received bytes.
        '              bytesRead - the number of bytes returned.
        '              bytesToRead - the number of bytes requested. 

        ' Returns    : USBwiz response code

        Dim byteBuffer() As Byte
        Dim incomingData As String = ""
        Dim newData As String = ""
        Dim response As String = ""
        Dim totalBytesRead As Integer

        ' Set the size of the buffer to match the number of bytes to read.
        ReDim byteBuffer(bytesToRead - 1)

        Do
            ' Read the port until we have the requested number of bytes or a timeout.
            bytesRead = selectedPort.Read(byteBuffer, 0, bytesToRead - totalBytesRead)

            ' Keep track of how many bytes have been read.
            totalBytesRead = totalBytesRead + bytesRead

            ' Save the data read as a string.
            newData = Encoding.Default.GetString(byteBuffer, 0, bytesRead)

            ' Append the new data to any previously read data.
            receivedData = receivedData + newData

        Loop Until (totalBytesRead >= bytesToRead)

        'The USBwiz follows the requested data with the number of valid bytes returned.
        response = ReadDataFromUsbwiz(CStr(bytesRead))

        Return response

    End Function

    Private Sub InitializeDisplayElements()

        ' Purpose    : initialize elements on the main form.

        ' Textbox elements:
        txtMonitor.Multiline = True
        txtMonitor.ScrollBars = ScrollBars.Vertical
        txtMonitor.AcceptsReturn = True
        txtMonitor.AcceptsTab = True
        txtMonitor.WordWrap = True
        txtMonitor.Multiline = True

    End Sub

    Private Sub InitializeDriveCommunications()

        ' Purpose    : Send commands to the USBwiz to enumerate a drive and mount a file system.

        Dim command As String = ""
        Dim freeMedia As String = ""
        Dim response As String = ""
        Dim maxLun As String = ""
        Dim mediaSize As String = ""
        Dim mediaStatistics As String = ""
        Dim stringIndex As Integer

        Try
            transferInProgress = True
            txtMonitor.Clear()

            ' Open the COM port if necessary.

            If portChange Then

                ' The user has changed the selected COM port.
                portChange = False

                ' If a previously opened port is open, close it.
                CloseComPort()

                ' Open the new selected port.
                OpenComPort()
            Else
                If Not (IsNothing(selectedPort)) Then
                    If Not (selectedPort.IsOpen) Then

                        ' A port has been initialized but the port isn't open.
                        OpenComPort()
                    End If
                Else
                    ' A port hasn't been initialized or opened.
                    OpenComPort()
                End If
            End If

            enumerated = False

            ' Close the device handle if one was open.
            ' Returns success even if no handle was open.
            command = "UR " + deviceHandle
            response = SendCommandToUsbwiz(command)

            If (Not IsNothing(selectedPort)) Then
                If selectedPort.IsOpen Then

                    ' The port exists and is open.
                    command = "UI " + usbPort + ">" + deviceHandle
                    txtMonitor.AppendText _
                    ("Enumerating and assigning a device handle to the USB drive: " + command + vbCrLf)
                    response = SendCommandToUsbwiz(command)

                    If (response = Success) Then
                        command = "UM " + deviceHandle + ">" + massStorageHandle
                        txtMonitor.AppendText _
                        ("Registering the drive's device handle to a mass-storage handle: " + command + vbCrLf)
                        response = SendCommandToUsbwiz(command)

                        If (response = Success) Then
                            response = ReadDataFromUsbwiz(maxLun)
                            txtMonitor.AppendText("Max LUN = " + maxLun.Trim("$"c) + vbCrLf)

                            If (response = Success) Then
                                command = "AM U" + massStorageHandle + "<" + lun
                                txtMonitor.AppendText _
                                ("Attaching to a LUN of the USB drive: " + command + vbCrLf)
                                response = SendCommandToUsbwiz(command)

                                If (response = Success) Then
                                    command = "MU " + fileSystem + ">U" + massStorageHandle
                                    txtMonitor.AppendText _
                                    ("Mounting a file system on the mass-storage handle: " + command + vbCrLf)
                                    response = SendCommandToUsbwiz(command)

                                    If (response = Success) Then
                                        enumerated = True
                                        txtMonitor.AppendText _
                                        ("Ready to communicate with the drive." + vbCrLf)

                                        command = "MS"
                                        txtMonitor.AppendText _
                                        ("Requesting media statistics: " + command + vbCrLf)
                                        response = SendCommandToUsbwiz(command)
                                        response = ReadDataFromUsbwiz(mediaStatistics)

                                        ' Remove the first "$" in the response.
                                        mediaStatistics = mediaStatistics.Trim("$"c)

                                        ' Get the location of the second "$".
                                        stringIndex = mediaStatistics.IndexOf("$"c)

                                        ' Media size is everything up to the second "$".
                                        mediaSize = mediaStatistics.Substring(0, stringIndex - 1)
                                        txtMonitor.AppendText("Media size = " + CStr(Convert.ToInt32(mediaSize, 16)) + " bytes." + vbCrLf)

                                        ' Free media is what follows the second "$".
                                        freeMedia = mediaStatistics.Trim("$"c)
                                        freeMedia = mediaStatistics.Substring(stringIndex + 1, 8)
                                        txtMonitor.AppendText("Free media = " + CStr(Convert.ToInt32(freeMedia, 16)) + " bytes." + vbCrLf)
                                    Else
                                        DisplayFailureMessage(command, response)
                                    End If
                                Else
                                    DisplayFailureMessage(command, response)
                                End If
                            Else
                                DisplayFailureMessage(command, response)
                            End If
                        Else
                            DisplayFailureMessage(command, response)
                        End If
                    Else
                        DisplayFailureMessage(command, response)
                    End If
                Else
                    txtMonitor.AppendText("Unable to open the COM port.")
                End If
            Else
                txtMonitor.AppendText("The selected COM port doesn't exist.")
            End If

        Catch ex As TimeoutException
            txtMonitor.AppendText("Timeout" + vbCrLf)
            CloseDeviceHandle()

        Catch ex As InvalidOperationException
            txtMonitor.AppendText("Invalid operation" + vbCrLf)
            CloseDeviceHandle()
        Finally
            transferInProgress = False
        End Try

    End Sub

    Private Sub MainForm_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing

        CloseDeviceHandle()
        CloseComPort()
    End Sub

    Private Sub OpenComPort()

        ' Purpose    : open a COM port for communicating.