Android Question How to read and write data from multiple UART_USB (CH340 two ports)

Diego Marcelo Croatto · May 29, 2020

Hi to all.... I'm trying to read and write data from two USB Uarts (CH340) I'm using felUSBSerial(v1.12)

I have been able to connect of each port but when i receive data I cant identify from what device is incomming the data.

serial_DataAvailable:

Private Sub serial_DataAvailable (Buffer() As Byte)

This function receive the data from the two ports at the same time.... How I can do the identification of the data incomming from each port and prevent the colition of this data.

Thank's a Lot!!!!

DonManfred · May 29, 2020

Use two Serial Instances and listen to one port each?

Diego Marcelo Croatto · May 29, 2020

DonManfred said:
Use two Serial Instances and listen to one port each?

Ohhh God !... this excedes my capacity without examples. Thank's Don i continue trying or waiting another idea.

DonManfred · May 29, 2020

Use two instances. Give every instance a new EventPrefix (serial1, serial2)
Use two Event Subs

B4X:

Private Sub serial1_DataAvailable (Buffer() As Byte)
Private Sub serial2_DataAvailable (Buffer() As Byte)

Diego Marcelo Croatto · May 29, 2020

DonManfred said:
Use two instances. Give every instance a new EventPrefix (serial1, serial2)
Use two Event Subs

B4X:

Private Sub serial1_DataAvailable (Buffer() As Byte) Private Sub serial2_DataAvailable (Buffer() As Byte)

I create this code for open each port with:

device_0 and device_1 as each UsbDevice

usbserial_0 and usbserial_1 as each UsbSerial

but I dont understand what is the event of each port

Globals:

    Private manager As UsbManager
    
    Private device_0 As UsbDevice
    Private device_1 As UsbDevice
    
    Private usbserial_0 As felUsbSerial
    Private usbserial_1 As felUsbSerial

    Private felAST_0 As felAsyncStreamsText
    Private felAST_1 As felAsyncStreamsText

OpenPorts:

    '******************************************************************
    ' Initialize the USB Ports
    '******************************************************************

    felAST_0.Initialize(Me,"felAST")
    felAST_1.Initialize(Me,"felAST")
    
    Dim Tmp,Tmp1 As Int
        
    If manager.GetDevices.Length = 0 Then
        Log("No connected usb devices.")
    Else

        device_0= manager.GetDevices(CH340_Port_0) 'first Channel
        device_1= manager.GetDevices(CH340_Port_1) 'second Channel
            
        If manager.HasPermission(device_0) = False Then
            ToastMessageShow("Please allow connection and click again.", True)
            manager.RequestPermission(device_0)
        Else
            usbserial_0.Initialize("serial", device_0, -1)
            usbserial_0.BaudRate = 9600
            usbserial_0.DataBits = usbserial_0.DATA_BITS_8
            usbserial_0.StartReading
        End If

        If manager.HasPermission(device_1) = False Then
            ToastMessageShow("Please allow connection and click again.", True)
            manager.RequestPermission(device_1)
        Else
            usbserial_1.Initialize("serial", device_1, -1)
            usbserial_1.BaudRate = 9600
            usbserial_1.DataBits = usbserial_1.DATA_BITS_8
            usbserial_1.StartReading
        End If
        
    End If

DonManfred · May 29, 2020

Diego Marcelo Croatto said:
felAST_0.Initialize(Me,"felAST") felAST_1.Initialize(Me,"felAST")

B4X:

felAST_1.Initialize(Me,"felAST1") ' Same for port 2
felAST_2.Initialize(Me,"felAST2")

Diego Marcelo Croatto · May 29, 2020

DonManfred said:
B4X:

felAST_1.Initialize(Me,"felAST1") ' Same for port 2 felAST_2.Initialize(Me,"felAST2")

Ok... Its the same....but where point "data available"

DonManfred · May 29, 2020

For THIS prefix you need to use similar event subs

B4X:

Private Sub FelAST1_DataAvailable (Buffer() As Byte)
Private Sub FelAST2_DataAvailable (Buffer() As Byte)

PD: I strongly suggest to read the Documentation, watch some Videos to learn the basics.

Diego Marcelo Croatto · May 29, 2020

Don .... Thank's a lot... I have discovered the event!!!!

felUsbSerial:

usbserial_0.Initialize("serial_0", device_0, -1)    'Port 0'
usbserial_1.Initialize("serial_1", device_1, -1)    'Port 1'

"serial_0" and "serial_1 is the event! ...☝

Erel · May 31, 2020

Another (in most cases better) way to do it is by implementing it in a class and creating two or more instances of this class.

Android Question How to read and write data from multiple UART_USB (CH340 two ports)

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