Android Question UsbSerial library 2.0 problem

[mrossen]

Hi

When I set the baudrate to 115200 the "LastException.Message" in "AStreams_Error" gives me a "java.io.IOException: Expected at least 2 bytes".

With ex. a baudrate 57600 the is no error but of course the data is garbage.

Anyone tried the library with a baudrate of 115200.

I use a profilic 2303 usb to serial cable

my code :

If usb.UsbPresent(1) = usb.USB_NONE Then
                Log("Msgbox - no device")
                Msgbox("No USB device or accessory detected!", "Error")
                Log("Msgbox - returned")
                Return
            End If
            
            Log("Checking permission")
            
            If (usb.HasPermission(1)) Then
                'Msgbox(usb.DeviceInfo(1), "Device Information")
                Dim dev As Int
                dev = usb.Open(115200, 1)
                If dev <> usb.USB_NONE Then
                    Log("Connected successfully!")
                    AStreams.Initialize(usb.GetInputStream, usb.GetOutputStream, "Astreams")
                Else
                    Log("Error opening USB port")
                End If
            Else
                usb.RequestPermission(1)
            End If

Mogens

 

[Erel]

Worth trying with felUsbSerial.

 

[mrossen]

I have tried felUsbSerial. I works perfect , but I can not set the retrieve buffer to a less size.

I tried :

Dim r As Reflector
r.SetStaticField("com.felhr.usbserial.SerialBuffer", "DEFAULT_READ_BUFFER_SIZE", 2048, "java.lang.int")

But it will not work

In this threed you advise to use usbserial insted. https://www.b4x.com/android/forum/threads/felusbserial-alternative-usb-serial-library.62216/page-4

The threed is from 2016 so maybe this can be done now?



Mogens

 

[Erel]

Why is this a problem?

 

[mrossen]

The problem is that I receive chunks of 15872k byte. I need the receive event raised much faster. When I receive data from Wifi I receive data with 8 to 40 bytes.

If I can set the buffer to ex. 1500 byte that will be fine.

Mogens

 

[Erel]

Please try the attached jar. You should see a message in the logs about the buffer size. It is hard coded to 1500. I want to see whether it makes any difference.

 

[mrossen]

Hi Erel,

This works perfect. Now I recieve 1426 byte. Is it possible to add this to the library so it can be changed?

Mogens

 

[Erel]

Implemented in v1.12.