Apps Serial communication over FTDI FT231X

[Kailash Chandra Dhaker]

Seeking for solution badly
====================

I am creating app for electric meter reading
When i am using below code for communication

UsbSerialDevice serialPort = UsbSerialDevice.createUsbSerialDevice(device, connection);
serialPort.open()
serialPort.setBaudRate(9600);
serialPort.setDataBits(UsbSerialInterface.DATA_BITS_8);
serialPort.setStopBits(UsbSerialInterface.STOP_BITS_1);
serialPort.setParity(UsbSerialInterface.PARITY_NONE);
serialPort.setFlowControl(UsbSerialInterface.FLOW_CONTROL_OFF);
serialPort.read(mCallback);

On writing data with serialPort.write("S\r\n".getBytes());
It gives me serial number of the meter.
But as per our meter communication protocol i want to write data and read synchronously particular bytes from meter as per below code

Set connection
UsbDeviceConnection connection =
                    usbManager.openDevice(device);
            if (connection != null &&
                    connection.claimInterface(usbInterfaceFound, true)) {
                 int result =  connection.controlTransfer(0x40, 0, 0, 0, null, 0, 0);// reset
                Common.writeToLog("connection.controlTransfer(0x40, 0, 0, 0 "+String.valueOf(result));
                result =  connection.controlTransfer(0x40, 0, 1, 0, null, 0, 0);// clear Rx
                Common.writeToLog("connection.controlTransfer(0x40, 0,1, 0 "+String.valueOf(result));
                result =    connection.controlTransfer(0x40, 0, 2, 0, null, 0, 0);// clear Tx
                Common.writeToLog("connection.controlTransfer(0x40, 0, 2, 0 "+String.valueOf(result));
                result =    connection.controlTransfer(0x40, 0x02, 0x0002, 0, null, 0, 0); // flow control none
                Common.writeToLog("connection.controlTransfer(0x40, 0x02, 0, 0 "+String.valueOf(result));

            /*
            * Calculate a Divisor at 48MHz 9600 : 0x4138 11400 : 0xc107 19200 : 0x809c
            * 38400 : 0xc04e 57600 : 0x0034 115200 : 0x001a 230400 : 0x000d
         */
                result =    connection.controlTransfer(0x40, 0x03, 0x4138, 0, null, 0, 0);
                Common.writeToLog("connection.controlTransfer(0x40, 0x03, 0, 0 "+String.valueOf(result));

                result =    connection.controlTransfer(0x40, 0x04, 0x0008, 0, null, 0, 0); // n/8/1
                Common.writeToLog("connection.controlTransfer(0x40,0x04, 0x0008, 0 "+String.valueOf(result));
                }

public void writeData(byte[] message)
{
    message=new byte[1024];
    message[0]=1;
    message[1]=0;
    message[2]=1;
    message[3]=0;
    message[4]=12;
    message[5]=4;
    message[6]=54;
    message[7]=(byte)253;
    Common.writeToLog("usbDeviceConnection "+String.valueOf(usbDeviceConnection));
    synchronized (this) {
        if (usbDeviceConnection != null) {
            Common.writeToLog("data before write "+Common.bytesToHex(message));
            int result= usbDeviceConnection.bulkTransfer(endpointOut,
                    message, message.length, 30000);
            Common.writeToLog("bulkTransfer read result of writeData"+String.valueOf(result));
            Common.writeToLog("data after write "+Common.bytesToHex(message));
        }
    }
}
public void readData(byte[] message, int offset, int length)
{
    synchronized (this) {
        if (usbDeviceConnection != null) {
            Common.writeToLog("data before read "+Common.bytesToHex(message));
           int result= usbDeviceConnection.bulkTransfer(endpointIn,
                    message,length, 30000);
            Common.writeToLog("bulkTransfer read result of readData "+String.valueOf(result));
            Common.writeToLog("data after read "+Common.bytesToHex(message));
        }
    }
}

but in readData method i always got -1 in result

Source code is also attached

 

[Unforgiven]

Hi,
I moved your thread to the development area where you are more likely to get help. I also put your code inside code tags so they are easier to read. Good luck getting the problem sorted.

 

[Deleted User]

Is your message buffer big enough to accommodate the number of bytes you're asking for?

The Javadocs don't give much help on why this method would return -1. Just says "failure". Big help.

https://developer.android.com/refer...bulkTransfer(android.hardware.usb.UsbEndpoint, byte[], int, int)