usbhelper.kt

package com.example.myapplication

import android.content.Context
import android.hardware.usb.UsbManager
import com.hoho.android.usbserial.driver.UsbSerialPort
import com.hoho.android.usbserial.driver.UsbSerialProber

fun openUsbSerial(context: Context): UsbSerialPort {
    val manager = context.getSystemService(Context.USB_SERVICE) as UsbManager

    val drivers = UsbSerialProber.getDefaultProber().findAllDrivers(manager)
    require(drivers.isNotEmpty()) { "No USB serial devices found" }

    val driver = drivers[0]
    val connection = manager.openDevice(driver.device)
        ?: error("USB permission denied or device could not be opened")

    val port = driver.ports[0]
    port.open(connection)
    port.setParameters(
        19200,
        8,
        UsbSerialPort.STOPBITS_1,
        UsbSerialPort.PARITY_NONE
    )

    return port
}