Driver installation and usage

For digital thermometer and 1-wire adapter DS9097 with DS18B20 digital probe attached.

Lines started with $ or C:\> indicate start of commands that have to be typed in.

Linux driver

Driver for PL-2303TA serial interface is already included in mainline Linux Kernel.

In most cases, after pluging the USB device into USB port, the system will automatically load a driver.

$ dmesg | tail
usb: new full-speed USB device number 24 using ehci-pci
usb: New USB device found, idVendor=067b, idProduct=2303
usb: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb: Product: USB-Serial Controller
usb: Manufacturer: Prolific Technology Inc.
pl2303: pl2303 converter detected
usb: pl2303 converter now attached to ttyUSB0

Right at the end of dmesg output you should see something like the 7 lines above. This means that the thermometer has been recognised by the pl2303 driver.

You can check whether driver has been loaded if the last two lines appear.

$ lsmod |grep pl2303
pl2303                 16384  0 
usbserial              28672  1 pl2303


If the driver is not included into kernel, it has to be selected and then, depending on your system, the kernel recompiled or the module compiled.

Vanilla Linux Kernel
Device Drivers --->
	[*] USB support  --->
		<M> USB Serial Converter support  --->
			<M> USB Prolific 2303 Single Port Serial Driver

On the configuration menu of OpenWrt the following modules have to be selected.

Kernel modules  --->
	USB Support  --->
		<M> kmod-usb-serial
			<M> kmod-usb-serial-pl2303

Or in .config file:


Debian & Ubuntu

It is assumed that /dev/ttyUSB0 is the USB device.


$ sudo apt-get install digitemp
Initialize probe

Initialization is only needed for the first time.

$ digitemp_DS9097 -i -s /dev/ttyUSB0 
DigiTemp v3.6.0 Copyright 1996-2007 by Brian C. Lane
GNU General Public License v2.0 -
Turning off all DS2409 Couplers
Searching the 1-Wire LAN
28FFDB3F31170422 : DS18B20 Temperature Sensor
ROM #0 : 28FFDB3F31170422
Wrote .digitemprc

If you want to save configuration to a different file, use -c switch.

Acquire temperature
$ digitemp_DS9097 -a 
DigiTemp v3.6.0 Copyright 1996-2007 by Brian C. Lane
GNU General Public License v2.0 -
Feb 01 10:45:36 Sensor 0 C: 22.25 F: 72.05


Install software package.

$ sudo apt-get install owfs

Mount 1-wire filesystem.

$ mkdir ~/1w
$ owfs --passive /dev/ttyUSB0 ~/1w

List all 1-wire devices.

$ ls ~/1w/

The temperature probe starts with 28.:

$ cat ~/1w/28.FFDB3F311704/type 

Display the temperature.

$ cat ~/1w/28.FFDB3F311704/temperature

server: passive = /dev/ttyUSB0


For installation see Maxim's application note 5917.


Make sure you have build-in support for pl2303 driver, otherwise kernel image (and Openwrt image) must be recompiled (and router reflashed). In some cases, installing via opkg might work: opkg install kmod-usb-serial-pl2303


Install package digtemp: opkg install digitemp. If the package is not available follow manual at openwrt-packages-digitemp.

Before last step make sure you have CONFIG_PACKAGE_digitemp=y in .config file and you have ran make menuconfig. In LEDE the last step must be make package/feeds/hnw_digitemp/digitemp/compile

Usage is similar to that one for Debian.


Install package owfs: opkg install owshell owfs

See tutorial for Debian

Windows driver

The following pictures are based on Windows 7. The same procedure applies for recent versions of Windows.

In some cases Windows automatically detects USB serial interface. If it does not, a manual installation of drivers is needed.

PL2303 Driver installation

After installation open Device Manager and under Ports (COM & LPT) read name of new serial port. In next example, the serial port has name COM4 and number 4.

Device Manager

Windows 7

In following examples it is assumed that the device appeared under COM4 serial port.


Download digitemp.exe and open command prompt cmd. Navigate prompt to a directory where digitemp executable is located.

Initialize probe

Initialization is only needed for the first time. Number after -s flag represents serial port number.

C:\> digitemp.exe -i -s4
Acquire temperature
C:\> digitemp.exe -a


This application uses drivers from Maxim, so these must be installed first.

Maxim drivers installation

Continue with installation of LogTemp.

Logtemp installation

In the configuration set Adapter to DS9097E and Port COM to match your serial port name.

Logtemp config

To start taking measurments click Go on toolbar.

Logtemp systray display


This application requires Java RTE to be installed on the system.

Extract two files: OneWireViewer.jar and OneWireAPI.jar to a folder. Then navigate Windows Command Line to folder and execute.

java -classpath OneWireViewer.jar;OneWireAPI.jar;. OneWireViewer

In the setup window make sure DS9097E tab is selected and set Select Port to match your serial port name.

OneWireViewer Setup

After two more click to Next, a new window appears where 1-wires are given on left pane.