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Name

owtap - Packet sniffer for the owserver protocol

Synopsis

owtap -p owtap-tcp-port -s owserver-tcp-port

Description

1-Wire

1-wire is a wiring protocol and series of devices designed and manufactured by Dallas SemicondUctor, Inc. The bus is a low-power low-speed low-connector scheme where the data line can also provide power.

Each device is uniquely unalterably numbered during manufacture. There is a wide variety of devices, including memory, sensors (humidity, temperature, voltage, contact, current), switches, timers and data loggers. More complex devices (like thermocouple sensors) can be built with these basic devices. There are also 1-wire devices that have encryption included.

The 1-wire bus is accessed via one of a number of serial, parallel, i2c, network or USB adapters.

OWFS design

OWFS is a suite of programs that fundementally make the 1-wire bus and its devices easily accessible. The underlying priciple is to create a virtual filesystem, with the unique ID being the directory, and the individual properties of the device files.

There is optional data caching to improved performance, but possible confusion over stale data.

owserver

owserver (1) is the backend component of the OWFS 1-wire bus control system. owserver (1) arbitrates access to the bus from multiple client processes. The physical bus is usually connected to a serial or USB port, and other processes connect to owserver (1) over network sockets (tcp port).

Frontend clients include a filesystem representation: owfs (1) , and a webserver: owhttpd (1) . Direct language bindings are also available, e.g: owperl (3) .

There are also many light-weight clients that can only talk to owserver (1) and not to the 1-Wire bus directly. They include shell and multiple language modules (perl, Visual Basic, python,...)

owserver protocol

All the owserver (1) clients use the owserver protocol for communication. The owserver protocol is a well documented tcp/ip client/server protocol. Assigned the "well known port" default of 4304.

owtap

owtap (1) is interposed between owserver (1) and clients, to display and help resolve communication problems. Network communication is forwarded in both directions, but a visual display is also created, with statistics and "drill-down" of individual packets.

Specific Options

-p

TCP port or IPaddress:port for owtap
Other OWFS programs will access owtap via this address. (e.g. owdir -s IP:port /)

-s

TCP port or IPaddress:port for owserver
The tcp port (IP:port) for the "upstream" owserver.

Example

If owserver (1) is started:
owserver -p 4304 -d /dev/ttyS0
owserver on tcp port 4304 and connects to a physical 1-wire bus on a serial port.

You can directly query owserver (1) with
owdir -s 4304 /

To see the protocol in action:
owtap -s 4304 -p 3000
owdir -p 3000 /

In this case owtap (1) is connecting to owserver (1) on the original port (4304) and offering a new port (3000) for clients.

Platfoms

owtap (1) is a pure Tcl/TK program and will run whereever Tcl/TK is available (Windows, Macintosh, Linux, Unix)

Links

owserver protocol

http://www.owfs.org/index.php?page=owserver-protocol

Tcl/TK

http://www.tcl.tk

See Also

Programs

owfs (1) owhttpd (1) owftpd (1) owserver (1) owdir (1) owread (1) owwrite (1) owpresent (1) owtap (1)

Configuration and testing

owfs (5) owtap (1) owmon (1)

Language bindings

owtcl (3) owperl (3) owcapi (3)

Clocks

DS1427 (3) DS1904(3) DS1994 (3) DS2404 (3) DS2404S (3) DS2415 (3) DS2417 (3)

ID

DS2401 (3) DS2411 (3) DS1990A (3)

Memory

DS1982 (3) DS1985 (3) DS1986 (3) DS1991 (3) DS1992 (3) DS1993 (3) DS1995 (3) DS1996 (3) DS2430A (3) DS2431 (3) DS2433 (3) DS2502 (3) DS2506 (3) DS28E04 (3) DS28EC20 (3)

Switches

DS2405 (3) DS2406 (3) DS2408 (3) DS2409 (3) DS2413 (3) DS28EA00 (3)

Temperature

DS1822 (3) DS1825 (3) DS1820 (3) DS18B20 (3) DS18S20 (3) DS1920 (3) DS1921 (3) DS1821 (3) DS28EA00 (3) DS28E04 (3)

Humidity

DS1922 (3)

Voltage

DS2450 (3)

Resistance

DS2890 (3)

Multifunction (current, voltage, temperature)

DS2436 (3) DS2437 (3) DS2438 (3) DS2751 (3) DS2755 (3) DS2756 (3) DS2760 (3) DS2770 (3) DS2780 (3) DS2781 (3) DS2788 (3) DS2784 (3)

Counter

DS2423 (3)

LCD Screen

LCD (3) DS2408 (3)

Crypto

DS1977 (3)

Pressure

DS2406 (3) -- TAI8570

Availability

http://www.owfs.org

Author

Paul Alfille (paul.alfille@gmail.com)


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