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 and unalterably numbered during manufacture. There are 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 scheme uses a single
bus master and multiple
slaves on
the same wire. The bus master initiates all communication. The slaves can be
individually discovered and addressed using their unique ID.
Bus masters come in a variety of configurations including serial, parallel, i2c,
network or USB adapters.
OWFS design¶
OWFS is a suite of programs that designed to 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 are represented as simple files that can be read and
written.
Details of the individual slave or master design are hidden behind a consistent
interface. The goal is to provide an easy set of tools for a software designer
to create monitoring or control applications. There are some performance
enhancements in the implementation, including data caching, parallel access to
bus masters, and aggregation of device communication. Still the fundemental
goal has been ease of use, flexibility and correctness rather than speed.
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¶
TCP port or IPaddress:port for
owtap
Other OWFS programs will access owtap via this address. (e.g. owdir -s IP:port
/)
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)
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)