OWNet - Man Page

new

 my $owserver = OWNet -> new( address ) ;

read

 OWNet::read( address, path [,size [,offset]] )
 $owserver -> read( path [,size [,offset]] )

write

 OWNet::write( address, path, value [,offset] )
 $owserver -> write( path, value [,offset] )

dir

 OWNet::dir( address, path )
 $owserver -> dir( path )

TCP/IP address of owserver. Valid forms:

name test.owfs.net:4304

quad number: 123.231.312.213:4304

host localhost:4304

port 4304

Additional arguments to add to address

Temperature scale can also be specified in the address. Same syntax as the other OWFS programs:

-C Celsius (Centigrade)

-F Fahrenheit

-K Kelvin

-R Rankine

Pressure scale can also be specified in the address. Same syntax as the other OWFS programs:

--mbar     millibar (default)

--atm      atmosphere

--mmHg     mm Mercury

--inHg     inch Mercury

--psi      pounds per inch^2

--Pa       pascal

Device display format (1-wire unique address) can also be specified in the address, with the general form of -ff[.]i[[.]c] (family id crc):

-ff.i   /10.67C6697351FF (default)

-ffi    /1067C6697351FF

-ff.i.c /10.67C6697351FF.8D

-ff.ic  /10.67C6697351FF8D

-ffi.c  /1067C6697351FF.8D

-ffic   /1067C6697351FF8D

Show directories that are themselves directories with a '/' suffix ( e.g. /10.67C6697351FF/ )

-slash  show directory elements

Warning messages will only be displayed if verbose flag is specified in address

-v      verbose

owfs-type path to an item on the 1-wire bus. Valid forms:

main directories

Used for the dir method. E.g. “/” “/uncached” “/1F.321432320000/main”

device directory

Used for the dir and present method. E.g. “/10.4300AC220000” “/statistics”

device properties

Used to read, write. E.g. “/10.4300AC220000/temperature”

New value for a device property. Used by write.

OWFS is a suite of programs that allows easy access to Dallas Semiconductor's 1-wire bus and devices.  OWFS provides a consistent naming scheme, safe multplexing of 1-wire traffice, multiple methods of access and display, and network access.  The basic OWFS metaphor is a file-system, with the bus beinng the root directory, each device a subdirectory, and the the device properties (e.g. voltage, temperature, memory) a file.

1-wire is a protocol allowing simple connection of inexpensive devices.  Each device has a unique ID number (used in its OWFS address) and is individually addressable.  The bus itself is extremely simple — a data line and a ground. The data line also provides power.  1-wire devices come in a variety of packages — chips, commercial boxes, and iButtons (stainless steel cans).  1-wire devices have a variety of capabilities, from simple ID to complex voltage, temperature, current measurements, memory, and switch control.

Connection to the 1-wire bus is either done by bit-banging a digital pin on the processor, or by using a bus master — USB, serial, i2c, parallel.  The heavy-weight OWFS programs: owserver owfs owhttpd owftpd and the heavy-weight perl module OW all link in the full OWFS library and can connect directly to the bus master(s) and/or to owserver.

OWNet is a light-weight module. It connects only to an owserver, does not link in the OWFS library, and should be more portable..

OWNet can be used in either a classical (non-object-oriented) manner, or with objects.  The object stored the ip address of the owserver and a network socket to communicate.  OWNet will use persistent tcp connections for the object form — potentially a performance boost over a slow network.

owserver is a separate process that must be accessible on the network. It allows multiple clients, and can connect to many physical 1-wire adapters and 1-wire devices. It's address must be discoverable — either set on the command line, or at it's default location, or by using Bonjour (zeroconf) service discovery.

An example owserver invocation for a serial adapter and explicitly chooses the default port:

 owserver -d /dev/ttyS0 -p 4304

 use OWNet ;

 # Create owserver object
 my $owserver = OWNet->new('localhost:4304 -v -F') ; #default location, verbose errors, Fahrenheit degrees
 # my $owserver = OWNet->new() ; #simpler, again default location, no error messages, default Celsius

 #print directory
 print $owserver->dir('/') ;

 #print temperature from known device (DS18S20,  ID: 10.13224366A280)
 print "Temperature: ".$owserver->read('/uncached/10.13224366A280/temperature') ;

 # Now for some fun -- a tree of everything:
 sub Tree($$) {
   my $ow = shift ;
   my $path = shift ;

   print "$path\t" ;

   # first try to read
   my $value = $ow->read($path) ;
   if ( defined($value) ) {
     print "$value\n";
     return ;
   }

   # not readable, try as directory
   my $dirstring = $ow->dir($path) ;
   if ( defined($dirstring) ) {
     print "<directory>\n" ;
     my @dir = split /,/ ,  $ow->dir($path) ;
     foreach (@dir) {
        Tree($ow,$_) ;
     }
     return ;
   }

   # can't read, not directory
   print "<write-only>\n" ;
   return ;
 }

 Tree( $owserver, '/' ) ;

ADDR

literal sting for the IP address, in dotted-quad or host format. This property is also used to indicate a substantiated object.

PORT

string for the port number (or service name). Service name must be specified as :owserver or the like.

SG

Flag sent to server, and returned, that encodes temperature scale and display format. Persistence is also encoded in this word in the actual tcp message, but kept separately in the object.

VERBOSE

Print error messages? Set by “-v” in object invocation.

SLASH

Add “/” to the end of directory entries. Set by “-slash” in object invocation.

SOCK

Socket address (object) for communication. Stays defined for persistent connections, else deleted between calls.

PERSIST

State of socket connection (persistent means the same socket is used which speeds network communication).

VER

owprotocol version number (currently 0)

_self

Takes either the implicit object reference (if called on an object) or the ip address in non-object format.  In either case a socket is created, the persistence bit is properly set, and the address parsed.  Returns the object reference, or undef on error.  Called by each external method (read,write,dir) on the first parameter.

_new

Takes command line invocation parameters (for an object or not) and properly parses and sets up the properties in a hash array.

_Sock

Socket processing, including tests for persistence and opening. If no host is specified, localhost (127.0.0.1) is used. If no port is specified, uses the IANA allocated well known port (4304) for owserver. First looks in /etc/services, then just tries 4304.

_ToServer

Sends a message to owserver. Formats in owserver protocol. If a persistent socket fails, retries after new socket created.

_FromServerBinaryParse

Reads a specified length from server

_FromServer

Reads whole packet from server, using _FromServerBinaryParse (first for header, then payload). Discards ping packets silently.

_BonjourLookup

Uses the mDNS service discovery protocol to find an available owserver. Employs NET::Rendezvous (an earlier name or Apple's Bonjour) This module is loaded only if available. (Uses the method of http://sial.org/blog/2006/12/optional_perl_module_loading.html)