Ubuntu Manpage: DS2415, DS1904, DS2417 - 1-Wire Time Chip, RTC (real time clock) iButton, 1-Wire Time Chip

NAME

       DS2415, DS1904, DS2417 - 1-Wire Time Chip, RTC (real time clock) iButton, 1-Wire Time Chip
       with Interrupt

SYNOPSIS

       Real time clock.
       24 [.]XXXXXXXXXXXX[XX][/[ date | flags | running | udate | address | crc8 | id | locator |
       r_address | r_id | r_locator | type ]]

       Clock with interrupts
       27  [.]XXXXXXXXXXXX[XX][/[  date | enable | interval | itime | running | udate | address |
       crc8 | id | locator | r_address | r_id | r_locator | type ]]

FAMILY CODE

       24     DS2415 DS1904

       27     DS2417

SPECIAL PROPERTIES

   date
       read-write, ascii
       26 character date representation of the counter value. Increments once  per  second  while
       running
       Setting date to a null string will put the current system time.
       Accepted date formats are:
         Sat[urday] March 12 12:23:59 2001
         Apr[il] 4 9:34:56 2002
         3/23/04 23:34:57
         current locale setting (your system's format)

   enable
       read-write, yes-no
       State of the timer interrupt. 0=off 1=running.

   interval
       read-write, unsigned integer
       Interval   between  timer  interrupts.  Values:  0-7.  See  table  under  DESCRIPTION  for
       interpretation.  itime will reflect the interval chosen.

   itime
       read-write, unsigned integer
       Interval between timer interrupts. Value in  seconds.  See  table  under  DESCRIPTION  for
       interpretation and acceptable values.  interval will reflect the itime chosen.

   flags
       read-write, unsigned integer
       General use data. 4 bits (0-15 accepted values).

   running
       read-write, yes-no
       State of the clock. 0=off 1=running.

   udate
       read-write, unsigned integer
       Time represented as a number.  udate increments once per second, while running is on.
       Usually  set  to  unix  time standard: number of seconds since Jan 1, 1970. The date field
       will be the unix representation of udate and setting either will change the other.

STANDARD PROPERTIES

address
r_address
read-only, ascii
The entire 64-bit unique ID. Given as upper case hexadecimal digits (0-9A-F).
address starts with the family code
r address is the address in reverse order, which is often used in other applications and
labeling.

crc8
read-only, ascii
The 8-bit error correction portion. Uses cyclic redundancy check. Computed from the
preceding 56 bits of the unique ID number. Given as upper case hexadecimal digits (0-9A-
F).

family
read-only, ascii
The 8-bit family code. Unique to each type of device. Given as upper case hexadecimal
digits (0-9A-F).

id
r_id
read-only, ascii
The 48-bit middle portion of the unique ID number. Does not include the family code or
CRC. Given as upper case hexadecimal digits (0-9A-F).
r id is the id in reverse order, which is often used in other applications and labeling.

locator
r_locator
read-only, ascii
Uses an extension of the 1-wire design from iButtonLink company that associated 1-wire
physical connections with a unique 1-wire code. If the connection is behind a Link Locator
the locator will show a unique 8-byte number (16 character hexadecimal) starting with
family code FE.
If no Link Locator is between the device and the master, the locator field will be all FF.
r locator is the locator in reverse order.

present (DEPRECATED)
read-only, yes-no
Is the device currently present on the 1-wire bus?

type
read-only, ascii
Part name assigned by Dallas Semi. E.g. DS2401 Alternative packaging (iButton vs chip)
will not be distiguished.

ALARMS

       None implemented.

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 principle 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.

DS2415 DS1904
The DS2415 (3) and DS1904 (3) are simple clocks that can be read on the 1-wire bus. They
can also be used the time an event, for remote confirmation.

DS2417
The DS2417 has the same clock function, but also includes a programmable interval
interrupt. Values Allowed are:
0 1sec
1 4sec
2 32s = .5m
3 6 = 1m
4 2048s = .5h
5 4096s = 1h
6 65536s = 18h
7 131072s = 36h

ADDRESSING

       All 1-wire devices are factory assigned a unique 64-bit address. This address  is  of  the
       form:

       Family Code
              8 bits

       Address
              48 bits

       CRC    8 bits

       Addressing under OWFS is in hexadecimal, of form:

              01.123456789ABC

       where 01 is an example 8-bit family code, and 12345678ABC is an example 48 bit address.

       The dot is optional, and the CRC code can included. If included, it must be correct.

DATASHEET

       http://pdfserv.maxim-ic.com/en/ds/DS2415.pdf
       http://pdfserv.maxim-ic.com/en/ds/DS1904.pdf
       http://pdfserv.maxim-ic.com/en/ds/DS2417.pdf

AVAILABILITY

       http://www.owfs.org

AUTHOR

       Paul Alfille (paul.alfille@gmail.com)