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LCD(3)			      One-Wire File System			  LCD(3)

NAME
     LCD - LCD controller

SYNOPSIS
     1-wire LCD controller by Louis Swart

     FF   [.]XXXXXXXXXXXX[XX][/[   backlight   |  counters.[0-3|ALL]  |  cumula-
     tive.[0-3|ALL] |  branch.[0-1|ALL]  |  data  |  gpio.[0-3|ALL]  |	LCDon  |
     line16.[0-3|ALL]  | line20.[0-3|ALL] | line40.[0|1|ALL] | memory | register
     | screen16 | screen20 | screen40 | version | address | crc8 | id |  locator
     | r_address | r_id | r_locator | type ]]

FAMILY CODE
     FF

SPECIAL PROPERTIES
   backlight
     write-only,yes-no
     Write  a  non-zero  value	to turn on the LCD backlight. Write zero to turn
     off.

   counters[0-3,ALL]
     read-only,unsigned integer
     Read the number of times the gpio has been externally changed. If wired  to
     a	push  switch, will count twice per button press. The LCD firmware resets
     all the counter when any one is read. Use the ALL extension  to  read  them
     all, simultaneously, or use the cumulative property instead.
     ALL is an aggregate of the properties, comma separated. Read atomically.

   cumulative[0-3,ALL]
     read-write,unsigned integer
     Cumulative  sum of the counters property. To reset, write a zero. The cumu-
     lative counter can have any value written,  which	allows	preservation  of
     counts  across  program  restarts	if  the  value at program termination is
     stored.
     Reading cumulative will reset the counters  property.  All  the  cumulative
     counters  will be updated so that no counts will be lost. Reads of counters
     can be interspersed without losing cumulative accuracy.
     Note: cumulative requires the caching system be compiled into libow.
     ALL is an aggregate of the properties, comma separated.

   data
     read-write,unsigned int
     Contents of the LCD data byte (see datasheet). Not usually needed.

   LCDon
     write-only,yes-no
     Write a non-zero value to turn on the LCD screen  (also  clears).	Write  a
     zero to turn off.

   line16[0-3,ALL] line20[0-3,ALL] line40[0-1,ALL]
     write-only,ascii
     Write  text  to the LCD screen. Assumes 16/20/40 char width. (Cannot be de-
     termined from controller).
     ALL is an aggregate of the properties, comma  separated.  Each  is  set  in
     turn.

   memory
     read-write,binary
     112 bytes of on-board memory.

   register
     read-write,unsigned int
     Contents of the LCD register (see datasheet). Not usually needed.

   screen16 screen20 screen40
     write-only,ascii
     Write  text  to the LCD screen. Assumes 16/20/40 char width. (Cannot be de-
     termined from controller).

   version
     read-only,ascii
     Self-reported LCD controller version. 16 bytes.

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 ap-
     plications 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  asso-
     ciated  1-wire  physical connections with a unique 1-wire code. If the con-
     nection is behind a Link Locator the locator will show a unique 8-byte num-
     ber (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-connec-
     tor 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, temper-
     ature, 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 indi-
     vidually 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  con-
     sistent  interface. The goal is to provide an easy set of tools for a soft-
     ware 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  fundamental goal has been ease of use, flexibility and correct-
     ness rather than speed.

   LCD
     The LCD (3) controller is a microprocessor driven device that simulates the
     operation of 1-wire devices. It's creator has arbitrarily chosen the family
     code FF. The controller requires external power. Full details are available
     from the designer.
     The main draw of the LCD controller is as any easy way to provide output to
     users.

ADDRESSING
     All 1-wire devices are factory assigned a unique 64-bit address.  This  ad-
     dress 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
     Available from http://www.louisswart.co.za/1-Wire_index.html

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)  Infer-
     noEmbedded (3)

   Temperature
     DS1822  (3) DS1825 (3) DS1820 (3) DS18B20 (3) DS18S20 (3) DS1920 (3) DS1921
     (3) DS1821 (3) DS28EA00 (3) DS28E04 (3) EDS0064 (3) EDS0065 (3) EDS0066 (3)
     EDS0067 (3) EDS0068 (3) EDS0071 (3) EDS0072 (3) MAX31826 (3)

   Humidity
     DS1922 (3) DS2438 (3) EDS0065 (3) EDS0068 (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 (3) EDS0066 (3) EDS0068 (3)

   Moisture
     EEEF (3) DS2438 (3)

AVAILABILITY
     http://www.owfs.org

AUTHOR
     Paul Alfille (paul.alfille@gmail.com)

OWFS Manpage			      2003				  LCD(3)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=LCD&sektion=3&manpath=FreeBSD+Ports+15.1.quarterly>

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