Ubuntu Manpage: LCD - LCD controller

Provided by: owfs-doc_3.1p1-2ubuntu1_all

NAME

       LCD - LCD controller

SYNOPSIS

       1-wire LCD controller by Louis Swart

       FF   [.]XXXXXXXXXXXX[XX][/[   backlight  |  counters.[0-3|ALL]  |  cumulative.[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 cumulative counter
can have any value written, which allows preservation of counts accross 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 determined 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.

screen16 screen20 screen40
write-only,ascii
Write text to the LCD screen. Assumes 16/20/40 char width. (Cannot be determined 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 hexidecimal 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 hexidecimal digits (0-9A-
F).

family
read-only, ascii
The 8-bit family code. Unique to each type of device. Given as upper case hexidecimal
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 hexidecimal 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 hexidecimal) 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.

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 address is of the
       form:

       Family Code
              8 bits

       Address
              48 bits

       CRC    8 bits

       Addressing under OWFS is in hexidecimal, 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

AVAILABILITY

       http://www.owfs.org

AUTHOR

       Paul Alfille (paul.alfille@gmail.com)