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.
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 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).
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 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.
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
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) 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 EDS0066 (3) EDS0068 (3)
Moisture¶
EEEF (3) DS2438 (3)
AVAILABILITY¶
http://www.owfs.org
AUTHOR¶
Paul Alfille (paul.alfille@gmail.com)