--- name: "LCD" section: "3" platform: "linux" package: "owfs-doc" version: "3.2p4+dfsg1-6" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/LCD" --- # LCD(3) LCD controller ## 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 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 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 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 fundamental 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 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) InfernoEmbedded (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)