--- name: "DS2408" section: "3" platform: "linux" package: "owfs-doc" version: "3.2p4+dfsg1-6" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/DS2408" --- # DS2408(3) 1-Wire 8 Channel Addressable Switch ## NAME **DS2408** - 1-Wire 8 Channel Addressable Switch ## SYNOPSIS 8 port switch **29** \[.\]XXXXXXXXXXXX\[XX\]\[/\[ **latch.\[0-7\|ALL\|BYTE\]** \| **LCD\_M/\[clear\|home\|screen\|message\]** \| **LCD\_H/\[clear\|home\|yxscreen\|screen\|message\|onoff\]** \| **LCD\_H/redefchar.\[0-7\|ALL\] LCD\_H/redefchar\_hex.\[0-7\|ALL\]** \| **PIO.\[0-7\|ALL\|BYTE\]** \| **power** \| **sensed.\[0-7\|ALL\|BYTE\]** \| **strobe** \| **por** \| **set\_alarm** \| **out\_of\_testmode** \| **address** \| **crc8** \| **id** \| **locator** \| **r\_address** \| **r\_id** \| **r\_locator** \| **type** \]\] ## FAMILY CODE *29* ## SPECIAL PROPERTIES ### latch.0 ... latch.7 latch.ALL latch.BYTE *read-write, binary*\ The 8 pins (PIO) latch a bit when their state changes, either externally, or through a write to the pin. \ Reading the *latch* property indicates that the latch has been set.\ Writing "true" (non-zero) to ANY *latch* will reset them all. (This is the hardware design).\ *ALL* is all *latch* states, accessed simultaneously, comma separated.\ *BYTE* references all channels simultaneously as a single byte. Channel 0 is bit 0. ### PIO.0 ... PIO.7 PIO.ALL PIO.BYTE *read-write, yes-no*\ State of the open-drain output ( *PIO* ) pin. 0 = non-conducting (off), 1 = conducting (on).\ Writing zero will turn off the switch, non-zero will turn on the switch. Reading the *PIO* state will return the switch setting. To determine the actual logic level at the switch, refer to the *sensed.0 ... sensed.7 sensed.ALL sensed.BYTE* property.\ *ALL* references all channels simultaneously, comma separated.\ *BYTE* references all channels simultaneously as a single byte. Channel 0 is bit 0. ### power *read-only, yes-no*\ Is the *DS2408* powered parasitically (0) or separately on the Vcc pin (1)? ### sensed.0 ... sensed.7 sensed.ALL *read-only, yes-no*\ Logic level at the *PIO* pin. 0 = ground. 1 = high (~2.4V - 5V ). Really makes sense only if the *PIO* state is set to zero (off), else will read zero.\ *ALL* references all channels simultaneously, comma separated.\ *BYTE* references all channels simultaneously as a single byte. Channel 0 is bit 0. ### strobe *read-write, yes-no*\ RSTZ Pin Mode Control. Configures RSTZ as either RST input or STRB output: - *0* configured as RST input (default) - *1* configured as STRB output ### por *read-write, yes-no*\ Specifies whether the device has performed power-on reset. This bit can only be cleared to 0 under software control. As long as this bit is 1 the device will always respond to a conditional search. ### out\_of\_testmode *write-only, yes-no*\ Write "1" to this property to make sure the device has been properly initialized on startup. The datasheet says that under some conditions the startup (power-up) will leave the device in the "testmode" state. Any problems with "Channel Access Write" will trigger this property automatically, but this property makes explicit initialization possible as well. ### set\_alarm *read-write, integer unsigned (0-333333333)*\ A number consisting of 9 digits XYYYYYYYY, where: - X select source and logical term \ *0* PIO OR \ *1* latch OR \ *2* PIO AND \ *3* latch AND - Y select channel and polarity\ *0* Unselected (LOW) \ *1* Unselected (HIGH) \ *2* Selected LOW \ *3* Selected HIGH All digits will be truncated to the 0-3 range. Leading zeroes are optional. Low-order digit is channel 0. Example: - 100000033 Responds on Conditional Search when latch.1 or latch.0 are set to 1. - 222000000 Responds on Conditional Search when sensed.7 and sensed.6 are set to 0. - 000000000 (0) Never responds to Conditional Search. ## LCD\_H LCD SCREEN PROPERITES This mode uses the *DS2408* attached to a Hitachi HD44780 LCD controller in 4-bit mode. See *DATASHEET* for published details. Based on a commercial product from *HobbyBoards* by Erik Vickery. ### LCD\_H/clear *write-only, yes-no*\ This will *clear* the screen and place the cursor at the start. ### LCD\_H/home *write-only, yes-no*\ Positions the cursor in the *home* (upper left) position, but leaves the current text intact. ### LCD\_H/screen *write-only, ascii text*\ Writes to the LCD *screen* at the current position. ### LCD\_H/screenyc *write-only, ascii text*\ Writes to an LCD screen at a specified location. The controller doesn't know the true LCD dimensions, but typical selections are: 2x16 2x20 4x16 and 4x20. - Y (row) range 1 to 2 (or 4) - X (column) range 1 to 16 (or 20) There are two formats allowed for the *screenyx* text, either ascii (readable text) or a binary form. - 2 binary bytes The two first characters of the passed string have the line and row: e.g. "\\x02\\x04string" perl string writes "string" at line 2 column 4. - ascii 2,12: Two numbers giving line and row: Separate with a comma and end with a colon e.g. "2,4:string" writes "string" at line 2 column 4. - ascii 12: Single column number on the (default) first line: End with a colon e.g. "12:string" writes "string" at line 1 column 12. The positions are 1-based (i.e. the first position is 1,1). ### LCD\_H/onoff *write-only, unsigned*\ Sets several screen display functions. The selected choices should be added together. - 4 Display on - 2 Cursor on - 1 Cursor blinking ### LCD\_H/message *write-only, ascii text*\ Writes a *message* to the LCD screen after clearing the screen first. This is the easiest way to display a message. ### LCD\_H/redefchar.0-7\|ALL *write-only, binary*\ Redefines one of 8 user-designed character glyphs for the LCD screen (5x8 pixels). Each byte defines a horizontal line top to bottom. All 5 pixels corresponds to 0x1F and a blank line is 0x00. Format is 8 binary bytes. ### LCD\_H/redefchar\_hex.0-7\|ALL *write-only, ascii*\ Redefines one of 8 user-designed character glyphs for the LCD screen (5x8 pixels). Each byte defines a horizontal line top to bottom. All 5 pixels corresponds to 0x1F and a blank line is 0x00. Format is 8 hexadecimal bytes (16 characters). ## LCD\_M LCD SCREEN PROPERITES This mode uses the *DS2408* attached to a Hitachi HD44780 LCD controller in 8-bit mode. See *DATASHEET* for published details. Based on a design from Maxim and a commercial product from *AAG.* ### LCD\_M/clear *write-only, yes-no*\ This will *clear* the screen and place the cursor at the start. ### LCD\_M/home *write-only, yes-no*\ Positions the cursor in the *home* (upper left) position, but leaves the current text intact. ### LCD\_M/screen *write-only, ascii text*\ Writes to the LCD *screen* at the current position. ### LCD\_M/screenyc *write-only, ascii text*\ Writes to an LCD screen at a specified location. The controller doesn't know the true LCD dimensions, but typical selections are: 2x16 2x20 4x16 and 4x20. - Y (row) range 1 to 2 (or 4) - X (column) range 1 to 16 (or 20) There are two formats allowed for the *screenyx* text, either ascii (readable text) or a binary form. - 2 binary bytes The two first characters of the passed string have the line and row: e.g. "\\x02\\x04string" perl string writes "string" at line 2 column 4. - ascii 2,12: Two numbers giving line and row: Separate with a comma and end with a colon e.g. "2,4:string" writes "string" at line 2 column 4. - ascii 12: Single column number on the (default) first line: End with a colon e.g. "12:string" writes "string" at line 1 column 12. The positions are 1-based (i.e. the first position is 1,1). ### LCD\_M/onoff *write-only, unsigned*\ Sets several screen display functions. The selected choices should be added together. - 4 Display on - 2 Cursor on - 1 Cursor blinking ### LCD\_M/message *write-only, ascii text*\ Writes a *message* to the LCD screen after clearing the screen first. This is the easiest way to display a message. ## 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 Use the *set\_alarm* property to set the alarm triggering criteria. ## 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. ### DS2408 The **DS2408 (3)** allows control of other devices, like LEDs and relays. It extends the **DS2406** to 8 channels and includes memory.\ Alternative switches include the **DS2406, DS2407** and even **DS2450** ## 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/DS2408.pdf\ http://www.hobby-boards.com/catalog/howto\_lcd\_driver.php\ http://www.maxim-ic.com/appnotes.cfm/appnote\_number/3286 ## 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)