--- name: "DS2450" section: "3" platform: "linux" package: "owfs-doc" version: "3.2p4+dfsg1-6" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/DS2450" --- # DS2450(3) Quad A/D Converter ## NAME **DS2450** - Quad A/D Converter ## SYNOPSIS ### Voltage \* 4 and Memory. **20** \[.\]XXXXXXXXXXXX\[XX\]\[/\[ **PIO.\[A-D\|ALL\]** \| **volt.\[A-D\|ALL\]** \| **volt2.\[A-D\|ALL\]** \| **latestvolt.\[A-D\|ALL\]** \| **latestvolt2.\[A-D\|ALL\]** \]\] **20** \[.\]XXXXXXXXXXXX\[XX\]\[/\[ **8bit/volt.\[A-D\|ALL\]** \| **8bit/volt2.\[A-D\|ALL\]** \| **8bit/latestvolt.\[A-D\|ALL\]** \| **8bit/latestvolt2.\[A-D\|ALL\]** \]\] **20** \[.\]XXXXXXXXXXXX\[XX\]\[/\[ **memory** \| **pages/page.\[0-3\|ALL\]** \| **power** \] **20** \[.\]XXXXXXXXXXXX\[XX\]\[/\[ **alarm/high.\[A-D\|ALL\]** \| **alarm/low.\[A-D\|ALL\]** \| **set\_alarm/high.\[A-D\|ALL\]** \| **set\_alarm/low.\[A-D\|ALL\]** \| **set\_alarm/unset** \| **set\_alarm/volthigh.\[A-D\|ALL\]** \| **set\_alarm/volt2high.\[A-D\|ALL\]** \| **set\_alarm/voltlow.\[A-D\|ALL\]** \| **set\_alarm/volt2low.\[A-D\|ALL\]** \] **20** \[.\]XXXXXXXXXXXX\[XX\]\[/\[ **address** \| **crc8** \| **id** \| **locator** \| **r\_address** \| **r\_id** \| **r\_locator** \| **type** \]\] ### CO2 sensor **20** \[.\]XXXXXXXXXXXX\[XX\]\[/\[ **CO2/ppm** \| **CO2/power** \| **CO2/status** \] ## FAMILY CODE *20* ## SPECIAL PROPERTIES ### alarm/high.A ... alarm/high.D alarm.high.ALL ### alarm/high.A ... alarm/high.D alarm.high.ALL *read-write, binary*\ The alarm state of the voltage channel. The alarm state is set one of two ways: - voltage conversion Whenever the *DS2450* measures a voltage on a channel, that voltage is compared to the high and low limits *set\_alarm/volthigh* and/or *set\_alarm/voltlow* and if the alarm is enabled *set\_alarm/high* and/or *set\_alarm/low* the corresponding flag is set in *alarm/high* and/or *alarm/low* - manual set The flag can be set by a direct write to *alarm/high* or *alarm/low* ### memory *read-write, binary*\ 32 bytes of data. Much has special implications. See the datasheet. ### pages/page.0 ... pages/page.3 pages/page.ALL *read-write, binary*\ Memory is split into 4 pages of 8 bytes each. Mostly for reading and setting device properties. See the datasheet for details.\ *ALL* is an aggregate of the pages. Each page is accessed sequentially. ### PIO.A ... PIO.D PIO.ALL *read-write, yes-no*\ Pins used for digital control. 1 turns the switch on (conducting). 0 turns the switch off (non-conducting).\ Control is specifically enabled. Reading *volt* will turn off this control.\ *ALL* is an aggregate of the voltages. Readings are made separately. ### power *read-write, yes-no*\ Configure whether the *DS2450* is externally powered (as opposed to parasitically powered from the data line).\ If configured as powered, the A/D coverter will be set to continuous sampling, and the bus will be released during a single conversion allowing other devices to communicate.\ Setting this to 1 when no power is applied to the chip's Vcc will result in wrong voltage readouts. Setting this to 0 when power is applied to the chip's Vcc allows a simultaneous conversion trigger on all *DS2450* on a bus. The (always safe) default is 0. ### set\_alarm/high.A ... set\_alarm/high.D set\_alarm/high.ALL ### set\_alarm/low.A ... set\_alarm/low.D set\_alarm/low.ALL *read-write, yes-no*\ Enabled status of the voltage threshold. 1 is on. 0 is off. ### set\_alarm/volthigh.A ... set\_alarm/volthigh.D set\_alarm/volthigh.ALL ### set\_alarm/volt2high.A ... set\_alarm/volt2high.D set\_alarm/volt2high.ALL ### set\_alarm/voltlow.A ... set\_alarm/voltlow.D set\_alarm/voltlow.ALL ### set\_alarm/volt2low.A ... set\_alarm/volt2low.D set\_alarm/volt2low.ALL *read-write, floating point*\ The upper or lower limit for the voltage measured before triggering an alarm.\ Note that the alarm must be enabled *alarm/high* or *alarm.low* and an actual reading must be requested *volt* for the alarm state to actually be set. The alarm state can be sensed at *alarm/high* and *alarm/low* ### set\_alarm/unset *read-write, yes-no*\ Status of the power-on-reset (POR) flag.\ The POR is set when the *DS2450* is first powered up, and will match the alarm state until explicitly cleared. (By writing 0 to it).\ The purpose of the POR is to alert the user that the chip is not yet fully configured, especially alarm thresholds and enabling. ### volt.A ... volt.D volt.ALL ### volt2.A ... volt2.D volt2.ALL ### 8bit/volt.A ... 8bit/volt.D 8bit/volt.ALL ### 8bit/volt2.A ... 8bit/volt2.D 8bit/volt2.ALL *read-only, floating point*\ Reading one of these nodes triggers a conversion on the specified voltage input(s) with the selected resolution (16 or 8 bit) and returns the sampled voltage(s) with the selected scaling (0 - 5.10V or 0 - 2.55V). The conversion time is about 1.4ms per input for 16-bit and 0.8ms per input for 8-bit. The output feature ( *PIO* ) is disabled by reading the corresponding node.\ *ALL* is an aggregate of the voltages. Sampling is controlled by the chip and done in the order A, B, C, D, one after another. ### latestvolt.A ... latestvolt.D latestvolt.ALL ### latestvolt2.A ... latestvolt2.D latestvolt2.ALL ### 8bit/latestvolt.A ... 8bit/latestvolt.D 8bit/latestvolt.ALL ### 8bit/latestvolt2.A ... 8bit/latestvolt2.D 8bit/latestvolt2.ALL *read-only, floating point*\ Returns previously measured voltage on the specified input(s) with the selected scaling (0 - 5.10V or 0 - 2.55V). Resolution and scaling are set by sampling a voltage, not here; the correct latestvolt nodes have to be read to make the result meaningful.\ *ALL* is an aggregate of the voltages and returns all voltage values from the chip.\ Reading these nodes will never trigger a voltage conversion. Intended for use in conjunction with **/simultaneous/voltage.** ## CO2 (Carbon Dioxide) SENSOR PROPERTIES The CO2 sensor is a device constructed from a SenseAir K30 and a *DS2450* ### CO2/power *read-only, floating point*\ Supply voltage to the CO2 sensor (should be around 5V) ### CO2/ppm *read-only, unsigned*\ CO2 level in ppm (parts per million). Range 0-5000. ### CO2/status *read-only, yes-no*\ Is the internal voltage correct (around 3.2V)? ## 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. ## 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. ### DS2450 The **DS2450 (3)** is a (supposedly) high resolution A/D converter with 4 channels. Actual resolutin is reporterd to be 8 bits. The channels can also function as switches. Voltage sensing (with temperature and current, but sometimes restricted voltrage ranges) can also be obtained with the **DS2436** , **DS2438** and **DS276x** ## 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 - DS2450 http://pdfserv.maxim-ic.com/en/ds/DS2450.pdf - CO2 sensor http://www.senseair.se/Datablad/k30%20.pdf - CO2 device https://www.m.nu/co2meter-version-2-p-259.html?language=en ## 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)