DS2450(3) One-Wire File System DS2450(3) # [NAME](#NAME) **DS2450** - Quad A/D Converter # [SYNOPSIS](#SYNOPSIS) ## [Voltage * 4 and Memory.](#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][/[ See the file man3/standard\_mini.3so. ]] ## [CO2 sensor](#CO2_sensor) **20** \[.]XXXXXXXXXXXX\[XX]\[/\[ **CO2/ppm** | **CO2/power** | **CO2/status** ] # [FAMILY CODE](#FAMILY_CODE) *20* # [SPECIAL PROPERTIES](#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](#voltage) 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](#manual) The flag can be set by a direct write to *alarm/high* or *alarm/low* ## [memory](#memory) *read-write, binary* 32 bytes of data. Much has special implications. See the datasheet. ## [pages/page.0 ... pages/page.3 pages/page.ALL](#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](#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](#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/high.A_..._set_alarm/high.D_set_alarm/high.ALL) ## [set\_alarm/low.A ... set\_alarm/low.D set\_alarm/low.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/volthigh.A_..._set_alarm/volthigh.D_set_alarm/volthigh.ALL) ## [set\_alarm/volt2high.A ... set\_alarm/volt2high.D set\_alarm/volt2high.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/voltlow.A_..._set_alarm/voltlow.D_set_alarm/voltlow.ALL) ## [set\_alarm/volt2low.A ... set\_alarm/volt2low.D set\_alarm/volt2low.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](#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](#volt.A_..._volt.D_volt.ALL) ## [volt2.A ... volt2.D volt2.ALL](#volt2.A_..._volt2.D_volt2.ALL) ## [8bit/volt.A ... 8bit/volt.D 8bit/volt.ALL](#8bit/volt.A_..._8bit/volt.D_8bit/volt.ALL) ## [8bit/volt2.A ... 8bit/volt2.D 8bit/volt2.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](#latestvolt.A_..._latestvolt.D_latestvolt.ALL) ## [latestvolt2.A ... latestvolt2.D latestvolt2.ALL](#latestvolt2.A_..._latestvolt2.D_latestvolt2.ALL) ## [8bit/latestvolt.A ... 8bit/latestvolt.D 8bit/latestvolt.ALL](#8bit/latestvolt.A_..._8bit/latestvolt.D_8bit/latestvolt.ALL) ## [8bit/latestvolt2.A ... 8bit/latestvolt2.D 8bit/latestvolt2.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](#CO2_%28Carbon_Dioxide%29_SENSOR_PROPERTIES) The CO2 sensor is a device constructed from a SenseAir K30 and a *DS2450* ## [CO2/power](#CO2/power) *read-only, floating point* Supply voltage to the CO2 sensor (should be around 5V) ## [CO2/ppm](#CO2/ppm) *read-only, unsigned* CO2 level in ppm (parts per million). Range 0-5000. ## [CO2/status](#CO2/status) *read-only, yes-no* Is the internal voltage correct (around 3.2V)? # [STANDARD PROPERTIES](#STANDARD_PROPERTIES) See the file man3/standard.3so. # [ALARMS](#ALARMS) None. # [DESCRIPTION](#DESCRIPTION) See the file man3/description.3so. ## [DS2450](#DS2450) The [**DS2450 (3)**](/man/os/owfs/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](#ADDRESSING) See the file man3/addressing.3so. # [DATASHEET](#DATASHEET) [DS2450](#DS2450~2) http://pdfserv.maxim-ic.com/en/ds/DS2450.pdf [CO2 sensor](#CO2) http://www.senseair.se/Datablad/k30%20.pdf [CO2 device](#CO2~2) https://www.m.nu/co2meter-version-2-p-259.html?language=en # [SEE ALSO](#SEE_ALSO) See the file man3/seealso.3so. # [AVAILABILITY](#AVAILABILITY) http://www.owfs.org # [AUTHOR](#AUTHOR) Paul Alfille (paul.alfille@gmail.com) 2003 OWFS Manpage --- Document: DS2450(3) from owfs 3.2.4-r9 (Chainguard OS) Source: https://github.com/owfs/owfs