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DS2450(3) One-Wire File System DS2450(3) 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 volt- age 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 con- trol. 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 para- sitically 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 al- lowing other devices to communicate. Setting this to 1 when no power is applied to the chip's Vcc will re- sult in wrong voltage readouts. Setting this to 0 when power is ap- plied 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 ac- tual 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 volt- age 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. Com- puted from the preceding 56 bits of the unique ID number. Given as up- per 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 applica- tions 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 manufac- tured 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 (humid- ity, 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 en- cryption 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, par- allel, 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 in- dividual 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 com- munication. Still the fundamental goal has been ease of use, flexibil- ity 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 cur- rent, 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) In- fernoEmbedded (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) OWFS Manpage 2003 DS2450(3)
NAME | SYNOPSIS | FAMILY CODE | SPECIAL PROPERTIES | CO2 (Carbon Dioxide) SENSOR PROPERTIES | STANDARD PROPERTIES | ALARMS | DESCRIPTION | ADDRESSING | DATASHEET | SEE ALSO | AVAILABILITY | AUTHOR
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