DS2437(3) One-Wire File System DS2437(3) NAME DS2437 - Smart Battery Monitor SYNOPSIS Temperature Voltages and Memory. 1E [.]XXXXXXXXXXXX[XX][/[ current | date | disconnect/date | discon- nect/udate | endcharge/date | endcharge/udate | Ienable | pages/page.[0-7|ALL] | temperature | udate | VAD | VDD | address | crc8 | id | locator | r_address | r_id | r_locator | type ]] FAMILY CODE 1E SPECIAL PROPERTIES date read-write, ascii 26 character date representation of the counter value. Increments once per second. Setting date to a null string will put the current system time. Accepted date formats are: Sat[urday] March 12 12:23:59 2001 Apr[il] 4 9:34:56 2002 3/23/04 23:34:57 current locale setting (your system's format) current read-only, integer Current reading. Actual current depends on Rsens resistor (see datasheet). The formula for current is I = current /(4096*Rsens) with units in Amps and Ohms. Current measurement will be temporarily enabled (see Ienable ) if not cur- rently enabled (pun intended) for this reading. disconnect/date read-write, ascii 26 character date representation of the disconnect/udate value. Time when the battery pack waws removed from the charger. Format is the same as the date property. disconnect/udate read-write, unsigned integer Representation of disconnect/date as a number. See udate for details. endcharge/date read-write, ascii 26 character date representation of the endcharge/udate value. Format is the same as the date property. endcharge/udate read-write, unsigned integer Representation of endcharge/date as a number. See udate for details. Ienable read-write, unsigned integer Status of current monitoring. When enabled, current sensing is performed 36.41 times/second. Values of Ienable are: 0 no current conversion 1 current conversion enabled 2 current conversion and accumulation 3 current conversion and accumulation with EEPROM backup pages/page.0 ... pages/page.7 pages/page.ALL read-write, binary Memory is split into 8 pages of 8 bytes each. Only the pages 3-7 are really available, and some of that appears to be reserved. See the datasheet for details. ALL is an aggregate of the pages. Each page is accessed sequentially. temperature read-only, floating point Temperature read by the chip at high resolution (~13 bits). Units are se- lected from the invoking command line. See owfs(1) or owhttpd(1) for choices. Default is Celsius. Conversion takes ~20 msec. udate read-write, unsigned integer Time represented as a number. udate increments once per second. Usually set to unix time standard: number of seconds since Jan 1, 1970. The date field will be the unix representation (ascii text) of udate and set- ting either will change the other. VAD VDD read-only, floating point Voltage read (~10 bits) at the one of the chip's two supply voltages. Range VDD= 2.4V to 10V, VAD=1.5 to 10V. 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 ap- plications 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 asso- ciated 1-wire physical connections with a unique 1-wire code. If the con- nection is behind a Link Locator the locator will show a unique 8-byte num- ber (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-connec- tor 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, temper- ature, 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 indi- vidually 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 con- sistent interface. The goal is to provide an easy set of tools for a soft- ware 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 correct- ness rather than speed. DS2437 The DS2437 (3) is an obsolete version of the DS2438 (3) battery chip. Cur- rent sensing is available, but not implemented. The major advantage com- pared to the DS2436 is that two voltages can be read, allowing correcting circuit nmeasurements to supply voltage and temperature. A better compari- son is the DS276x family of chips. ADDRESSING All 1-wire devices are factory assigned a unique 64-bit address. This ad- dress 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/DS2437.pdf http://pdfserv.maxim-ic.com/en/an/humsensor.pdf 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) Infer- noEmbedded (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 DS2437(3)
NAME | SYNOPSIS | FAMILY CODE | SPECIAL PROPERTIES | STANDARD PROPERTIES | ALARMS | DESCRIPTION | ADDRESSING | DATASHEET | SEE ALSO | AVAILABILITY | AUTHOR
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