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DS2740 - High-Precision Coulomb Counter
Voltage and Switch 36 [.]XXXXXXXXXXXX[XX][/[ memory | PIO | sensed | vis | vis_B | volthours | smod | address | crc8 | id | locator | r_address | r_id | r_locator | type ]]
memory read-write, binary Access to the full 256 byte memory range. Much of this space is reserved or special use. User space is the page area. See the DATASHEET for a full memory map. PIO write-only, yes-no Controls the PIO pin allowing external switching. Writing "1" turns the PIO pin on (conducting). Writing "0" makes the pin non-conducting. The logical state of the voltage can be read with the sensed property. This will reflect the current voltage at the pin, not the value sent to PIO Note also that PIO will also be altered by the power-status of the DS2670 See the datasheet for details. sensed read-only, yes-no The logical voltage at the PIO pin. Useful only if the PIO property is set to "0" (non- conducting). Value will be 0 or 1 depending on the voltage threshold. vis read-only, floating point Current sensor reading (unknown external resistor). Measures the voltage gradient between the Vis pins. Units are in Volts The vis readings are integrated over time to provide the volthours property. The current reading is derived from vis assuming the internal 25 mOhm resistor is employed. There is no way to know this through software. vis_B read-only, floating point Current sensor reading (unknown external resistor). Measures the voltage gradient between the Vis pins. Units are in Volts The vis readings are integrated over time to provide the volthours property. The vis_B is from a different tuning of the DS2740 (3) chip with faster sampling and lower resolution. There is no way to know this through software. volthours read-write, floating point Integral of vis over time. Units are in volthours
smod read-write, yes-no Bit flags corresponding to various battery management functions of the chip. See the DATASHEET for details of the identically named entries. In general, writing "0" corresponds to a 0 bit value, and non-zero corresponds to a 1 bit value. Default power-on state for the corresponding properties.
address r_address read-only, ascii The entire 64-bit unique ID. Given as upper case hexidecimal 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 hexidecimal digits (0-9A- F). family read-only, ascii The 8-bit family code. Unique to each type of device. Given as upper case hexidecimal 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 hexidecimal 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 hexidecimal) 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.
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 fundemental goal has been ease of use, flexibility and correctness rather than speed. DS2740 The DS2740 (3) is a class of battery charging controllers. This chip measures voltage and volthours, and has a pin that can be used for control.
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 hexidecimal, 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.
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) 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 EDS0066 (3) EDS0068 (3) Moisture EEEF (3) DS2438 (3)
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