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DS2755(3)                    One-Wire File System                    DS2755(3)


DS2755, DS2756 - Multichemistry Battery Fuel Gauge


Temperature Voltage, Current, Memory, and Switch. 35 [.]XXXXXXXXXXXX[XX][/[ alarm_set/[volthigh|voltlow|temphigh|templow] | lock.[0-2|ALL] | memory | pages/page.[0-2|ALL] | PIO | sensed | temperature | vbias | vis | volt | volthours | defaultpmod | pie0 | pie1 | rnaop | ios | uben | ovd | pmod | por | uven | See the file man3/standard_mini.3so. ]] Thermocouple 35 [.]XXXXXXXXXXXX[XX][/[ temperature | typeX/range_low | typeX/range_high | typeX/temperature




alarm_set/templow alarm_set/temphigh read-write, integer High and low alarm settings for temperature alarm_set/voltlow alarm_set/volthigh read-write, floating point High and low alarm settings for volts lock.[0-2|ALL] read-write, yes-no Lock any of the three eprom pages to prevent further writes. Apparently setting lock is permanent. 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. pages/pages.[0-2|ALL] read-write, binary Three 32 byte areas of memory for user application. The lock property can prevent further alteration. NOTE that the page property is different from the common OWFS implementation in that all of memory is not accessible. 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. temperature read-only, floating point Temperature read by the chip at high resolution (~13 bits). Units are selected from the invoking command line. See owfs(1) or owhttpd(1) for choices. Default is Celsius. Conversion is continuous. vbias read-write, floating point Fixed offset applied to each vis measurement. Used for the volthours value. Units are in Volts. Range -2.0mV to 2.0mV 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. volt read-only, floating point Voltage read at the voltage sensor;. This is separate from the vis voltage that is used for current measurement. Units are Volts Range is between 0 and 4.75V volthours read-write, floating point Integral of vis - vbias over time. Units are in volthours


typeX/ directory Thermocouple circuit using the DS2755 to read the Seebeck voltage and the reference temperature. Since the type interpretation of the values read depends on the type of thermocouple, the correct directory must be chosen. Supported thermocouple types include types B, E, J, K, N, R, S and T. typeX/range_low typeX/ranges_high read-only, flaoting point The lower and upper temperature supported by this thermocouple (at least by the conversion routines). In the globally chosen temperature units. typeX/temperature read-only, floating point Thermocouple temperature. Requires a voltage and temperature conversion. Returned in globally chosen temperature units. Note: there are two types of temperature measurements possible. The temperature value in the main device directory is the reference temperature read at the chip. The typeX/temperature value is at the thermocouple junction, probably remote from the chip.


pmod por uven pie0 pie1 ios uben ovd rnaop varies, 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. defaultpmod read-write, yes-no Default power-on state for the corresponding properties.


See the file man3/standard.3so.


Temperature and voltage.


See the file man3/description.3so. DS2755 DS2756 The DS2755 (3) and DS2756 (3) are battery charging controllers similar to the DS2751 (3) except no internal resistor option and a larger EEPROM memory. The DS2756 (3) adds suspend modes ( pie0 pie1 ) to the DS2755 (3) A number of interesting devices can be built with the DS2755 (3) and DS2756 (3) including thermocouples. Support for thermocouples in built into the software, using the embedded thermister as the cold junction temperature.


See the file man3/addressing.3so.


http://pdfserv.maxim-ic.com/en/ds/DS2755.pdf http://pdfserv.maxim-ic.com/en/ds/DS2756.pdf


See the file man3/seealso.3so.




Paul Alfille (paul.alfille@gmail.com) OWFS Manpage 2003 DS2755(3)

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