| DS2740(3) | One-Wire File System | DS2740(3) |
NAME
DS2740 - High-Precision Coulomb Counter
SYNOPSIS
Voltage and Switch
36 [.]XXXXXXXXXXXX[XX][/[ memory | PIO |
sensed | vis | vis_B | volthours |
smod |
See the file man3/standard_mini.3so.
]]
FAMILY CODE
36
SPECIAL PROPERTIES
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
OBSCURE PROPERTIES
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.
STANDARD PROPERTIES
See the file man3/standard.3so.
ALARMS
None.
DESCRIPTION
See the file man3/description.3so.
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.
ADDRESSING
See the file man3/addressing.3so.
DATASHEET
http://pdfserv.maxim-ic.com/en/ds/DS2740.pdf
SEE ALSO
See the file man3/seealso.3so.
AVAILABILITY
http://www.owfs.org
AUTHOR
Paul Alfille (paul.alfille@gmail.com)
| 2003 | OWFS Manpage |