DS2740 − High-Precision Coulomb Counter
Voltage and Switch
36
[.]XXXXXXXXXXXX[XX][/[ memory | PIO |
sensed | vis | vis_B | volthours
|
smod |
]]
36
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.
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.
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.
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.
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.
read-write,
floating point
Integral of vis over time. Units are in
volthours
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.
None.
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.
http://pdfserv.maxim-ic.com/en/ds/DS2740.pdf
http://www.owfs.org
Paul Alfille ([email protected])