DS2437 − Smart Battery Monitor
Temperature Voltages and Memory.
1E [.]XXXXXXXXXXXX[XX][/[ current | date | disconnect/date | disconnect/udate | endcharge/date | endcharge/udate | Ienable | pages/page.[0-7|ALL] | temperature | udate | VAD | VDD | ]]
1E
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)
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 currently enabled (pun intended) for
this reading.
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.
read-write,
unsigned integer
Representation of disconnect/date as a number. See
udate for details.
read-write,
ascii
26 character date representation of the
endcharge/udate value. Format is the same as the
date property.
read-write,
unsigned integer
Representation of endcharge/date as a number. See
udate for details.
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 |
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.
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 takes ˜20
msec.
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 setting
either will change the other.
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.
None.
The DS2437 (3) is an obsolete version of the DS2438 (3) battery chip. Current sensing is available, but not implemented. The major advantage compared to the DS2436 is that two voltages can be read, allowing correcting circuit nmeasurements to supply voltage and temperature. A better comparison is the DS276x family of chips.
http://pdfserv.maxim-ic.com/en/ds/DS2437.pdf
http://pdfserv.maxim-ic.com/en/an/humsensor.pdf
http://www.owfs.org
Paul Alfille ([email protected])