DS2437(3)

NAME
DS2437 - Smart Battery Monitor

SYNOPSIS
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 | ]]

FAMILY CODE

1E

SPECIAL PROPERTIES

  date
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)

  current
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.

  disconnect/date
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.

  disconnect/udate
read-write, unsigned integer
Representation of disconnect/date as a number. See udate for details.

  endcharge/date
read-write, ascii
26 character date representation of the endcharge/udate value. Format is the same as the date property.

  endcharge/udate
read-write, unsigned integer
Representation of endcharge/date as a number. See udate for details.

  Ienable
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

  pages/page.0 ... pages/page.7 pages/page.ALL
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.

  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 takes ~20 msec.

  udate
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.

  VAD VDD
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.

STANDARD PROPERTIES

ALARMS
None.

DESCRIPTION

  DS2437
The DS2437 (3) is an obsolete version of the DS2438 (3) battery chip. Current sensing is availble, 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.

ADDRESSING

DATASHEET
http://pdfserv.maxim-ic.com/en/ds/DS2437.pdf
http://pdfserv.maxim-ic.com/en/an/humsensor.pdf

SEE ALSO

AVAILABILITY
http://www.owfs.org

AUTHOR
Paul Alfille (palfille@earthlink.net)