DS2890(3)

NAME
DS2890 - 1-Wire Digital Potentiometer

SYNOPSIS
Variable resistance

2C [.]XXXXXXXXXXXX[XX][/[ chargepump | wiper | ]]

FAMILY CODE

2C

SPECIAL PROPERTIES

  chargepump
read-write, yes-no
State of the chargepump in the chip (0 = off 1 = on). Only available if external power is available (hence not in the TO-92 packaging) at pin Vdd.
When chargepump is on, the wiper resistance will range between Rh and Rl relatively linearly.
When chargepump is off, the wiper resistance (to ground) will range relatively linearly (to 100kOhms).

  wiper
read-write, unsigned integer
Value of the variable element, 0 to 255. The actual interpretation of wiper depands on the chargepump state, but in general 0 is low and 255 is high.

STANDARD PROPERTIES

ALARMS
The device condition that will cause individual DS2890s to participate in a Conditional Search is a wiper position located at the power-on default setting (00h). This feature enables the bus master to easily determine whether a potentiometer has gone through a power-on reset and needs to be re-configured with a required wiper position setting.

DESCRIPTION

  DS2890
The D2890 (3) allows variable resistance under 1-wire control. Possible uses are analog feedback mechanisms (sound pitch, light level).

Although there are provisions in the datasheet for different DS2890 configurations (non-linear wiper ranges, multiple wipers, different resistance scales) non are in production. To simplify implementation, this driver assumes the standard DS2890 design.

ADDRESSING

DATASHEET
http://pdfserv.maxim-ic.com/en/ds/DS2890.pdf

SEE ALSO

AVAILABILITY
http://www.owfs.org

AUTHOR
Paul Alfille (palfille@earthlink.net)