DragonFly On-Line Manual Pages
DS2890(3) One-Wire File System DS2890(3)
DS2890 - 1-Wire Digital Potentiometer
2C [.]XXXXXXXXXXXX[XX][/[ chargepump | wiper |
See the file man3/standard_mini.3so.
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
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).
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
See the file man3/standard.3so.
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.
See the file man3/description.3so.
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.
See the file man3/addressing.3so.
See the file man3/seealso.3so.
Paul Alfille (firstname.lastname@example.org)
OWFS Manpage 2003 DS2890(3)