Datasheet X9312 (Intersil) - 3

X9312 INSTRUCTIONS AND PROGRAMMING MODE SELECTION
The INC, U/D and CS inputs control the movement of
CS INC U/D Mode
the wiper along the resistor array. With CS set LOW the device is selected and enabled to respond to the L H Wiper up U/D and INC inputs. HIGH to LOW transitions on INC will increment or decrement (depending on the state of L L Wiper down the U/D input) a seven bit counter. The output of this counter is decoded to select one of one hundred wiper H X Store wiper position positions along the resistive array. H X X Standby current The value of the counter is stored in nonvolatile memory whenever CS transitions HIGH while the INC L X No store, return to standby input is also HIGH. The system may select the X9312, move the wiper
SYMBOL TABLE
and deselect the device without having to store the latest wiper position in nonvolatile memory. After the wiper movement is performed as described above and
WAVEFORM INPUTS OUTPUTS
once the new position is reached, the system must Must be Will be keep INC LOW while taking CS HIGH. The new wiper steady steady position will be maintained until changed by the system or until a powerup/down cycle recalled the May change Will change from Low to from Low to previously stored data. High High May change Will change This procedure allows the system to always power-up from High to from High to to a preset value stored in nonvolatile memory; then Low Low during system operation minor adjustments could be Don’t Care: Changing: made. The adjustments might be based on user Changes State Not Allowed Known preference, system parameter changes due to N/A Center Line temperature drift, etc... is High Impedance The state of U/D may be changed while CS remains LOW. This allows the host system to enable the device and then move the wiper up and down until the proper trim is attained. 3 FN8176.0 March 15, 2005