Positive Recalibration Delay

If any key is found to have a significant drop in signal delta, (on the negative side), it is deemed to be an error condition. If this condition persists for more than the positive recalibration delay, i.e., qt_pos_recal_delay period, then an automatic recalibration is carried out.

A counter is incremented each time the sensor delta is equal to the positive recalibration threshold and stayed there for a specific number of acquisitions. When this counter reaches a preset limit (the PRD value) the sensor is finally recalibrated. If on any acquisition the delta is seen to be greater than the positive recalibration threshold level, the counter is cleared and the positive drifting is performed.

For example, if the PRD value is 10, then the delta has to drop below the recalibration threshold and stay there for 10 acquisitions in succession without going below the threshold level, before the sensor is declared to be recalibrated.

Setting

Variable name

Data Type

Unit

Min

Max

Typical

Positive Recalibration Delay

qt_pos_recal_delay

uint8_t

cycles

1

255

3