SNOA993A June   2018  – July 2021 LDC2112 , LDC2114 , LDC3114 , LDC3114-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2Scan Rate and Sampling Interval
    1. 2.1 Low Power Mode and Normal Power Mode
    2. 2.2 Button Sequencing and Error Handling
  4. 3Data Polarity and Timeout
    1. 3.1 Button Timeout
  5. 4Internal Algorithms Overview
  6. 5Baseline Tracking
    1. 5.1 Baseline Increment
    2. 5.2 Baseline Tracking Reset
    3. 5.3 Button Actuation Time
    4. 5.4 BTPAUSE
    5. 5.5 Fast Tracking Factor
  7. 6Gain, Hysteresis, and Threshold
    1. 6.1 Threshold and Hysteresis
  8. 7Multi-Button Algorithms
    1. 7.1 Max Win
    2. 7.2 Anti-Common Mode
    3. 7.3 Anti-Twist Factor
    4. 7.4 Anti-Deform Factor
  9. 8Summary
  10. 9Revision History

3 Data Polarity and Timeout

The LDC211x and LDC3114 can detect positive or negative frequency shifts as button events. This is controlled per channel by the DPOLx setting, which adjusts the polarity of data processing. Figure 3-1 shows how this can be configured to support either inductive or capacitive sensing by the same device, or even a combination where some buttons operate as inductive sensors and the others operate as capacitive sensors. For a capacitive sensor, setting DPOLx to 0 inverts the sign of the internal data processing. This results in a signal which operates in the same sign as an inductive sensor, and so all other internal algorithms operate consistently.

GUID-7D204425-BC96-4BC9-8D8E-13ED1A518E8C-low.pngFigure 3-1 DPOLx functionality with Inductive and Capacitive Sensing