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

6.1 Threshold and Hysteresis

After applying Gain Factorx, each channel Netx is compared to a fixed threshold of 128+Hysteresis. The Hysteresis value is set by the HYST register field. The Hysteresis value can be set from 0 to 60, in increments of 4. The HYST setting is common to all channels. A larger HYST setting improves the noise immunity and also increases the minimum button actuation time (when BTPAUSEx is not enabled). The GAINx and HYST settings effectively produce a variable Upper and Lower threshold, as seen in

GUID-9E454953-C581-483F-9695-0A06FFB5FCA4-low.pngFigure 6-2 Compare Thresholds based on HYST setting

The hysteresis and threshold operation is consistent with standard practice, in that:

  • If OUTx is asserted, OUTx deasserts if NETx < Lower Threshold
  • If OUTx is deasserted, OUTx asserts if NETx > Upper Threshold