AT42QT2120 Datasheet
Table Of Contents
- Features
- 1. Pinouts and Schematics
- 2. Overview
- 3. Wiring and Parts
- 4. I2C-compatible Communications (Comms Mode Only)
- 5. Setups
- 5.1 Introduction
- 5.2 Address 0: Chip ID
- 5.3 Address 1: Firmware Version
- 5.4 Address 2: Detection Status
- 5.5 Addresses 3 – 4: Key Status
- 5.6 Address 5: Slider Position
- 5.7 Address 6: Calibrate
- 5.8 Address 7: Reset
- 5.9 Address 8: Low Power (LP) Mode
- 5.10 Address 9 – 10: Toward Touch and Away from Touch Drift (TTD, ATD)
- 5.11 Address 11: Detection Integrator (DI)
- 5.12 Address 12: Touch Recal Delay (TRD)
- 5.13 Address 13: Drift Hold Time (DHT)
- 5.14 Address 14: Slider Options
- 5.15 Address 15: Charge Time
- 5.16 Address 16 – 27: Detect Threshold (DTHR)
- 5.17 Addresses 28 – 39: Key Control
- 5.18 Addresses 40 – 51: Pulse/Scale for Keys
- 5.19 Address 52 – 75: Key Signal
- 5.20 Address 76 – 99: Reference Data
- 6. Specifications
- Appendix A. I2C-compatible Operation
- Associated Documents
- Revision History
25
9634E–AT42–06/12
AT42QT2120
This feature is particularly useful in cases of high-density keypads where touching a key or
hovering a finger over the keypad would cause untouched keys to drift, and therefore create a
sensitivity shift, and ultimately inhibit any touch detection. It is expressed in 0.16 s increments.
DHT default value: 25
DHT range: 0 – 255
5.14 Address 14: Slider Options
EN: Setting this bit enables a Slider or Wheel to be configured. Only the first three channels (0,
1 and 2) can be used.
WHEEL: Setting this bit allows a wheel to be configured. If not set, and EN is enabled, it defaults
to a slider.
The range of both is from 0 – 255.
Figure 5-2. Slider/Wheel Settings
EN default value: 0
WHEEL default value: 0
Table 5-14. Slider Options
Address Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
14
EN WHEEL Reserved
0
255
1 to 254
Position (at 8 bits - 0 to 255
CH0
Tips of triangles should
be spaced 4 mm apart.
4 mm
4 mm
Position 0
Position 86
Position 170
CH1 CH2CH2
CH0
CH1
CH2