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
18
9634E–AT42–06/12
AT42QT2120
5. Setups
5.1 Introduction
The device calibrates and processes signals using a number of algorithms specifically designed
to provide for high survivability in the face of adverse environmental challenges. User-defined
Setups are employed to alter these algorithms to suit each application. These Setups are loaded
into the device over the I
2
C-compatible serial interfaces. In standalone mode these settings are
fixed to predetermined values.
Table 5-1. Internal Register Address Allocation
Address Use Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 R/W
0 Chip ID Chip Id = 0x3E (62) R
1 Firmware Version Major version Minor version R
2 Detection Status CALIBRATE OVERFLOW – – – – SDET TDET R
3
Key Status
KEY7 KEY6 KEY5 KEY4 KEY3 KEY2 KEY1 KEY0 R
4
Reserved KEY11 KEY10 KEY9 KEY8 R
5 Slider Position Slider position R
6 Calibrate Calibrate Command R/W
7 Reset
Reset Command R/W
8 LP Low Power (LP) Mode R/W
9TTD
0 Towards Touch Drift compensation R/W
10 ATD
0 Away from Touch Drift compensation R/W
11 DI Detection integrator R/W
12 TRD Touch Recal Delay R/W
13 DHT Drift Hold Time R/W
14 Slider Options EN WHEEL
Reserved R/W
15 Charge Time
Reserved Charge Time –
16 Key 0 Detect Threshold Detect Threshold level for key 0 R/W
17 Key 1 Detect Threshold Detect Threshold level for key 1 R/W
18 Key 2 Detect Threshold Detect Threshold level for key 2 R/W
19 Key 3 Detect Threshold Detect Threshold level for key 3 R/W
20 Key 4 Detect Threshold Detect Threshold level for key 4 R/W
21 Key 5 Detect Threshold Detect Threshold level for key 5 R/W
22 Key 6 Detect Threshold Detect Threshold level for key 6 R/W
23 Key 7 Detect Threshold Detect Threshold level for key 7 R/W
24 Key 8 Detect Threshold Detect Threshold level for key 8 R/W
25 Key 9 Detect Threshold Detect Threshold level for key 9 R/W
26 Key 10 Detect Threshold Detect Threshold level for key 10 R/W
27 Key 11 Detect Threshold Detect Threshold level for key 11 R/W
28 Key 0 Control
Reserved GUARD AKS GPO EN R/W
29 Key 1 Control
Reserved GUARD AKS GPO EN R/W
30 Key 2 Control
Reserved GUARD AKS GPO EN R/W