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
6
9634E–AT42–06/12
AT42QT2120
1.3 Schematics
Figure 1-1. 20-pin SOIC/TSSOP – Comms Mode
Figure 1-2. 20-pin SOIC/TSSOP – Standalone Mode
VSS
VDD
R12
VSS
VDD
SCL
CHANGE
R11
R10
R9
R8
R7
R6
R5
R4
R3
R2
R1
R0
KEY8/GPO6
1
KEY7GPO5
2
KEY6/GPO4
3
KEY5/GPO3
4
KEY4/GPO2
5
KEY3/GPO1
6
KEY2/GPO0
7
KEY1
8
KEY0
9
VSS
10
VDD
11
MODE
12
SDA
13
RESET
14
N/C
15
SCL
16
CHANGE
17
KEY11/GPO9
18
KEY10/GPO8
19
KEY9/GPO7
20
SDA
R13
R14
R15
VDD
KEY 11
KEY 9
KEY 7
KEY 5
KEY 3
KEY 1
KEY 10
KEY 8
KEY 6
KEY 4
KEY 2
KEY 0
May be used for
wheel or slider
VSS
VDD
R12
VDD
R6
R5
R4
R3
R2
R1
R0
OUT3
1
OUT2
2
KEY6
3
KEY5
4
KEY4
5
KEY3
6
KEY2
7
GUARD
8
PROX
9
VSS
1
VDD
MODE
12
N/C
13
RESET
14
PXOUT
15
N/C
16
N/C
17
OUT6
18
OUT5
19
OUT4
20
R13
D
KEY 5
KEY 3
GUARD KEY
KEY 6
KEY 4
KEY 2
PROXIMITY
VDD
SENSOR
0
1
1
VSS
1
OUTPUTS