at42qt2100 ATMEL Corporation, at42qt2100 Datasheet - Page 26

• Manufacturer Part Number: at42qt2100
• Description: Qtouch Touch Sensor Ic
• Manufacturer: ATMEL Corporation

5.3
5.3.1
5.3.2
5.3.3
26
“Custom Threshold”
AT42QT2100
Introduction
Host Data
QT2100 Data
The “Custom Threshold” command mode (Req = 100) is used to modify the detection
threshold of the slider/wheel. It only needs to be sent once, for the new value to take effect,
and then the “Normal Exchange” mode resumes (see
will be in use until the chip is reset or a new custom threshold is sent.
In “Custom Threshold” command mode the host sends the 3-byte data in
Table 5-8.
Byte 0
Byte 1
Byte 2
The QT2100’s response to the “Custom Threshold” command is the “Normal Exchange”
report.
Once the custom thresholds have been set, the CTL bit in the “Normal Exchange” report is set
to “1” to indicate that the changed threshold has been applied (see
Note:
Host
Byte
Req – Set to 100 to indicate “Custom Threshold” command mode.
T1: Custom threshold value of the slider/wheel. Higher numbers are less sensitive. Touch
detection uses this threshold combined with a hysteresis equal to 25 percent of the
threshold (with a minimum hysteresis value of one).
Power-up default setting: 30
Note: Custom Threshold Command is only used if the detection threshold of the
Always set to 0.
0
1
2
Bits labelled “0” should not be altered
slider/wheel needs to be changed from the power-up default.
“Custom Threshold” Command Mode – Host Command Bytes
7
0
Req = 100
6
0
5
0
T1 – Slider/Wheel Threshold
4
0
0
Bit
Section 5.2 on page
3
0
0
2
0
0
Table
Table
5-7).
20). The new value
1
0
0
9554CX–AT42–11/11
5-8.
0
0
0