CAP1214 Datasheet, PDF (65/107 Pages) SMSC Corporation – Multiple Channel Capacitive Touch Sensor and LED Driver

Multiple Channel Capacitive Touch Sensor and LED Driver
Note 6.1
Datasheet
Recalibration Samples refers to the number of samples that are measured and averaged
before the Base Count is updated.
Note 6.2 Update Time refers to the amount of time (in polling cycle periods) that elapses before the
Base Count is updated.
6.28 Sensor Threshold Registers
Table 6.40 Sensor Threshold Registers
ADDR R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0 DEFAULT
30h
R/W
Sensor 1
Threshold
-
64
32
16
8
4
2
1
40h
31h
R/W
Sensor 2
Threshold
-
64
32
16
8
4
2
1
40h
32h
R/W
Sensor 3
Threshold
-
64
32
16
8
4
2
1
40h
33h
R/W
Sensor 4
Threshold
-
64
32
16
8
4
2
1
40h
34h
R/W
Sensor 5
Threshold
-
64
32
16
8
4
2
1
40h
35h
R/W
Sensor 6
Threshold
-
64
32
16
8
4
2
1
40h
36h
R/W
Sensor 7
Threshold
-
64
32
16
8
4
2
1
40h
37h
R/W
Group
Threshold
-
64
32
16
8
4
2
1
40h
The Sensor Threshold Registers store the delta threshold that is used to determine if a touch has been
detected. When a touch occurs, the input signal of the corresponding sensor changes due to the
capacitance associated with a touch. If the sensor input change exceeds the threshold settings, a
touch is detected.
When the BUT_LD_TH bit is set (see Section 6.27 - bit 7), writing data to the Sensor 1 Threshold
register will update all of the button threshold registers (31h - 36h inclusive).
When the GP_LD_TH bit is set (see Section 6.27 - bit 6), writing data to the Sensor 1 Threshold
register (30h) will update the Group Threshold register (37h).
Individual button registers and the Group Threshold register may be updated independently of the
Sensor 1 Threshold settings.
SMSC CAP1214
65
DATASHEET
Revision 1.0 (08-30-10)