CAP1208 Datasheet, PDF (45/67 Pages) Microchip Technology – 8-Channel Capacitive Touch Sensor

8-Channel Capacitive Touch Sensor
Datasheet
B_MULT_T[1:0]
1
0
0
0
0
1
1
0
1
1
Table 5.24 B_MULT_T Bit Decode
NUMBER OF SIMULTANEOUS TOUCHES
1 (default)
2
3
4
5.15 Multiple Touch Pattern Configuration Register
ADDR
2Bh
Table 5.25 Multiple Touch Pattern Configuration
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0 DEFAULT
R/W
Multiple Touch
Pattern Config
MTP_ EN
-
-
-
MTP_TH[1:0]
COMP_ MTP_
PTRN ALERT
00h
The Multiple Touch Pattern Configuration register controls the settings for the multiple touch pattern
detection circuitry. This circuitry works like the multiple touch detection circuitry with the following
differences:
1. The detection threshold is a percentage of the touch detection threshold as defined by the
MTP_TH[1:0] bits whereas the multiple touch circuitry uses the touch detection threshold.
2. The MTP detection circuitry either will detect a specific pattern of sensor inputs as determined by
the Multiple Touch Pattern register settings or it will use the Multiple Touch Pattern register settings
to determine a minimum number of sensor inputs that will cause the MTP circuitry to flag an event
(see Section 5.16, "Multiple Touch Pattern Register"). When using pattern recognition mode, if all
of the sensor inputs set by the Multiple Touch Pattern register have a delta count greater than the
MTP threshold or have their corresponding Noise Flag Status bits set, the MTP bit will be set. When
using the absolute number mode, if the number of sensor inputs with thresholds above the MTP
threshold or with Noise Flag Status bits set is equal to or greater than this number, the MTP bit
will be set.
3. When an MTP event occurs, all touches are blocked and an interrupt is generated.
4. All sensor inputs will remain blocked so long as the requisite number of sensor inputs are above
the MTP threshold or have Noise Flag Status bits set. Once this condition is removed, touch
detection will be restored. Note that the MTP status bit is only cleared by writing a ‘0’ to the INT
bit once the condition has been removed.
Bit 7 - MTP_EN - Enables the multiple touch pattern detection circuitry.
 ‘0’ (default) - The MTP detection circuitry is disabled.
 ‘1’ - The MTP detection circuitry is enabled.
Bits 3 - 2 - MTP_TH[1:0] - Determine the MTP threshold, as shown in Table 5.26. This threshold is a
percentage of sensor input threshold (see Section 5.19, "Sensor Input Threshold Registers") for inputs
enabled in the Active state or of the standby threshold (see Section 5.24, "Standby Threshold
Register") for inputs enabled in the Standby state.
 2014 Microchip Technology Inc.
DS00001570B-page 45