CAP1128 Datasheet, PDF (56/75 Pages) Microchip Technology – 8 Channel Capacitive Touch Sensor with 2 LED Drivers

CAP1128
FIGURE 6-2:
Pulse 1 Behavior with Inverted Polarity
Touch Detected or
Release Detected
X pulses after touch or after release
Pulse 1 Max Duty Cycle * Brightness
LED
Brightness
Normal – untouched
operation
Pulse Period
(P1_PER)
Normal – untouched
operation
Pulse 1 Min Duty Cycle * Brightness
TABLE 6-54: LED PULSE / BREATHE PERIOD EXAMPLE
Setting (HEX)
Setting (Decimal)
00h
0
01h
1
02h
2
03h
3
...
...
7Dh
125
7Eh
126
7Fh
127
6.33 LED Pulse 2 Period Register
Total Breathe / Pulse Period (MS)
32
32
64
96
...
4000
4032
4064
TABLE 6-55: LED PULSE 2 PERIOD REGISTER
ADDR R/W
Register
B7
B6
B5
85h
R/W
LED Pulse 2
Period
-
P2_
PER6
P2_
PER5
B4
P2_
PER4
B3
P2_
PER3
B2
P2_
PER2
B1
P2_
PER1
B0
P2_
PER0
Default
14h
The LED Pulse 2 Period register determines the overall period of a pulse operation as determined by the LED_CTL
registers (see Table 6-52 - setting 10b). The LSB represents 32ms so that a setting of 18h (24d) would represent a
period of 768ms. The total range is from 32ms to 4.064 seconds (see Table 6-54) with a default of 640ms.
APPLICATION NOTE: Due to constraints on the LED Drive PWM operation, any Breathe Period less than 160ms
(05h) may not be achievable. The device will breathe at the minimum period possible as
determined by the period and min / max duty cycle settings.
The Pulse 2 Behavior is shown in Figure 6-3 for non-inverted polarity (LEDx_POL = 1) and in Figure 6-4 for inverted
polarity (LEDx_POL = 0).
DS00001622B-page 56
 2015 Microchip Technology Inc.