Multiple Channel Capacitive Touch Sensor and LED Driver
Datasheet
Table 5.59 LEDx_CTL Bit Decode (continued)
LEDX_CTL
[1:0]
OPERATION
- LINKED
WITH
OPERATION -
NOT LINKED
WITH SENSOR
START
TRIGGER
STOP
TRIGGER
1
0
SENSOR
DESCRIPTION
The LED will breathe continuously
while the corresponding sensor detects
a press. When the sensor detects a
release, it will breathe 5 additional
times and then stop. The total period of
each “breath” is determined by the
LED Pulse 2 Period controls - see
Section 5.42.
Breathe Hold
+ Pulse
Release
(Pulse 2)
Press
Detected
Release
Detected
1
0
Breathe
The LED will breathe. It will be driven
with a duty cycle that ramps up from
the programmed minimum duty cycle
(default 0%) to the programmed
maximum duty cycle duty cycle and
then back down. Each ramp takes up
50% of the programmed period. The
total period of each “breath” is
Press
Detected
Release
Detected
1
1
Breathe
Breathe
determined by the LED Breathe Period
controls - see Section 5.43.
APPLICATION NOTE: The PWM frequency is determined based on the selected LED behavior, the programmed
breathe period, and the programmed min and max duty cycles. For the Direct Mode, the
PWM frequency is calculated based on the programmed Rise and Fall times. If these area
set at 0, then the maximum PWM frequency will be used based on the programmed duty
cycle settings.
5.41 LED Pulse 1 Period Register
Table 5.60 LED Behavior Registers
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
LED Pulse 1
Period
P1_
PER6
P1_
PER5
P1_
PER4
P1_
PER3
P1_
PER2
P1_
PER1
P1_
PER0
84h
R/W
-
20h
The LED Pulse 1 Period register determines the overall period of a pulse operation as determined by
the LED_CTL registers (see Table 5.59 - setting 01b). Each LSB represents 32ms so that a setting of
14h (20d) would represent a period of 640ms. The total range is from 32ms to 4.06 seconds as shown
in Table 5.61.
The Pulse 1 operation is shown in Figure 5.1 (non-inverted polarity) and Figure 5.2 (inverted polarity).
SMSC CAP1014
Revision 1.65 (08-11-09)
DATA6S9HEET
SMSC [ SMSC CORPORATION ]
