8 Channel Capacitive Touch Sensor with 8 LED Drivers
Datasheet
Bit 7 - LED8_DR - Determines whether the LED8 output is driven high or low.
‘0’ (default) - The LED8 output is driven at the minimum duty cycle or not actuated.
‘1’ - The LED8 output is driven at the maximum duty cycle or is actuated.
Bit 6 - LED7_DR - Determines whether LED7 output is driven high or low.
Bit 5 - LED6_DR - Determines whether LED6 output is driven high or low.
Bit 4 - LED5_DR - Determines whether LED5 output is driven high or low.
Bit 3 - LED4_DR - Determines whether LED4 output is driven high or low.
Bit 2 - LED3_DR - Determines whether LED3 output is driven high or low.
Bit 1 - LED2_DR - Determines whether LED2 output is driven high or low.Bit 0 - LED1_DR -
Determines whether LED1 output is driven high or low.
5.27 LED Behavior Registers
Table 5.42 LED Behavior Registers
B7 B6 B5 B4 B3
ADDR
R/W
REGISTER
B2
B1
B0
DEFAULT
81h
82h
R/W
R/W
LED Behavior 1
LED Behavior
LED4_CTL[1:0]
LED8_CTL[1:0]
LED3_CTL[1:0] LED2_CTL[1:0]
LED7_CTL[1:0] LED6_CTL[1:0]
LED1_CTL[1:0]
LED5_CTL[1:0]
00h
00h
The LED Behavior registers control the operation of LEDs. Each LED pin is controlled by a 2-bit field
and the behavior is determined by whether the LED is linked to a Capacitive Touch Sensor or not.
If the corresponding LED output is linked to a Capacitive Touch Sensor than the Start and Stop triggers
are used. The defined behavior will activate when the Start Trigger is met and will stop when the Stop
Trigger is met.
If the LED output is not associated with a a Capacitive Touch Sensor, then the appropriate behavior
will be enabled / disabled by the LED Output Control register. If the respective LEDx_DR bit is set to
a logic ‘1’ then this will be associated as a “touch” and if the LEDx_DR bit is set to a logic ‘0’ then this
will be associated as a “release”.
The LED Polarity Control register will determine the non actuated state of the LED outputs. If the LED
Polarity Control register is set to be inverted (default), then an non actuated LED pin will be driven to
a logic ‘1’ state and the LED will be off. If the LED Polarity Control register is set to be non-inverted,
then the non actuated LED pin will be driven to the logic ’0’ state and the LED will be on.
APPLICATION NOTE: If an LED is not linked to a Capacitive Touch Sensor and is breathing (via the Breathe or
Pulse behaviors), it will finish its current “breath” before any changes to behavior are
processed.
APPLICATION NOTE: If an LED is not linked to the Capacitive Touch Sensor and configured to operate using Pulse
1 Behavior, then the circuitry will only be actuated when the corresponding bit is set. It will
not check the bit condition until the Pulse 1 behavior is finished. The device will not
remember if the bit was cleared and reset while it was actuated.
APPLICATION NOTE: If an LED is actuated and it is switched from linked to a Capacitive Touch Sensor to unlinked
(or vice versa), then the LED will respond to the new command source immediately. For
example, if a linked LED was actuated by a touch and the control is changed so that it is
unlinked, it will check the status of the corresponding LED Output Control bit. If that bit is ‘0’,
then the LED will behave as if a release was detected. LIkewise, if an unlinked LED was
SMSC CAP1088
Revision 1.1 (08-05-09)
DATA5S7HEET
SMSC [ SMSC CORPORATION ]
