6 Channel Capacitive Touch Sensor with 2 LED Drivers
Datasheet
‘1’ - The LED2 pin is a push-pull output. When driving a logic ‘1’ the pin is driven high. When driving
a logic ‘0’ the pin is driven low.
Bit 0 - LED1_OT - Determines the output type of the LED1 pin.
5.24 Sensor LED Linking Register
Table 5.38 Sensor LED Linking Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
Sensor LED
Linking
CS2_
LED2
CS1_
LED1
72h
R/W
-
-
-
-
-
-
00h
The Sensor LED Linking registers control whether a Capacitive Touch Sensor is linked to an LED
output or not. If the corresponding bit is set, then the appropriate LED output will change states defined
by the LED Behavior controls (see Section 5.27) in response to the Capacitive Touch sensor.
Bit 1 - CS2_LED2 - Links the LED2 output to a detected touch on the CS2 sensor. When a touch is
detected, the LED is actuated and will behave as determined by the LED Behavior controls.
‘0’ (default) - The LED 2 output is not associated with a the CS2 input. If a touch is detected on
the CS2 input, then the LED will not automatically be actuated. The LED is enabled and controlled
via the LED Output Configuration register (see Section 5.24) and the LED Behavior registers (see
Section 5.27).
‘1’ - The LED 2 output is associated with the CS2 input. If a touch is detected on the CS2 input
then the LED will be actuated and behave as defined in Table 5.43.
Bit 0 - CS1_LED1 - Links the LED1 output to a detected touch on the CS1 sensor. When a touch is
detected, the LED is actuated and will behave as determined by the LED Behavior controls.
5.25 LED Polarity Register
Table 5.39 LED Polarity Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
LED2_
POL
LED1_
POL
73h
R/W
LED Polarity
-
-
-
-
-
-
00h
The LED Polarity registers control the logical polarity of the LED outputs.
APPLICATION NOTE: The polarity controls determine the final LED pin drive. A touch on a linked Capacitive Touch
Sensor is treated in the same way as the LED Output Control bit being set to a logic ‘1’.
APPLICATION NOTE: For LED operation, the duty cycle settings determine the % of time that the LED pin will be
driven to a logic ‘1’ state in a non-inverted system or to a logic ‘0’ state in an inverted system.
The duty cycle settings operate independently of the polarity controls. Therefore, the Max
Duty Cycle settings define the maximum % of time that the LED pin will be driven high in a
non-inverted system while the Min Duty Cycle settings determine the minimum % of time that
the LED pin will be driven high in a non-inverted system.
The LED drive assumes that the LEDs are configured such that if the LED pin is driven to
a logic ‘0’ then the LED will be on and that the CAP1026 LED pin is sinking the LED current.
Conversely, if the LED pin is driven to a logic ‘1’ then the LED will be off and there is no
current flow.
SMSC CAP1026
Revision 1.1 (08-05-09)
DATA5S3HEET
SMSC [ SMSC CORPORATION ]
