Datasheet

8 Channel Capacitive Touch Sensor with 8 LED Drivers
Datasheet
Revision 1.32 (01-05-12) 70 SMSC CAP1188
DATASHEET
APPLICATION NOTE: If the LED behavior is not “Direct” and the INV_LINK_TRAN bit it ‘0’, the LED will not perform
as expected when the LED8_LTRAN bit is set to ‘1’. Therefore, if breathe and pulse
behaviors are used, set the INV_LINK_TRAN bit to ‘1’.
Bit 6 - LED7_LTRAN - Determines the transition effect when LED7 is linked to CS7.
Bit 5 - LED6_LTRAN - Determines the transition effect when LED6 is linked to CS6.
Bit 4 - LED5_LTRAN - Determines the transition effect when LED5 is linked to CS5.
Bit 3 - LED4_LTRAN - Determines the transition effect when LED4 is linked to CS4.
Bit 2 - LED3_LTRAN - Determines the transition effect when LED3 is linked to CS3.
Bit 1 - LED2_LTRAN - Determines the transition effect when LED2 is linked to CS2.
Bit 0 - LED1_LTRAN - Determines the transition effect when LED1 is linked to CS1.
5.30 LED Mirror Control Register
The LED Mirror Control Registers determine the meaning of duty cycle settings when polarity is non-
inverted for each LED channel. When the polarity bit is set to ‘1’ (non-inverted), to obtain correct steps
for LED ramping, pulse, and breathe behaviors, the min and max duty cycles need to be relative to
100%, rather than the default, which is relative to 0%.
APPLICATION NOTE: The LED drive assumes that the LEDs are configured such that if the LED pin is driven to
a logic ‘0’, the LED will be on and the CAP1188 LED pin is sinking the LED current. When
the polarity bit is set to ‘1’, it is considered non-inverted. For systems using the opposite LED
configuration, mirror controls would apply when the polarity bit is ‘0’.
These bits are changed automatically if the corresponding LED Polarity bit is changed (unless the
BLK_POL_MIR bit is set - see Section 5.6).
Bit 7 - LED8_MIR_EN - Determines whether the duty cycle settings are “biased” relative to 0% or 100%
duty cycle.
‘0’ (default) - The duty cycle settings are determined relative to 0% and are determined directly with
the settings.
‘1’ - The duty cycle settings are determined relative to 100%.
Bit 6 - LED7_MIR_EN - Determines whether the duty cycle settings are “biased” relative to 0% or 100%
duty cycle.
Bit 5 - LED6_MIR_EN - Determines whether the duty cycle settings are “biased” relative to 0% or 100%
duty cycle.
Bit 4 - LED5_MIR_EN - Determines whether the duty cycle settings are “biased” relative to 0% or 100%
duty cycle.
Bit 3 - LED4_MIR_EN - Determines whether the duty cycle settings are “biased” relative to 0% or 100%
duty cycle.
Table 5.50 LED Mirror Control Register
ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT
79h R/W
LED Mirror
Control
LED8_
MIR _
EN
LED7_
MIR _
EN
LED6_
MIR _
EN
LED5_
MIR _
EN
LED4_
LMIR_
EN
LED3_
MIR_
EN
LED2_
MIR _
EN
LED1_
MIR _
EN
00h