CAP1128 datasheet(53/75 Pages) MICROCHIP

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DS00001622B-page 53

CAP1128

Bit 0 - LED1_LTRAN - Determines the transition effect when LED1 is linked to CS1.

6.30

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 CAP1128 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 6.6).

Bit 1 - LED2_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 0 - LED1_MIR_EN - Determines whether the duty cycle settings are “biased” relative to 0% or 100% duty cycle.

6.31

LED Behavior Register

The LED Behavior register controls 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 input or not.

If the corresponding LED output is linked to a capacitive touch sensor input, the appropriate behavior will be enabled /

disabled based on touches and releases.

If the LED output is not associated with a capacitive touch sensor input, the appropriate behavior will be enabled / dis-

abled by the LED Output Control register. If the respective LEDx_DR bit is set to a logic ‘1’, this will be associated as a

“touch”, and if the LEDx_DR bit is set to a logic ‘0’, this will be associated as a “release”.

Table 6-52, "LEDx_CTL Bit Decode" shows the behavior triggers. The defined behavior will activate when the Start Trig-

ger is met and will stop when the Stop Trigger is met. Note the behavior of the Breathe Hold and Pulse Release option.

The LED Polarity Control register will determine the non actuated state of the LED outputs (see Section 6.27, "LED

Polarity Register").

APPLICATION NOTE: If an LED is not linked to a capacitive touch sensor input and is breathing (via the Breathe

or Pulse behaviors), it must be unactuated and then re-actuated before changes to behavior

are processed. For example, if the LED output is breathing and the Maximum duty cycle is

changed, this change will not take effect until the LED output control register is set to ‘0’ and

then re-set to ‘1’.

APPLICATION NOTE: If an LED is not linked to the capacitive touch sensor input and configured to operate using

Pulse 1 Behavior, then the circuitry will only be actuated when the corresponding output

control 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.

TABLE 6-50:

LED MIRROR CONTROL REGISTER

ADDR

R/W

Default

79h

R/W

LED Mirror Con-

trol

LED2_

MIR _

LED1_

MIR _

00h

TABLE 6-51:

LED BEHAVIOR REGISTER

ADDR

R/W

Default

81h

R/W

LED Behavior 1

LED2_CTL[1:0]

LED1_CTL[1:0]

00h

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