CAP1126 datasheet(52/73 Pages) MICROCHIP

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CAP1126

DS00001623B-page 52

 2015 Microchip Technology Inc.

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.

APPLICATION NOTE: If an LED is actuated and not linked and the desired LED behavior is changed, this new

behavior will take effect immediately; however, the first instance of the changed behavior

may act incorrectly (e.g. if changed from Direct to Pulse 1, the LED output may ‘breathe’ 4

times and then end at minimum duty cycle). LED Behaviors will operate normally once the

LED has been un-actuated and then re-actuated.

APPLICATION NOTE: If an LED is actuated and it is switched from linked to a capacitive touch sensor input to

unlinked (or vice versa), the LED will respond to the new command source immediately if

the behavior was Direct or Breathe. For Pulse behaviors, it will complete the behavior

already in progress. 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 actuated by the LED Output Control register and the control is

changed so that it is linked and no touch is detected, then the LED will behave as if a release

was detected.

Bits 3 - 2 - LED2_CTL[1:0] - Determines the behavior of LED2 as shown in Table 6-52.

Bits 1 - 0 - LED1_CTL[1:0] - Determines the behavior of LED1 as shown in Table 6-52.

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