MEC1322 Datasheet, PDF (330/456 Pages) Microchip Technology – Keyboard and Embedded Controller for Notebook PC

MEC1322
The breathing range of and LED can range between full on and full off, or in a range that falls within the full-on/full-off
range, as shown in this figure. The ramp time can be different in different applications. For example, if the ramp time
was 1 second, the LED would appear to breathe quickly. A time of 2 seconds would make the LED appear to breathe
more leisurely.
The breathing pattern can be clipped, as shown in the following figure, so that the breathing effect appears to pause at
its maximum and minimum brightnesses:
FIGURE 28-3:
CLIPPING EXAMPLE
Full on
Max Duty Cycle
Full off
Min Duty Cycle
The clipping periods at the two extremes can be adjusted independently, so that for example an LED can appear to
breathe (with a short delay at maximum brightness) followed by a longer “resting” period (with a long delay at minimum
brightness).
The brightness can also be changed in a non-linear fashion, as shown in the following figure:
FIGURE 28-4:
EXAMPLE OF A SEGMENTED CURVE
Full on
Full off
In this figure, the rise and fall curves are implemented in 4 linear segments and are the rise and fall periods are sym-
metric.
The breathing mode uses the 32.768 KHz clock for its time base.
DS00001719D-page 330
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