SC653 datasheet(20/22 Pages) SEMTECH

20 / 22 page

SC653

FADE_EN [D0]

This bit is used to enable or disable the fade feature. When

the fade function is enabled and a new backlight current

is set, the backlight current will change from its current

value to a new value set by bits BL[4:0] at a rate of 8ms to

32ms per step. A new backlight level cannot be written

during an ongoing fade operation, but an ongoing fade

operation may be cancelled by resetting the fade bit.

Clearing the fade bit during an ongoing fade operation

changes the backlight current immediately to the value of

BL[4:0]. The number of counts to complete a fade opera-

tion equals the difference between the old and new

backlight values to increment or decrement the BL[4:0]

bits. If the fade bit is cleared, the current level will change

immediately without the fade delay. The rate of fade may

be changed dynamically, even while a fade operation is

active, by writing new values to the FADE_1 and FADE_0

bits. The total fade time is determined by the number of

steps between old and new backlight values, multiplied

by the rate of fade in ms/step. The longest elapsed time

for a full scale fade-out of the backlight is nominally 938ms

when the default interval of 32ms is used.

SC653 Datasheet(PDF) 20 Page - Semtech Corporation