SC624
16
Register Map
Address D7 D6 D5 D4 D3 D2 D1 D0
Reset
Value
Description
0x00 FADE_1 FADE_0 FADE_EN BL_4 BL_3 BL_2 BL_1 BL_0 0x00
Backlight
Current
Control
0x01 0
(1)
0
(1)
0
(1)
0
(1)
BLEN_4 BLEN_3 BLEN_2 BLEN_1 0x00
Backlight
Enable Control
0x03 0
(1)
LDO2_2 LDO2_1 LDO2_0 LDO1_3 LDO1_2 LDO1_1 LDO1_0 0x00 LDO Control
Notes:
(1) 0 = always write a 0 to these bits
Register and Bit De nitions
Backlight Current Control Register (0x00)
This register is used to set the currents for the backlight
current sinks, as well as to enable and set the fade step
rate. These current sinks need to be enabled in the
Backlight Enable Control register to be active.
FADE[1:0]
These bits are used to set the rise/fall rate between two
backlight currents as follows:
FADE_1 FADE_0
Fade Feature
Rise/Fall Rate
(ms/step)
0 0 32
01 24
10 16
11 8
The number of steps in changing the backlight current will
be equal to the change in binary count of bits BL[4:0].
FADE_EN
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
operation equals the di erence 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 1.024
seconds when the default interval of 32ms is used.
