Datasheet

Liquid Crystal Display (LCD) Driver
Low-Power Modes
MC68HC908LJ24/LK24 — Rev. 2.1 Data Sheet
Freescale Semiconductor Liquid Crystal Display (LCD) Driver 357
Figure 17-4. Fast Charge Timing
17.5.5 Contrast Control
The contrast of the connected LCD panel can be adjusted by configuring
the LCCON[3:0] bits in the LCD control register. The LCCON[3:0] bits
provide a 16-step contrast control, which adjusts the bias voltage in the
resistor ladder for LCD voltage, V
LCD3
. The relative voltages, V
LCD1
and
V
LCD2
, are altered accordingly. For example, setting LCCON[3:0] = $F,
the relative panel potential voltage (V
LCD
– V
LCD3
) is reduced from
maximum 3.3V to approximate 2.45V.
The V
LCD
voltage can be monitored by the ADC channel, ADC7, and
then adjustments to the bias voltage by the user software to provide
automatic contrast control.
17.6 Low-Power Modes
The STOP and WAIT instructions put the MCU in low power-
consumption standby modes.
LCD WAVEFORM
FAST CHARGE CLOCK
LCDCLK
HIGH CURRENT SELECTED BEFORE SWITCHING EDGE,
PERIOD IS DEFINED BY FCCTL[1:0]
EXAMPLE: BP0