MC68HC908LJ12 Datasheet, PDF (324/413 Pages) Freescale Semiconductor, Inc – 8-bit microcontroller units

Liquid Crystal Display Driver (LCD)
16.5.5 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 according. 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.
16.6 Low-Power Modes
The STOP and WAIT instructions put the MCU in low power-
consumption standby modes.
16.6.1 Wait Mode
The LCD driver module continues normal operation in wait mode. If the
LCD is not required in wait mode, power down the LCD module by
clearing the LCDE bit before executing the WAIT instruction.
16.6.2 Stop Mode
For continuous LCD module operation in stop mode, the oscillator stop
mode enable bit (STOP_XCLKEN in CONFIG2 register) must be set
before executing the STOP instruction. When STOP_XCLKEN is set,
CGMXCLK continues to drive the LCD module.
If STOP_XCLKEN bit is cleared, the LCD module is inactive after the
execution of a STOP instruction. The STOP instruction does not affect
LCD register states. LCD module operation resumes after an external
interrupt. To further reduce power consumption, the LCD module should
be powered-down by clearing the LCDE bit before executing the STOP
instruction.
MC68HC908LJ12 — Rev. 2.1
Freescale Semiconductor
Liquid Crystal Display Driver (LCD)
Technical Data
325