MC68HC908LJ24 Datasheet, PDF (353/464 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Liquid Crystal Display (LCD) Driver
Functional Description
17.5 Functional Description
Figure 17-2 shows a block diagram of the LCD driver module, and
Figure 17-3 shows a simplified schematic of the LCD system.
The LCD driver module uses a 1/3 biasing method. The LCD power is
supplied by the V_LCD pin. Voltages V_LCD1, V_LCD2, and V_LCD3 are
generated by an internal resistor ladder.
The LCD data registers, LDAT1–LDAT17, control the LCD segments’
ON/OFF, with each data register controlling two frontplanes. When a
logic 1 is written to a FxBx bit in the data register, the corresponding
frontplane-backplane segment will turn ON. When a logic 0 is written, the
the segment will turn OFF.
When the LCD driver module is disabled (LCDE = 0), the LCD display
will be OFF, all backplane and frontplane drivers have the same
potential as V_DD. The resistor ladder is disconnected from V_DD to reduce
power consumption.
FP4
FP3
FP2
FP1
FP0/BP3
BP2
BP1
BP0
PORT-E LOGIC
LCD FRONTPLANE DRIVER AND DATA LATCH
1/3
1/4
LCDE (LCDC)
STATE
CONTROL
1/1 1/3 1/4
Figure 17-2. LCD Block Diagram
MC68HC908LJ24/LK24 — Rev. 2
MOTOROLA
Liquid Crystal Display (LCD) Driver
For More Information On This Product,
Go to: www.freescale.com
PTC0/FP19
PTC1/FP20
PTC2/FP21
PTC3/FP22
PTC4/FP23
PTC5/FP24
PTC6/FP25
PTC7/FP26
FP27
FP28
FP29
FP30
FP31
FP32
Data Sheet
353