Datasheet

Liquid Crystal Display Driver (LCD)
Technical Data MC68HC908LJ12 — Rev. 2.1
320 Liquid Crystal Display Driver (LCD) Freescale Semiconductor
16.5 Functional Description
Figure 16-2 shows a block diagram of the LCD driver module, and
Figure 16-3 shows a simplified schematic of the LCD system.
The LCD driver module uses a 1/3 biasing method. The LCD power is
supplied by MCU power supply V
DD
. Voltages V
LCD1
, V
LCD2
, and V
LCD3
are generated by an internal resistor ladder.
The LCD data registers, LDAT1–LDAT14, 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.
$005A
LCD Data Register 9
(LDAT9)
Read:
F17B3 F17B2 F17B1 F17B0 F16B3 F16B2 F16B1 F16B0
Write:
Reset:UUUUUUUU
$005B
LCD Data Register 10
(LDAT10)
Read:
F19B3 F19B2 F19B1 F19B0 F18B3 F18B2 F18B1 F18B0
Write:
Reset:UUUUUUUU
$005C
LCD Data Register 11
(LDAT11)
Read:
F21B3 F21B2 F21B1 F21B0 F20B3 F20B2 F20B1 F20B0
Write:
Reset:UUUUUUUU
$005D
LCD Data Register 12
(LDAT12)
Read:
F23B3 F23B2 F23B1 F23B0 F22B3 F22B2 F22B1 F22B0
Write:
Reset:UUUUUUUU
$005E
LCD Data Register 13
(LDAT13)
Read:
F25B3 F25B2 F25B1 F25B0 F24B3 F24B2 F24B1 F24B0
Write:
Reset:UUUUUUUU
$005F
LCD Data Register 14
(LDAT14)
Read:
F26B3 F26B2 F26B1 F26B0
Write:
Reset:UUUUUUUU
U = Unaffected
= Unimplemented
Figure 16-1. LCD I/O Register Summary