Datasheet

Liquid Crystal Display Driver (LCD)
MC68HC908LJ12 — Rev. 2.1 Technical Data
Freescale Semiconductor Liquid Crystal Display Driver (LCD) 321
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.
Figure 16-2. LCD Block Diagram
16.5.1 LCD Duty
The setting of the LCD output waveform duty is dependent on the
number of backplane drivers required. Three LCD duties are available:
• Static duty — BP0 is used only
• 1/3 duty — BP0, BP1, and BP3 are used
• 1/4 duty — BP0, BP1, BP2, and BP3 are used
When the LCD driver module is enabled the backplane waveforms for
the selected duty are driven out of the backplane pins. The backplane
waveforms are periodic and are shown are shown in Figure 16-6,
Figure 16-5, and Figure 16-7.
LCD FRONTPLANE DRIVER AND DATA LATCH
PORT-C LOGIC
BACKPLANE
DRIVER
LCDE (LCDC)
STATE
CONTROL
1/4
1/3
1/3
1/4
1/1
PTC7/FP26
PTC6/FP25
PTC5/FP24
PTC4/FP23
PTC3/FP22
PTC2/FP21
PTC1/FP20
PTC0/FP19
FP5 FP6 FP7 FP8 FP9 FP10 FP11 FP12 FP13 FP14 FP15 FP16 FP17 FP18
BP0
BP1
BP2
FP0/BP3
FP1
FP2
FP3
FP4
INTERNAL BUS