Datasheet

Liquid Crystal Display Driver (LCD)
Technical Data MC68HC908LJ12 — Rev. 2.1
326 Liquid Crystal Display Driver (LCD) Freescale Semiconductor
16.7 I/O Signals
The LCD driver module has thirty (30) output pins and shares eight of
them with port C I/O pins.
• FP0/BP3 (multiplexed; selected as FP0 or BP3 by DUTY[1:0])
• BP0–BP2
• FP1–FP26 (FP19–FP26 shared with port C)
16.7.1 BP0–BP3 (Backplane Drivers)
BP0–BP3 are the backplane driver output pins. These are connected to
the backplane of the LCD panel. Depending on the LCD duty selected,
the voltage waveforms in Figure 16-6, Figure 16-5, and Figure 16-7
appear on the backplane pins.
BP3 pin is only used when 1/4 duty is selected. The pin becomes FP0
for static and 1/3 duty operations.
Figure 16-5. 1/3 Duty LCD Backplane Driver Waveforms
1FRAME
DUTY = 1/3
BP0
V
LCD
V
LCD1
V
LCD3
V
LCD
V
LCD2
V
LCD3
V
LCD
V
LCD1
V
LCD2
V
LCD3
V
LCD2
V
LCD1
BP1
BP2
1. BP3 is not used.
2. At 1/3 duty, 1FRAME has three times the cycle of LCD waveform base clock.
NOTES: