MC68HC08LT8 Datasheet, PDF (81/156 Pages) Freescale Semiconductor, Inc – Microcontrollers

8.6 I/O Signals
The LCD driver module has twenty-eight (28) output pins.
• FP0/BP3 (multiplexed; selected as FP0 or BP3 by DUTY[1:0])
• BP0–BP2
• FP1–FP2 (shared with port B)
• FP3–FP10 (shared with port E)
• FP11–FP18 (shared with port D)
• FP19–FP24 (shared with port C)
I/O Signals
8.6.1 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 8-5, Figure 8-6, and Figure 8-7
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.
DUTY = STATIC
1FRAME
BP0
NOTES:
1. BP1, BP2, and BP3 are not used.
2. At static duty, 1FRAME is equal to the cycle of LCD waveform base clock.
Figure 8-5. Static LCD Backplane Driver Waveform
DUTY = 1/3
1FRAME
BP0
V_LCD
V_LCD1
V_LCD2
V_LCD3
V_LCD
V_LCD1
V_LCD2
V_LCD3
V_LCD
BP1
V_LCD1
V_LCD2
V_LCD3
BP2
NOTES:
1. BP3 is not used.
2. At 1/3 duty, 1FRAME has three times the cycle of LCD waveform base clock.
Figure 8-6. 1/3 Duty LCD Backplane Driver Waveforms
V_LCD
V_LCD1
V_LCD2
V_LCD3
MC68HC08LT8 Data Sheet, Rev. 1
Freescale Semiconductor
81