MC68HC08LT8 Datasheet, PDF (88/156 Pages) Freescale Semiconductor, Inc – Microcontrollers

Liquid Crystal Display (LCD) Driver
The voltage waveform across the "e" segment of the LCD (between BP2 and FP0) is illustrated in
Figure 8-15. As shown in the waveform, the voltage peaks do not reach the LCD-ON voltage, V_LCD,
therefore, the segment will be OFF.
BP2–FP0
Figure 8-15. "e" Segment Voltage Waveform
+ V_LCD
+ V_LCD1
+ V_LCD2
0
– V_LCD2
– V_LCD1
– V_LCD
8.8 I/O Registers
Fifteen (15) registers control LCD driver module operation:
• LCD control register (LCDCR)
• LCD clock register (LCDCLK)
• LCD data registers (LDAT1–LDAT13)
8.8.1 LCD Control Register (LCDCR)
The LCD control register (LCDCR):
• Enables the LCD driver module
• Selects bias resistor value and fast-charge control
• Selects LCD contrast
Address:
Read:
Write:
Reset:
$0051
Bit 7
6
0
LCDE
5
4
3
2
1
FC
LC
LCCON3 LCCON2 LCCON1
0
0
0
0
0
0
0
= Unimplemented
Figure 8-16. LCD Control Register (LCDCR)
Bit 0
LCCON0
0
LCDE — LCD Enable
This read/write bit enables the LCD driver module; the backplane and frontplane drive LCD waveforms
out of BPx and FPx pins. Reset clears the LCDE bit.
1 = LCD driver module enabled
0 = LCD driver module disabled
FC — Fast Charge
LC — Low Current
These read/write bits are used to select the value of the resistors in resistor ladder for LCD voltages.
Reset clears the FC and LC bits.
MC68HC08LT8 Data Sheet, Rev. 1
88
Freescale Semiconductor