Chapter 8 LCD Module (S08LCDLPV1)
MC9S08LG32 MCU Series, Rev. 5
176
Freescale Semiconductor
In multiplexed mode, the LCD waveforms are multi-level and depend on the bias mode. Multiplex mode,
depending on the number of backplanes, can drive multiple LCD segments with a single frontplane driver.
This reduces the number of driver circuits and connections to LCD segments. For multiplex mode
operation, at least two backplane drivers are needed. The LCD module is optimized for multiplex mode.
The duty cycle indicates the amount of time the LCD panel segment is energized during each LCD module
frame cycle. The denominator of the duty cycle indicates the number of backplanes that are being used to
drive an LCD panel.
The duty cycle is used by the backplane phase generator to set the phase outputs. The phase outputs A-H
are driven according to the sequence shown below. The sequence is repeated at the LCD frame frequency.
The duty cycle is configured using the DUTY[2:0] bit field in the LCDC0 register, as shown in
9.4.1.2
LCD Bias
Because a single frontplane driver is configured to drive more and more individual LCD segments, 3
voltage levels are required to generate the appropriate waveforms to drive the segment. The LCD module
is designed to operate using the 1/3 bias mode.
9.4.1.3
LCD Module
Base Clock and
Frame Frequency
The LCD module is optimized to operate using a 32.768 kHz clock input. Two clock sources are available
to the LCD module, which are selectable by configuring the SOURCE bit in the LCDC0 register. The two
clock sources include:
•
External crystal — OSCOUT (SOURCE = 0)
•
Alternate clock (SOURCE = 1)
shows the LCD clock tree. The clock tree shows the two possible clock sources and the LCD
frame frequency and blink frequency clock source. The LCD blink frequency is discussed in
Section 9.4.3.2, “Blink Frequency
.”
Table 9-11. LCD Module Duty Cycle Modes
Duty
LCDC0 Register
Number of Backplanes
Phase
Sequence
DUTY2
DUTY1
DUTY0
1/1
0
0
0
1
A
1/2
0
0
1
2
A B
1/3
0
1
0
3
A B C
1/4
0
1
1
4
A B C D
1/5
1
0
0
5
A B C D E
1/6
1
0
1
6
A B C D E F
1/7
1
1
0
7
A B C D E F G
1/8
1
1
1
8
A B C D E F G H
Содержание MC9S08LG16
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Страница 26: ...Chapter 1 Device Overview MC9S08LG32 MCU Series Rev 5 26 Freescale Semiconductor...
Страница 40: ...Chapter 2 Pins and Connections MC9S08LG32 MCU Series Rev 5 40 Freescale Semiconductor...
Страница 96: ...Chapter 5 Resets Interrupts and General System Control MC9S08LG32 MCU Series Rev 5 96 Freescale Semiconductor...
Страница 296: ...Chapter 12 Serial Peripheral Interface S08SPIV4 MC9S08LG32 MCU Series Rev 5 296 Freescale Semiconductor...
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