MC9S12HZ256 Datasheet, PDF (251/692 Pages) Freescale Semiconductor, Inc – HCS12 Microcontrollers

Chapter 8 Liquid Crystal Display (LCD32F4BV1)
Duty
1/1
1/2
1/3
1/4
LCDCR0 Register
DUTY1
0
1
1
0
DUTY0
1
0
1
0
Table 8-8. LCD Duty and Bias
Backplanes
Bias (BIAS = 0)
BP3 BP2 BP1 BP0 1/1
1/2
1/3
OFF OFF OFF BP0 YES NA
NA
OFF OFF BP1 BP0 NA YES NA
OFF BP2 BP1 BP0 NA
NA YES
BP3 BP2 BP1 BP0 NA
NA YES
Bias (BIAS = 1)
1/1 1/2 1/3
YES NA NA
NA NA YES
NA NA YES
NA NA YES
8.4.2 Operation in Wait Mode
The LCD32F4B driver system operation during wait mode is controlled by the LCD stop in wait
(LCDSWAI) bit in the LCD control register 1 (LCDCR1). If LCDSWAI is reset, the LCD32F4B driver
system continues to operate during wait mode. If LCDSWAI is set, the LCD32F4B driver system is turned
off during wait mode. In this case, the LCD waveform generation clocks are stopped and the LCD32F4B
drivers pull down to VSSX those frontplane and backplane pins that were enabled before entering wait
mode. The contents of the LCD RAM and the LCD registers retain the values they had prior to entering
wait mode.
8.4.3 Operation in Pseudo Stop Mode
The LCD32F4B driver system operation during pseudo stop mode is controlled by the LCD run in pseudo
stop (LCDRPSTP) bit in the LCD control register 1 (LCDCR1). If LCDRPSTP is reset, the LCD32F4B
driver system is turned off during pseudo stop mode. In this case, the LCD waveform generation clocks
are stopped and the LCD32F4B drivers pull down to VSSX those frontplane and backplane pins that were
enabled before entering pseudo stop mode. If LCDRPSTP is set, the LCD32F4B driver system continues
to operate during pseudo stop mode. The contents of the LCD RAM and the LCD registers retain the
values they had prior to entering pseudo stop mode.
8.4.4 Operation in Stop Mode
All LCD32F4B driver system clocks are stopped, the LCD32F4B driver system pulls down to VSSX those
frontplane and backplane pins that were enabled before entering stop mode. Also, during stop mode, the
contents of the LCD RAM and the LCD registers retain the values they had prior to entering stop mode.
As a result, after exiting from stop mode, the LCD32F4B driver system clocks will run (if LCDEN = 1)
and the frontplane and backplane pins retain the functionality they had prior to entering stop mode.
8.4.5 LCD Waveform Examples
Figure 8-9 through Figure 8-13 show the timing examples of the LCD output waveforms for the available
modes of operation.
MC9S12HZ256 Data Sheet, Rev. 2.04
Freescale Semiconductor
251