477
18.6 Operation of the LCD Controller Driver
18.6 Operation of the LCD Controller Driver
The LCD controller driver performs the control and driving required to display the LCD.
I
Explanation of LCD Controller Driver Operation
To display the LCD, the settings in Figure 18.6-1 "LCD Controller Driver Settings" are required.
Figure 18.6-1 LCD Controller Driver Settings
When the above settings are made and the selected frame cycle generating clock is oscillating,
the driving waveform of the LCD panel is output to the common and segment output pins
(COM0 to COM3, SEG0 to SEG13) in accordance with the description in the LCD display RAM
and LCRs 1 to 4.
Even during LCD display operation, the frame cycle generating clock can be switched.
However, the display may blink at the time of switching. Stop the display temporarily by
blanking (LCR1: BK = 1) before switching the clock.
The output for driving the display is two-frame alternating current waveform selected by the
setting of bias and duty.
When LCD display operation is stopped (LCR: MS1, MS0 = 00B), both the common and
segment output pins are set at the "L" level.
Note:
When the selected frame cycle oscillating clock is stopped during LCD display operation, a
DC voltage is applied to the LCD elements because the alternating current generating circuit
is stopped. In this case, the LCD display operation must be stopped in advance. The
conditions for stopping the main clock (time base timer) and subclock are dependent on the
selection of the clock mode and standby mode. When the timer base timer output is
selected (LCR1: CSS = 0), clearing the time base timer affects the frame cycle.
: Used bit
0 : 0 is set
LCD display RAM
060
H
to 066
H
Display data
BK
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
LCR1
MS1
FP1
FP0
MS0
CSS
VSEL
SEG12
LCR2
SEG11
SEG9
SEG8
SEG10
-
SEG13
LCDEN
0
Other than 00
SEG04
LCR3
SEG03
SEG01 SEG00
SEG02
SEG05
COM2
LCR4
COM1 COM0
-
-
COM3
-
SEG06
SEG07
-
-