
Chapter 14
LCD Functions
Operation
XIV - 21
14-3-5
Setup Example of the LCD Driver Circuit
nSetup example of the LCD driver circuit (using internal voltage booster circuit)
An example of setup procedure to display “23” in 1/4 duty, 1/3 bias with both segment signals (SEG0 to
SEG3) and common signals (COM0 to COM3), using internal voltage booster circuit is shown below.
Refer to XIV-19. fig.14-3-6 for the LCD power supply connection. Refer to XIV-36. LCD display for
connection of LCD panel.
Setup Procedure
Description
(1)
Start the voltage booster circuit operation
LCDMD2(X’3FDA’)
bp0
: UPEN
= 1
bp1
: UPCK
= 0
(2)
Setup pins
LCDMD2(X’3FDA’)
bp7-4
: COMSL3-0
= 1111
LCCTR1(X’3FDB’)
bp0
: LC1SL0
= 1
(3)
Select the LCD clock source
LCDMD1(X’3FD9’)
bp3-0
:LCDCK3-0
= 0111
(4)
Select the LCD display duty
LCDMD1(X’3FD9’)
bp5-4
:LCDTY1-0
= 00
(5)
Setup the LCD panel display data
X’2E00’
= X’E5’
X’2E01’
= X’C7’
(6)
Start the LCD driver circuit
LCDMD1(X’3FD9’)
bp7
:LCDEN
= 1
(1)
Set the UPEN flag of the LCD mode control
register 2 (LCDMD2) to “1” to operate
voltage booster circuit. Set the UPCK flag to
“0” to set up the voltage booster speed to
normal.
(2)
Set COMSL3 to 0 flags of the LCD mode
control register 2 (LCDMD2) to “1111”, to set
up the common pins 3 to 0.
Set the LC1SL0 flag of the LCD output con-
trol register (LCCTR1) to “1”, to set up the
segment pins 3 to 0.
(3)
Select OSC1/218 as the LCD clock source by
LCDCK3 to 0 flags of the LCD mode control
register 1 (LCDMD1).
(4)
Set LCDTY1 to 0 flags of the LCD mode
control register 1 (LCDMD1) to “00” to set up
the display duty.
(5)
Set up the display data on the address
X’2E00’, X’2E01’ of the segment output latch.
[
Refer to XIV LCD Display]
(6)
Set the LCDEN flag of the LCD mode control
register 1 (LCDMD1) to “1” to start the LCD
driver circuit.