GMS81C5108
74
JUNE 2001 Ver 1.0
19.4 Control Method of LCD Driver
Initial Setting
Flow chart of initial setting is shown in Figure 19-6.
Example: Driving of LCD
.
Figure 19-6 Initial Setting of LCD Driver
Figure 19-7 Example of Connection COM & SEG
Display Data
Normally, display data are kept permanently in the pro-
gram memory and then stored at the display data area by
the table look-up instruction. This can be explained using
character display with 1/4 duty LCD as an example as well
as any LCD panel. The COM and SEG connections to the
LCD and display data are the same as those shown is Fig-
ure 19-7. Following is showing the Programming example
for displaying character.
Note: When power on RESET, sub oscillation start up time
is required. Enable LCD display after sub oscillation is sta-
bilized, or LCD may occur flicker at power on time shortly.
Clear
LCD Display
Memory
Select Frame Frequency
Turn on LCD
LDM
LCR,#12H
;f
F
=64Hz, 1/4 duty
(f
SUB
= 32.768kHz)
:
LDM
RPR,#1
;Select LCD Memory(1 page)
SETG
LDX
#0
C_LCD1:
LDA
#0
;RAM Clear
;(0100H->0124H)
STA
{X}+
CMPX
#025H
BNE
C_LCD1
CLRG
:
SET1
LCR.5
;Enable display
:
Setting of LCD drive method
Initialize of display memory
Enable display
SEG0
SEG1
COM3
COM0
COM1
COM2
Example: display “2”
1
1
1
0
0
1
0
1
*
*
*
*
*
*
*
*
100
H
101
H
3
1
2
0
bit 7
5
6
4
Note: * are don’t care.
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