st2064b Sitronix Technology Corporation, st2064b Datasheet - Page 40

• Manufacturer Part Number: st2064b
• Description: 8 Bit Microcontroller With 64k Bytes Rom
• Manufacturer: Sitronix Technology Corporation

15.3 Keyboard-scan Function on LCD drives
LCD keyboard awaking pulses are combined with LCD
waveform. The purpose is to trigger Port-A interrupt to wake
up the system.
15.3.2 Keyboard-scan Function Example:
INITIAL_Port_And_LCD
Ver. 3.0
VP
VP
V1
V2
V3
V4
V5
V1
V2
V3
V4
V5
.
a.
b.
c.
.
SMB4
LDA
STA
STZ
LDA
STA
STA
LDA
STA
LDA
STA
LDA
LDA
STA
STZ
CLI
Keyboard : 64Keys (8x8)
Return Lines : Port-A
Scan Lines : Port-B
<LCTL
#000
<LSEL
<PCA
#FFH
<PA
<PCB
#11000000B
<PMCR
#00010000B
<IENA
<PA
#$FF
<PAK
<IREQ
11111B
FIGURE 15-3 LCD Segment Waveform (With Keyboard Awaking Pulses)
FIGURE 15-4 LCD Common Waveform (With Keyboard Awaking Pulses)
;;Enable Port-A Interrupt
;;Keep Port-A last state
;;Enable Keyboard Awaking Pulses Waveform
;;Set all shared pins to be segments
;;Set Port-A as Inputs for Return Line
;;Port-A Pull-High
;;Set Port-B as Outputs for Scan Line
;;Enable Pull up & Debounce
;;Port-A used as keyboard return line
;;Reset Interrupt Request Register
40/57
Note:
1. keyboard awaking pulses can only be turned
2. If there is crosstalk on the first line, please
on below 3V operating voltage.
turn on keyboard-scan function for better
quality.
P o r t - A s e t t o r e t u r n li n e )
I n it ia l I n t e r r u p t /L C D
( E n a b le D e b o u n c e &
I n it ia l I /O
C L I
.
.
.
ST2064B
5/8/09