SC230 SILAN [Silan Microelectronics Joint-stock], SC230 Datasheet - Page 9

• Manufacturer Part Number: SC230
• Description: GENERAL 32X3 SEG LCD DISPLAY DRIVER WITH 1/3 DUTY
• Manufacturer: SILAN [Silan Microelectronics Joint-stock]

KEYBOARD SCAN
1 Keyboard scan time
scan operation, and when the scan is completed (8T), output the signal which is needed by key data transmission.
2 Key data transmission
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Keyboard scan spends 4T,and it should be executed twice. Press the corresponding key, then begin the key
DI
DO
Key input 1
Key input 2
Keyboard
scan
CE
-
-
-
-
-
KS1~KS3 pins are low level
If the key is pressed, execute the key scan
If the key-press time is over 8T, the output key data transmission request signal to the host, if the host
transmits a key address, then begin to transmit the key data.
If receive the display address when output the key data request signal to the host, then make CE=H,
DO=L.
If the key data transmission is completed, it will release the request and restore the key scan.
LCD
data
8T(s)
A
LCD
data
[A] Key scan data
Key on
Key on
Key address
8T(s)
B
LCD
data
[B] Key scan data
Key address
REV:1.4
(fx = System clock)
T = 2
Page 9 of 14
Key on
13
8T(s)
/fx
2004.08.03
C
SC230