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PC2
|
| a
pressed
key
Is
d
ed
etect
key scan stop
Conducts Key Scan.
Timing chart
41-44
PC3-PC0
KEY SOURCE
PC3
|
|
Key
Is
Pressed,
Key Return input
Key Scan
@
Set PCO, PCl, PC2 and PC3 to "High".
@
When noe of the 15 keys is pressed, PC0-PC3 will be set to "Low",
3)
Each port is set to "High" (Key scan) in the following order PC0 —
PCl — PC2 — PC3 to determine the pressed key.
K0-K3 input condition
Pco
PCI
aoras
Boe
Key Ret UR
:
The figure in the right indicates that
T]
oS [|
the key following PC1 is pressed.
-—
*
When the initial key is pressed and
SS
held down
while
the next
key is
@
@® ©)
pressed, the second key input will not be accepted until the initial
key is released (for +, — keys only). Release the initial key and
press the next key so that the second key input will be accepted.
(Eg.) When the PC3 line key is pressed.
51-56 | LCD16-LCD11 | LCD16-LCD11 | O | LCD drive
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