µPD16432B
(2) Using KEYn
If any key is set to the ON state, the standby mode is released and OSC oscillation starts. Also, KEY REQ is set
to “H”, informing the microcomputer that a key has been pressed and standby mode has been released. In this
state, the key data is not memorized, and therefore it is necessary to set key scanning to the normal state after
the standby transition time, and fetch the key data.
Example of Use of KEYn
Item
Standby mode
Key data present
Standby transition time
Status command
Key scan
Data setting command
Key data
Key data
Key data
Key data
End
Command/Data
STB
b7 b6 b5 b4 b3 b2 b1 b0
Description
L
L
Standby release (KEY REQ = H,
OSC oscillation start)
L
10 µsNote
H 1 1 0 0 1 0 0 1 LCD forced off (unselected waveform),
LED forced off, key scan operation
L
1 frame or more
H 0 1 0 0 0 1 0 0 Key data read, address increment
H
* * * * * * * * For KS8, KS7
H
* * * * * * * * For KS6, KS5
H
* * * * * * * * For KS4, KS3
H
* * * * * * * * For KS2, KS1
L
Key distinction
Note If LCD normal operation or key scan operation is initiated within the standby transition time, the LCD
may flicker.
15