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LCD Driver IC
PT6584
Example: S0=0, S1=1 (sleep with only KS6 high)
(L) KS 1
(L) KS 2
(L) KS 3
(L) KS 4
(L) KS 5
(H) KS6
∗
When any one o f th ese keys is pressed,
the oscilla tor on the OSC pin is starte d
and the keys are scann ed.
KI1
KI2
KI3
KI4
KI5
Note:
*: These diodes are required to reliable recognize multiple key presses on the KS6 line when sleep
mode state with only KS6 high, as in the above example. That is, these diodes prevent incorrect
operations due to sneak currents in the KS6 key scan output signal when keys on the KS1 to KS5
lines are pressed at the same time.
Key Input
(KS6 line)
Key scan
800T[s]
800T[s]
CE
Key address (43H)
Key address
Serial data transfer
Serial data transfer
Serial data transfer
DI
DO
Key data read
Key data read
1
fosc
Key data read request
Key data read request
T=
MULTIPLE KEY PRESSES
Although the PT6584 is capable of key scanning without inserting diodes for dual key presses, triple
key presses on the KI1 to KI5 input pin lines, or multiple key presses on the KS1 to KS6 output pin lines,
multiple presses other than these cases may result in keys that were not pressed recognized as having
been pressed. Therefore, a diode must be inserted in series with each key. Applications that do not
recognize multiple key presses of three or more keys should check the key data for three or more 1 bits
and ignore such data.
PT6584 V1.1
- 19 -
August, 2006
PTC [ PRINCETON TECHNOLOGY CORP ]
