PT6584 Datasheet, PDF (19/42 Pages) Princeton Technology Corp – LCD Driver IC

LCD Driver IC
Example: S0=0, S1=1 (sleep with only KS6 high)
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PT6584
(L) KS 1
(L) KS 2
(L) KS 3
(L) KS 4
(L) KS 5
(H) KS6
KI1
KI2
KI3
KI4
KI5
W hen any one o f th ese key s is pres s ed,
th e o s ci l la to r o n th e O S C p i n is s ta r te d
and the k ey s are s cann ed.
∗
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
80 0T[s]
80 0T[s]
CE
Se rial da ta tran sfe r Se rial da ta tran sfe r Ke y ad dre ss (43 H) Se rial da ta tran sfe r
DI
Ke y ad dre ss
DO
Ke y da ta r ead re que st
Ke y da ta r ead
Ke y da ta r ead
Ke y da ta r ead re que st
T=
1
fosc
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