LC75700T
Pin Functions
Pin Pin No. Function Active I/O Handling when unused
KI1 to KI5 1 to 5 Key scan inputs. These pins have built-in pull-down resistors. H I GND
Key scan outputs. Although normal key scan timing lines require diodes to be
KS1 to KS3 6 to 8
inserted in the timing lines to prevent shorts, since these outputs are unbalanced
— 0 Open
CMOS transistor outputs, these outputs will not be damaged by shorting when
these outputs are used to from a key matrix.
Key scan outputs and general-purpose output ports shared-function pins.
KS4/P4 to KS6/P2 9 to 11 These pins can be set the key scan output ports or the general-purpose output — 0 Open
ports by the control data “KP1 and KP2”.
P1 12 The P1 is general-purpose output ports. — 0 Open
OSC 14
Oscillator connection. An oscillator circuit is formed by connecting an external
— I/O V
DD
resistor and capacitor at this pin.
Reset input. that re-initializes the LSI internal states. This pin must be used.
• When RES is low (V
SS
)
— Key scanning disabled: KS1 to KS3 = low (V
SS
).
— Key scan outputs and general output ports shared-function pins:
KS4/P4 to KS6/P2 = low (V
SS
).
RES 16 — General-purpose output port: P1 = low (V
SS
). L I GND
— All the key data is reset to low.
• When RES is high (V
DD
)
— The states of the pins as key scan output pins or general-purpose output
ports, must be set with the control data.
— And key scanning is a enabled.
Note that serial data must be transferred when RES is high.
CE 18
Serial data interface. Connections to the controller. Note that DO, being
H I
CL 19
an open-drain output, requires a pull-up resistor.
I GND
CE: Chip enable
CL: Synchronization clock
DI 20
DI: Transfer data
— I
DO 17
DO: Output data
— O Open
V
DD
15 Power supply. A voltage of between 2.7 V and 5.5 V must be supplied. — — —
V
SS
13 Ground. Must be connected to the system ground. — — —
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