Product data

HD404818 Series
7
Pin Functions
Power Supply
V
CC
: Apply the V
CC
power supply voltage to this pin.
GND: Connect to ground.
TEST: For test purposes only. Connect it to V
CC
.
RESET: MCU reset pin. Refer to the Reset section for details.
NUMG: Non-user pin. Connect it to GND.
NUMO: Non-user pin. Do not connect it to any lines.
Oscillators
OSC
1
, OSC
2
: Internal oscillator input pins. They both can be connected to a crystal, ceramic resonator, or
external oscillator circuit. Refer to the Internal Oscillator Circuit section for details.
X1, X2: Watch oscillator 32-kHz crystal pins.
Ports
D
0
–D
13
(D Port): Fourteen 1-bit I/O ports. D
0
to D
9
are I/O ports and D
10
to D
13
are input ports. D
0
–D
9
are
high current output ports (15 mA max.). D
11
–D
13
are also available as voltage comparators. Refer to the
Input/Output section for details.
R0–R3 (R Ports): 4-bit I/O ports. R0
0
, R0
1
, R0
2
, R3
1
, R3
2
, and R3
3
are multiplexed with SCK, SI, SO,
TIMO, INT
0
, and INT
1
, respectively.
Interrupts
INT
0
, INT
1
: External interrupt pins. INT
1
can be used as an external event input pin for timer B. INT
0
and
INT
1
are multiplexed with R3
2
and R3
3
, respectively. For details, see the Interrupts section.
Serial Interface
SCK, SI, SO: The transmit clock I/O pin (SCK), serial data input pin (SI), and serial data output pin (SO)
are used for serial interface. SCK, SI, and SO are multiplexed with R0
0
, R0
1
, and R0
2
, respectively. For
details, see the Serial Interface section.
Timer
TIMO: Variable duty-cycle pulse waveform output pin. See the Timer C section for details.