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Table 1-4 lists the pin functions for the HD404344R and HD404394 Series microcomputers.
Table 1-4
HD404344R and HD404394 Series Pin Functions
Type
Symbol
I/O
Function
Power supply
V
CC
—
Power supply: Connect to the system power supply.
GND
—
Ground: Connect to the system ground
V
ref
—
Analog reference voltage (HD404394 Series):
Connection for the A/D converter internal resistor
ladder power supply.
Clock
OSC
1
Input
System clock oscillator connection 1: Connect a
ceramic oscillator or an oscillator circuit to this pin.
Alternately, for CR oscillation a resistor should be
connected. Use an oscillator with a clock frequency
between 400 kHz and 4.5 MHz. See section 13,
“Oscillator Circuits,” for examples of the circuits used
when connecting a ceramic oscillator or resistor, or
when using an external clock input.
OSC
2
Output System clock oscillator connection 2: Connect a
ceramic oscillator to this pin. Use an oscillator with a
frequency of between 400 kHz and 4.5 MHz.
Alternately, for CR oscillation a resistor should be
connected. Leave this pin open if an external clock is
input to the OSC
1 pin.
Port
D
0 to D5
I/O
D port: I/O pins (CMOS three state) that can be
accessed in 1-bit units. Pins D
1 and D 2 are high current
pins that can accept influx currents of up to 15 mA.
R0
0 to R03
I/O
R0 port: Standard I/O pins (CMOS three state) that
can be accessed as a 4-bit unit.
R1
0 to R13
I/O
R1 port (HD404344R Series): I/O pins (CMOS three
state) that can be accessed as a 4-bit unit. Pins R1
0 to
R1
3 are high current pins that can accept influx currents
of up to 15 mA.
R1 port (HD404394 Series): I/O pins that can be
accessed as a 4-bit unit. Pins R1
0 to R12 are medium
voltage I/O pins (NMOS open drain). Also, pin R1
3 is a
standard voltage high current pin that can accept influx
currents of up to 15 mA.