M38203M4 Datasheet, PDF (100/344 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.1 I/O pins
(5) Termination of unused pins
Table 2.1.4 shows termination of unused pins.
Table 2.1.4 Termination of unused pins
Pins
Terminations
P20–P27
P41/φ
P44/RxD
P45/TxD
P46/SCLK1
P47/SRDY1
P50/SIN2
P51/SOUT2
P52/SCLK2
P53/SRDY2
ŒAfter set for the input mode and put the built-in pull-up resistor in the ON state,
open.^V1
Set for the output mode and open at “L” or “H.”^V2
P54/CNTR0
P55/CNTR1
P56/TOUT
P61/RTP1
P70/XCOUT
P71/XCIN
P00/SEG24–P07/SEG31 ŒAfter set for the input mode and put the built-in pull-down resistor in the ON
P10/SEG32–P17/SEG39 state, open.^V1
Set for the output mode and open at “L” or “H.”^V2
P40
Connect each pin to VCC or VSS through each resistor of 1 kΩ to 10 kΩ.
P42/INT0
P43/INT1
P57/INT2
P60/INT3/RTP0
ŒAfter disabling INT interrupts, set for the input mode, and put the built-in pull-up
resistor in the ON state, open.^V1
Set for the output mode and open at “L” or “H.”^V2
VL1–VL3
Connect to VSS level
COM0–COM3
SEG0–SEG15
Open
P30/SEG16–P37/SEG23 Put the built-in pull-down resistor in the ON state, open.^V1
V1 After reset and before the built-in pull-up (pull-down) resistor is put in the ON state by software,
the built-in pull-up (pull-down) resistor is in the OFF state. Because of this, the potential at these
pins are “undefined” and the power source current may increase. Since the direction register setup
may be changed for the output mode because of a program runaway or noise, set direction
register for the input mode periodically. And make the length of wiring which is connected I/O ports
within 2 cm.
V2 After reset and before I/O ports are switched for the output mode by software, I/O ports are set
for the input mode. Because of this, the potential at these pins are “undefined” and the power
source current may increase in the input mode. Since the direction register setup may be changed
for the input mode because of a program runaway or noise, set direction register for the output
mode periodically. And make the length of wiring which is connected I/O ports within 2 cm.
2–14
3820 GROUP USER’S MANUAL