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APPLICATION
2.1 I/O pins
3822 GROUP USER’S MANUAL
2–14
(5) Termination of unused pins
Table 2.1.4 shows termination of unused pins.
Terminations
Pins
Table 2.1.4 Termination of unused pins
P20–P27
P41/
φ
P44/RxD
P45/TxD
P46/SCLK
P47/SRDY
P52/RTP0
P53/RTP1
P54/CNTR0
P55/CNTR1
P56/TOUT
P57/ADT
P60/AN0–P67/AN7
P70/XCOUT
P71/XCIN
P00/SEG16–P07/SEG23
P10/SEG24–P17/SEG31
P40
P42/INT0
P43/INT1
P50/INT2
P51/INT3
VL1–VL3
COM0–COM3
SEG0–SEG11
P34/SEG12–P37/SEG15
Connect each pin to VCC or VSS through each resistor of 1k
to 10 k .
After 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
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.
After set for the input mode and put the built-in pull-down resistor in the ON
state, open.V1
Set for the output mode and open at “L” or “H”.V2
After disabling INT interrupts, set for the input mode, and put the pull-up built-
in resistor in the ON state, open.V1
Set for the output mode and open at “L” or “H”.V2
Connect to VSS level
Open