I/O Circuits and Electrical Characteristics
The following illustration is a simplified diagram of the input/output
circuitry of the bit I/O.
Output
Enable
IO0 ... IO31
33 Ω
10 kΩ
VCC
→
I
All pins provide overvoltage protection circuits by using suppressor
diodes. They short‑circuit external voltage spikes above 6 V to
ground.
I/O circuit
The bit I/O has TTL output/input levels with the following
characteristics.
Electrical characteristics
Parameter Value
Min. Max.
Input voltage High
Low
2.0 V
0 V
5.0 V
0.8 V
Output voltage High
Low
2.4 V
0 V
5.0 V
0.4 V
Output current ±10 mA
Input current
1)
500 μA
Power-up default All I/O channels are set to input
mode and to a defined logical
high level by the built-in 10 kΩ
pull-up resistors.
1)
The current direction is shown in the circuit diagram above.
s
Bit I/O
t
DS1103 Hardware Installation and Configuration November 2014
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