Which out of the four ports of 8051 needs a pull-up resistor for using it is as an input or an output port?
A. PORT 0
B. PORT 1
C. PORT 2
D. PORT 3
Answer:A
Which out of the four ports of 8051 needs a pull-up resistor for using it is as an input or an output port?
A. PORT 0 B. PORT 1 C. PORT 2 D. PORT 3
Explanation: These pins are the open drain pins of the controller which means it needs a pull-up resistor for using it as an input or an output ports.