Engineering Questions with Answers - Multiple Choice Questions

MCQs on Modes of Operation of 8255

1 - Question

In the I/O mode, the 8255 ports work as
a) reset pins
b) set pins
c) programmable I/O ports
d) only output ports

View Answer

Answer: c
Explanation: In the I/O mode, the 8255 ports work as programmable I/O ports.




2 - Question

In BSR mode, only port C can be used to
a) set individual ports
b) reset individual ports
c) set and reset individual ports
d) programmable I/O ports

View Answer

Answer: c
Explanation: In BSR (Bit Set-Reset) Mode, port C can be used to set and reset its individual port bits.




3 - Question

The feature of mode 0 is
a) any port can be used as input or output
b) output ports are latched
c) maximum of 4 ports are available
d) all of the mentioned

View Answer

Answer: d
Explanation: In mode 0, any port can be used as input or output and output ports are latched.




4 - Question

The strobed input/output mode is another name of
a) mode 0
b) mode 1
c) mode 2
d) none

View Answer

Answer: b
Explanation: In this mode, the handshaking signals control the input or output action of the specified port.




5 - Question

If the value of the pin STB (Strobe Input) falls to low level, then
a) input port is loaded into input latches
b) input port is loaded into output latches
c) output port is loaded into input latches
d) output port is loaded into output latches

View Answer

Answer: a
Explanation: If the value of the pin STB (Strobe Input) falls to low level, the input port is loaded into input latches.




6 - Question

The signal, SLCT in the direction of signal flow, OUT, indicates the selection of
a) Control word register
b) CPU
c) Printer
d) Ports

View Answer

Answer: c
Explanation: This signal indicates that the printer is selected.




7 - Question

The pulse width of the signal INIT at the receiving terminal must be more than
a) 10 microseconds
b) 20 microseconds
c) 40 microseconds
d) 50 microseconds

View Answer

Answer: d
Explanation: The pulse width of the signal must be more than 50microseconds at the receiving terminal.




8 - Question

The level of the signal ERROR(active low) becomes ‘low’ when the printer is in
a) Paper end state
b) Offline state
c) Error state
d) All of the mentioned

View Answer

Answer: d
Explanation: The level of the signal ERROR(active low) becomes ‘low’ when the printer is in the Paper end state, Offline state and Error state.




9 - Question

The signals that are provided to maintain proper data flow and synchronization between the data transmitter and receiver are
a) handshaking signals
b) control signals
c) input signals
d) none

View Answer

Answer: a
Explanation: Handshaking signals maintain proper data flow and synchronization.




10 - Question

The feature of mode 2 of 8255 is
a) single 8-bit port is available
b) both inputs and outputs are latched
c) port C is used for generating handshake signals
d) all of the mentioned

View Answer

Answer: d
Explanation: In mode 2 of 8255, a single 8-bit port is available i.e group A.

Get weekly updates about new MCQs and other posts by joining 18000+ community of active learners