1. 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
Explanation: In the I/O mode, the 8255 ports work as programmable I/O ports.
2. 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
Explanation: In BSR (Bit Set-Reset) Mode, port C can be used to set and reset its individual port bits.
3. 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
Explanation: In mode 0, any port can be used as input or output and output ports are latched.
4. The strobed input/output mode is another name of
a) mode 0
b) mode 1
c) mode 2
d) none
Explanation: In this mode, the handshaking signals control the input or output action of the specified port.
5.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
Explanation: If the value of the pin STB (Strobe Input) falls to low level, the input port is loaded into input latches.
6. The signal, SLCT in the direction of signal flow, OUT, indicates the selection of
a) Control word register
b) CPU
c) Printer
d) Ports
Explanation: This signal indicates that the printer is selected.
7. 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
Explanation: The pulse width of the signal must be more than 50 microseconds at the receiving terminal.
8.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
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. 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
Explanation: Handshaking signals maintain proper data flow and synchronization.
10. 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
Explanation: In mode 2 of 8255, a single 8-bit port is available i.e group A.