Microprocessors

Peripheral Interfacing — Practice MCQs for CCAT

10 Questions Section C: Hardware Microprocessors

Practice 10 Peripheral Interfacing multiple-choice questions designed for CDAC CCAT exam preparation. Click "Show Answer" to reveal the correct option with detailed explanation.

Q1.
8255 is:
ATimer
BPPI (Programmable Peripheral Interface)
CUART
DDMA controller
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Correct Answer: B — PPI (Programmable Peripheral Interface)

8255 is PPI - provides 3 ports for parallel I/O.

Q2.
8255 has how many ports?
A1
B2
C3
D4
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Correct Answer: C — 3

8255 has 3 ports: Port A, Port B, Port C.

Q3.
8254 is:
APPI
BProgrammable Interval Timer
CUART
DMemory
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Correct Answer: B — Programmable Interval Timer

8254 is a programmable timer/counter.

Q4.
8259 is:
ATimer
BPPI
CProgrammable Interrupt Controller
DUART
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Correct Answer: C — Programmable Interrupt Controller

8259 PIC manages hardware interrupts.

Q5.
8257 is:
ATimer
BDMA Controller
CPPI
DUART
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Correct Answer: B — DMA Controller

8257 is a DMA controller for direct memory access.

Q6.
8251 is:
ATimer
BPPI
CUSART
DDMA
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Correct Answer: C — USART

8251 USART handles serial communication.

Q7.
Maximum 8259 PICs cascaded:
A4
B8
C9 (1 master + 8 slaves)
D16
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Correct Answer: C — 9 (1 master + 8 slaves)

8259 can cascade: 1 master + 8 slaves = 64 interrupt levels.

Q8.
8255 Mode 0 is:
AStrobed I/O
BSimple I/O (no handshaking)
CBidirectional
DCounter mode
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Correct Answer: B — Simple I/O (no handshaking)

Mode 0: Basic I/O without handshaking.

Q9.
8254 has how many counters?
A1
B2
C3
D4
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Correct Answer: C — 3

8254 has 3 independent 16-bit counters.

Q10.
DMA advantage:
AUses more CPU
BTransfers data without CPU
CSlower than programmed I/O
DNo advantage
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Correct Answer: B — Transfers data without CPU

DMA transfers data directly between I/O and memory without CPU.