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MCQ | 8255 PPI (Programmable peripheral interface)

Multiple choice questions and answers (MCQ) on the 8255 programmable peripheral interface (PPI) with 4 choices, correct answer and explanation.
Submitted by Monika Sharma, on February 10, 2021

Question 1: How many pins does the 8255 PPI IC contains?

1. 24
2. 20
3. 32
4. 40

Answer: d. 40

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Question 2: In which mode do all the Ports of the 8255 PPI work as Input-Output units for data transfer?

1. BSR mode
2. Mode 0 of I/O mode
3. Mode 1 of I/O mode
4. Mode 2 of I/O mode

Answer: b. Mode 0 of I/O mode

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 Question 3: Which of the following pins are responsible for handling the on the Read Write control logic unit of the 8255 PPI?

1. CS'
2. RD'
3. WR'
4. ALL of the above

Answer: d. All of the above

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Question 4: In which of the following modes is the 8255 PPI capable of transferring data while handshaking with the interfaced device?

1. BSR mode
2. Mode 0 of I/O mode
3. Mode 1 of I/O mode
4. Mode 2 of I/O mode

Answer: c. Mode 1 of I/O mode

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Question 5: How many bits of data can be transferred between the 8255 PPI and the interfaced device at a time? or What is the size of internal bus of the 8255 PPI?

1. 16 bits
2. 12 bits
3. 8 bits
4. None of the above

Answer: c. 8 bits

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Question 6: Which port of the 8255 PPI is capable of performing the handshaking function with the interfaced devices?

1. Port A
2. Port B
3. Port C
4. All of the above

Answer: c. Port C

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Question 7: In which of the following modes of the 8255 PPI, only port C is taken into consideration?

1. BSR mode
2. Mode 0 of I/O mode
3. Mode 1 of I/O mode
4. Mode 2 of I/O mode

Answer: a. BSR mode

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Question 8: In mode 2 of I/O mode, which of the following ports are capable of transferring the data in both the directions?

1. Port A
2. Port B
3. Port C
4. All of the above

Answer: a. Port A

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Question 9: In which of the following modes we do not consider the D6, D5 and D4 bits of the control word?

1. BSR mode
2. Mode 0 of I/O mode
3. Mode 1 of I/O mode
4. Mode 2 of I/O mode

Answer: a. BSR mode

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Question 10: How many data lines in total are there in the 8255 PPI IC?

1. 8 data lines
2. 32 data lines
3. 24 data lines
4. None of the above

Answer: c. 24 data lines

Question 11: PPI 8255 is a general purpose programmable I/O device designed to interface the CPU with its outside world such as ADC, DAC, keyboard etc.

1. True
2. False

Answer: a. True

Explanation:

PPI 8255 is a general purpose programmable I/O device which is specifically designed to interface the CPU with its outside world such as ADC, DAC, keyboard etc.

Question 12: During process a data bus buffer has controlled using,

1. Control word register
2. Data bus
3. R/W control logic
4. None of these

Answer: b. Data bus

Explanation:

During process a data bus buffer has controlled using read/write control logic.

Question 13: The 8255 ports works in the I/O mode,

1. Programmable I/O ports
2. Set pins
3. Reset pins
4. None of these

Answer: a. Programmable I/O ports

Explanation:

The 8255 ports work in the I/O mode as programmable I/O ports.

Question 14: PPI 8255 consists of three 8-bit bidirectional I/O ports,

1. PORT A,
2. PORT B
3. PORT C
4. All of these

Answer: d. All of these

Explanation:

PPI 8255 consists of three 8-bit bidirectional I/O ports as PORT A, PORT B, and PORT C.

Question 15: PPI 8255 consists of 40 pins and operates in ... regulated power supply,

1. +5V
2. +15V
3. +5V
4. None of these

Answer: a. +5V

Explanation:

PPI 8255 consists of 40 pins and operates in +5V regulated power supply.

Question 16: Strobed input/output mode is also known as -

1. Mode 0
2. Mode 1
3. Mode 2
4. None of these

Answer: b. Mode 1

Explanation:

In this mode, the input or output operation of the specified port is controlled by handshaking signals.

Question 17: The strobed input/output mode is another name of,

1. Mode 0
2. Mode 1
3. Mode 2
4. None of these

Answer: b. Mode 1

Explanation:

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

Question 18: The pulse width of the INIT signal at the receiving terminal must be greater than ... that of the receiving terminal –

1. 10 microseconds
2. 50 microseconds
3. 40 microseconds
4. 20 microseconds

Answer: b. 50 microseconds

Explanation:

The pulse width of a signal at the receiving terminal must be more than 50 microseconds.

Question 19: The feature of mode 2 of 8255 is,

1. Both inputs and outputs are latched
2. Port C is used for generating handshake signals
3. Single 8-bit port is available
4. All of these

Answer: d. All of these

Explanation:

A single 8-bit port is available in mode 2 of 8255, i.e., group A.

Question 20: The port which is used in mode 1 or mode 2 for the generation of handshake lines is,

1. Port A
2. Port B
3. Port C Upper
4. Port C Lower

Answer: d. Port C Lower

Explanation:

The upper Port C is used for the generation of mode 1 or mode 2 handshake lines.

Question 21: The pin that clears the control word register of 8255 when enabled is,

1. RESET
2. SET
3. CLEAR
4. CLK

Answer: a. RESET

Explanation:

If the reset pin is allowed, then the register of control words is cleared.

Question 22: The signals that are provided to maintain proper data flow and synchronization between the data transmitter and receiver are –

1. Handshaking signals
2. Control signals
3. Input signals
4. None of these

Answer: a. Handshaking signals

Explanation:

Handshaking signals preserve proper flow and synchronization of information. In order to create a valid link between two stations, signals are transmitted back and forth via a communications network. In an RS-232 serial transmission, a "hardware handshake" utilizes dedicated wires such as request-to-send (RTS) and clear-to-send (CTS) lines.

Question 23: From pin PA0 – PA7 are the part of -

1. Pins of port A
2. Pins of port B
3. Pins of port C
4. None of these

Answer: a. Pins of port A

Explanation:

There are 24 input/output pins for the 8255. These are split into three ports that are 8-bit (A, B, C). It is possible to use Port A and Port B as 8-bit input/output ports. Pins of port A consist pins from pin PA0 – PA7.Port C can be used either as an 8-bit input/output port or as two 4-bit input/output ports or for ports A and B to create handshake signals.

Question 24: In the pin diagram of PIP 8255, CS stands for Chip select,

1. True
2. False

Answer: a. True

Explanation:

In the pin diagram of PIP 8255, CS stands for Chip select. Chip selection (CS) or slave selection (SS) is the name of a digital electronics control line used to select one (or a set) of integrated circuits (commonly referred to as 'chips') out of many connected to the same device bus, typically using three-state logic.

Question 25: If MSB of control word (D7) is 0, PPI works in BSR mode.

1. True
2. False

Answer: a. True

Explanation:

If MSB of control word (D7) is 0, PPI works in BSR mode.