By, Prof. Tambe S. S. S.N.D. College of Engineering and Research Center Department of Electrical Engineering

The two widely used general-purpose programmable devices, can be compatible with ____ microprocessor A] Only 8085 D] Almost Any Microprocessor C] Only 8051 B] Only 8086

The signals exchanged between microprocessor and a peripheral prior to actual data transfer; these signals are__________ A] Control Signals D] Data Transfer Signals C] Status Signal B] Handshake Signals

A programmable I/O devices likely to have which of the following devices: A] A control register in which the MPU can write an instruction D] All of the above C] Handshake signals and interrupt logic B] Chip Select Logic

8255 has ________ I/O pins 8255 has ________ I/O pins A] 40 D] 28 C] 24 B] 16

If chip select logic of 8255 is connected to the A 7 line through NOT gate and A 0 and A 1 of 8255 connected to the A 0 and A 1 of the system address bus, then assuming A 6 to A 2 at logic 0, what will be the address of Port C ? A] 8020H D] 28H C] 82H B] 8002H

I/O function or bit set/reset function of 8255 are classified by the_____ bit of control word register A] D7 D] D6 and D5 C] D6 B] D0

Which of the following statements are true A] Port C operates in the Bit set/reset mode D] Both A and B are True C] Both A and B are Wrong B] BSR control word does not affect the function of Port A and B

In which of the following modes, ports does not have handshake or interrupt capability A] Mode 1 D] All of the above C] Mode 2 B] Mode 0

Identify the Mode 0 control word to configure port A and port C u as output ports and port B and port C L as input ports. A] 83 D] 80 C] 81 B] 82

8255 is interfaced with 8085 in memory mapped I/O scheme. If this 8255 chip is selected when A 15 line is high and A 0 and A 1 lines are used to select Port A, B, C and Control Word register then, assuming all don’t care address lines at logic 0, the address of Control Word register is: A] 83H D] 82H C] 8383H B] 8003H

If 8255 is interfaced in Memory mapped I/O scheme. The Addresses of Port A,B,C and CWR are 4000H,4001H,4002H and 4003H respectively, then which of the following instructions will configure the all the ports as output port in Mode0 ? A] MVI A, 83H STA 4003H A] MVI A, 83H STA 4003H D] MVI A, 80H LDA 4003H D] MVI A, 80H LDA 4003H C] MVI A, 80H STA 4003H C] MVI A, 80H STA 4003H B] MVI A, 80H OUT CWR B] MVI A, 80H OUT CWR

If the 8255 system is reset then: A] It clears the control register D] Only A and C. C] Sets all the ports in the input mode B] Sets all the ports in the output mode

The addresses for Port A,B,C and CWR are 80H,81H, 82H and 83H respectively. MVI A, 80H OUT 83H XRA A OUT 82H ORI 0FH OUT 83H What will be the content of Port C after execution of above instructions ? The addresses for Port A,B,C and CWR are 80H,81H, 82H and 83H respectively. MVI A, 80H OUT 83H XRA A OUT 82H ORI 0FH OUT 83H What will be the content of Port C after execution of above instructions ? A] 80H D] 83H. C] 82H B] 81H

To set/reset bits in port C, a control word is written in to A] Port C D] Can’t be predicted C] Both A and B B] Control word register

A BSR Control word affects A] Only Port A D] All of above ports C] Only Port C B] Only Port B

In mode 0 A] 8 bits of Port A, B,C u and C L can be programmed as either input or output D] Both B and C C] Port C as two 4-bit ports B] Ports A and B are used as simple 8-bit I/O ports

In mode 1 A] Two ports A and B function as 8-bit I/O ports D] All of above C] Output data are latched B] Input data are latched

The bits of Port C used for handshaking when ports A is configured as input port in mode1 are: A] PC 0, PC 1 and PC 3 D] PC 2, PC 1 and PC 0 C] PC 3, PC 4 and PC 5 B] PC 4, PC 5 and PC 6

In 8255 mode1, Which signal generated by a peripheral device to indicate that it has transmitted a byte of data? D] INTE C] INTR B] IBF A] STB

A control word to set up Port A as input and Port B as output in Mode 1 is D] Can’t be predicted C] 4B B] C4 A] B4

8255 has ______parallel ports D] Three 8- bit C] Two 4 bit B] Two 8- bit A] Three 4-bit

8255 has _____ I/O modes D] 4 C] 1 B] 2 A] 3

A high on _____ line causes all 24 lines of three 8 –bit ports to be in the input mode. D] RD C] GND B] RESET A] WR

If______, the control word is taken as a I/O mode definition word D] D 0 = 0 C] D 0 = 1 B] D 7 = 0 A] D 7 = 1

If______, the control word is taken as a Bit set/reset word D] D 0 = 0 C] D 0 = 1 B] D 7 = 0 A] D 7 = 1

On activation of _____, the 8255 loads data from the input port lines into the input buffer of that port. D] None of the above C] OBF B] IBF A] STB

8255 sets INTR when STB, IBF and INTE for input control signals are ________ respectively D] 0, 1 and 1 C] 1, 1 and 1 B] 1, 1 and 0 A] 1, 0 and 1

Which of the following port can be programmed in Mode 0,1 and 2 ? D] Both A and B C] Port C B] Port B A] Port A

_____ is a general purpose programmable I/O device used for parallel data transfer. D] 8051 C] 0808 B] 8255 A] 8254

Mode 1 of 8255 I/O mode is: D] None of these C] Both A and B B] Simple input/output A] Input/output with handshake

Which of the following mode of 8255 is Strobed Bi- directional I/O? D] BSR Mode C] Mode 1 B] Mode 2 A] Mode 0

What is the status of port bit if it is configured as an output port? D] 00 C] 0 B] 11 A] 1

What is the status of A1, A0 during an input read or output write operation with port B? D] 01 C] 10 B] 11 A] 00

Port A and lower nibble of Port C come under ____ Group. D] None of these C] C B] B A] A

Which of the following port can be programmed nibble wise (separately)? D] None of these C] Port C B] Port B A] Port A

What type of control signal is IBF in mode 1? D] None of these C] Input/output B] Output A] Input

What type of control signal is INTR in mode 1? D] None of these C] Input/output B] Output A] Input

What is the size of I/O ports in 8255 ? D] 1 bit C] 4 bits B] 16 bits A] 8 bits

The status of A1 –A0 to select the CWR must be D] 11 C] 10 B] 01 A] 00

In 8255 RESET pin is used for ______. D] resetting 3 ports C] resetting 8085 B] resetting CWR A] resetting CWR and 3 ports

In 8255 _____ are 8 bit bi-directional I/O pins used to send data to peripheral or to read data from peripheral. D] All of these C] PC0 – PC7 B] PB0 –PB7 A] PA0 –PA7

Group A signals of 8255 consists of _______ D] Port A, B and C C] Port Cu and Port A B] Port B and Port Cupper A] Port A and Port B

In BSR mode what will be bit pattern of CWR for setting PC3 bit D] 0xxx0110 C] 1xxx0111 B] 011xxx11 A] 0xxx0111

BSR mode in 8255 is for D] All of these C] Port C B] Port B A] Port A

The control word to set bit 4 of port C is_______. D] 40H C] 90H B] 04H A] 09H