Fundamentals of Microprocessor and Microcontroller

1. S.N.D. College of Engineering and Research Center Department of Electrical Engineering Fundamentals of Microprocessor and Microcontroller UNIT-III Part A- 8255 Quiz Competition On By, Prof. Tambe S. S.

2. Q.1 The two widely used general-purpose programmable devices, can be compatible with ____ microprocessor A] Only 8085 B] Only 8086 C] Only 8051 D] Almost Any Microprocessor

3. Q.2 The signals exchanged between microprocessor and a peripheral prior to actual data transfer; these signals are__________ A] Control Signals B] Handshake Signals C] Status Signal D] Data Transfer Signals

4. Q.3 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 B] Chip Select Logic D] All of the above C] Handshake signals and interrupt logic

5. Q.4 8255 has ________ I/O pins A] 40 B] 16 D] 28 C] 24

6. Q.5 If chip select logic of 8255 is connected to the A7 line through NOT gate and A0 and A1 of 8255 connected to the A0 and A1 of the system address bus, then assuming A6 to A2 at logic 0, what will be the address of Port C ? A] 8020H B] 8002H D] 28H C] 82H

7. Q.6 I/O function or bit set/reset function of 8255 are classified by the_____ bit of control word register A] D7 B] D0 D] D6 and D5 C] D6

8. Q.7 Which of the following statements are true A] Port C operates in the Bit set/reset mode B] BSR control word does not affect the function of Port A and B D] Both A and B are True C] Both A and B are Wrong

9. Q.8 In which of the following modes, ports does not have handshake or interrupt capability A] Mode 1 B] Mode 0 D] All of the above C] Mode 2

10. Q.9 Identify the Mode 0 control word to configure port A and port Cu as output ports and port B and port CL as input ports. A] 83 B] 82 D] 80 C] 81

11. Q.10 8255 is interfaced with 8085 in memory mapped I/O scheme. If this 8255 chip is selected when A15 line is high and A0 and A1 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 B] 8003H D] 82H C] 8383H

12. Q.11 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 B] MVI A, 80H OUT CWR D] MVI A, 80H LDA 4003H C] MVI A, 80H STA 4003H

13. Q.12 If the 8255 system is reset then: A] It clears the control register B] Sets all the ports in the output mode D] Only A and C. C] Sets all the ports in the input mode

14. Q.13 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 B] 81H C] 82H D] 83H.

15. Q.14 To set/reset bits in port C, a control word is written in to A] Port C B] Control word register D] Can’t be predicted C] Both A and B

16. Q.15 A BSR Control word affects A] Only Port A B] Only Port B D] All of above ports C] Only Port C

17. Q.16 In mode 0 A] 8 bits of Port A, B ,Cu and CL can be programmed as either input or output B] Ports A and B are used as simple 8-bit I/O ports D] Both B and C C] Port C as two 4-bit ports

18. Q.17 In mode 1 A] Two ports A and B function as 8-bit I/O ports B] Input data are latched C] Output data are latched D] All of above

19. Q.18 The bits of Port C used for handshaking when ports A is configured as input port in mode1 are: A] PC0, PC1 and PC3 B] PC4, PC5 and PC6 C] PC3, PC4 and PC5 D] PC2, PC1 and PC0

20. Q.19 In 8255 mode1, Which signal generated by a peripheral device to indicate that it has transmitted a byte of data? A] STB B] IBF C] INTR D] INTE

21. Q.20 A control word to set up Port A as input and Port B as output in Mode 1 is A] B4 B] C4 C] 4B D] Can’t be predicted

22. Q.21 8255 has ______parallel ports A] Three 4-bit B] Two 8- bit C] Two 4 bit D] Three 8- bit

23. Q.22 8255 has _____ I/O modes A] 3 B] 2 C] 1 D] 4

24. Q.23 A high on _____ line causes all 24 lines of three 8 –bit ports to be in the input mode. A] WR B] RESET C] GND D] RD

25. Q.24 If______, the control word is taken as a I/O mode definition word A] D7 = 1 B] D7 = 0 C] D0 = 1 D] D0 = 0

26. Q.25 If______, the control word is taken as a Bit set/reset word A] D7 = 1 B] D7 = 0 C] D0 = 1 D] D0 = 0

27. Q.26 On activation of _____, the 8255 loads data from the input port lines into the input buffer of that port. A] STB B] IBF C] OBF D] None of the above

28. Q.27 8255 sets INTR when STB, IBF and INTE for input control signals are ________ respectively A] 1, 0 and 1 B] 1, 1 and 0 C] 1, 1 and 1 D] 0, 1 and 1

29. Q.28 Which of the following port can be programmed in Mode 0,1 and 2 ? A] Port A B] Port B C] Port C D] Both A and B

30. Q.29 _____ is a general purpose programmable I/O device used for parallel data transfer. A] 8254 B] 8255 C] 0808 D] 8051

31. Q.30 Mode 1 of 8255 I/O mode is: A] Input/output with handshake B] Simple input/output C] Both A and B D] None of these

32. Q.31 • Which of the following mode of 8255 is Strobed Bi-directional I/O? A] Mode 0 B] Mode 2 C] Mode 1 D] BSR Mode

33. Q.32 What is the status of port bit if it is configured as an output port? A] 1 B] 11 C] 0 D] 00

34. Q.33 • What is the status of A1, A0 during an input read or output write operation with port B? A] 00 B] 11 C] 10 D] 01

35. Q.34 • Port A and lower nibble of Port C come under ____ Group. A] A B] B C] C D] None of these

36. Q.35 • Which of the following port can be programmed nibble wise (separately)? A] Port A B] Port B C] Port C D] None of these

37. Q.36 • What type of control signal is IBF in mode 1? A] Input B] Output C] Input/output D] None of these

38. Q.37 • What type of control signal is INTR in mode 1? A] Input B] Output C] Input/output D] None of these

39. Q.38 • What is the size of I/O ports in 8255 ? A] 8 bits B] 16 bits C] 4 bits D] 1 bit

40. Q.39 • The status of A1 –A0 to select the CWR must be A] 00 B] 01 C] 10 D] 11

41. Q.40 • In 8255 RESET pin is used for ______. A] resetting CWR and 3 ports B] resetting CWR C] resetting 8085 D] resetting 3 ports

42. Q.41 • In 8255 _____ are 8 bit bi-directional I/O pins used to send data to peripheral or to read data from peripheral. A] PA0 –PA7 B] PB0 –PB7 C] PC0 – PC7 D] All of these

43. Q.42 • Group A signals of 8255 consists of _______ A] Port A and Port B B] Port B and Port Cupper C] Port Cu and Port A D] Port A, B and C

44. Q.43 • In BSR mode what will be bit pattern of CWR for setting PC3 bit A] 0xxx0111 B] 011xxx11 C] 1xxx0111 D] 0xxx0110

45. Q.44 • BSR mode in 8255 is for A] Port A B] Port B C] Port C D] All of these

46. Q.45 • The control word to set bit 4 of port C is_______. A] 09H B] 04H C] 90H D] 40H