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Micro-controller 8051-VIVA QUESTION-I
  • The 8051 micro-controller has - 128 bytes of RAM
  • How many serial port are present in 8051 micro-controller?-1
  • The Program status register are used as Flag Register. 
  • MOV A, @ R1 will-copy the contents of memory whose address is in R1 to the accumulator
  • ADD R4, A are invalid because A will destination position always in arithmetic operation.
  • Data transfer from I/O to external data memory can only be done with the MOV command-False
  • Registers R0-R7 are all ………bits wide? - 8
  • The 8051 has only one subtraction instruction –SUBB
  • A quartz crystal oscillator is connected to inputs pin no 18 and 19. 
  • Which of the following is illegal?  (a) ADD  R3,#50 (b) ADD A, #50 (c) MOV R7, #50
  • ADD R2, #12 H are invalid because A will destination position always in arithmetic operation. 
  • DJNZ refers to? - decrement and jump if not zero
  • WAP to find 2’s complement of a number- CPL A +1 
  • Registers ACC and B are ----bits wide? - 8 
  • SWAP A-It swap the lower nibble and the higher nibble & works only on the accumulator 
  • The total amount of external code memory that can be interfaced to the 8051 is: - 64 K 
  • A micro-controller has which of the following devices on chip?-RAM, ROM, I/O Devices 
  • The 8051 has ________ 16-bit counter/timers.- 2   
  • The command will copy the accumulator to the location whose address is 23H:-MOV 23H, A
  • Which of the following is illegal?(a) MOV R3, #50 (b) MOV R1, #50 (c) MOV R8, #50
  •  JNZ refers to? - Jump if accumulator is not zero
  • The 8-bit address bus allows access to an address range of: - 00 to FFH 
  •  The 8051 micro-controller has - 4 K bytes on chip ROM  
  • The address space of the 8051 is divided into four distinct areas: internal data, external data, internal code, and external code. - True   
  • The 8051 has ________ parallel I/O ports. - 4
  • Registers DPTR and PC are ----bits wide? - 16 
  • Assembly Language Program is a series of statement or Lines. 
  • Assembly language is Low Level Language. 
  • MOV A, #7F2H – illegal 7F2H>8 Bits (FF H) 
  • MOV A, #F9H—This is not correct,0 should be between # and F.
  • DA –decimal adjust for addition & DA only works after ADD, ADDC. 
  • MOV A, #5 H- Value in Accumulator will be A=05 H
  • How many I/O pins are in 8051 micro-controller? - 32
  • How many interrupt sources are in 8051 micro-controller? - 6 
  • MOVX refers to? - Transfer data between external memory and Register A 
  • Name of a 8-bit micro-controller—Intel 8051, Motorola 6811, Zilog Z8
  • 8051 has 2 Timers, 1 Serial Port, 6 interrupt sources
  • AT89C51 is manufactured by Atmel Corporation.
  • 8052 has 256 Bytes of RAM, 3 Timers and 8 Interrupts sources.
  • Registers are used to store information temporarily.
  • The most widely used registers are A, B, R0-R7, DPTR and PC.
  • Program Counter is 16 bit wide.
  • 8051 micro-controller has only one data types- 8 bits
  • The Movement of data between Rn register is invalid MOV R4, R7 is invalid. 
  • Register Bank 0 is default when 8051 is powered up
  • The source and destination registers must match in size MOV DPTR, A will give an error. 
  • The immediate data must be preceded by the pound sign “#”.  
  • Program Counter The PC points to the address of the next instruction to be executed. 
  • The Data Types can be Positive or Negative. 
  • JZ refers to? - Jump if A=0   
  • Which is correct regarding DPTR?-Data Pointer, 16 bit
  • Which commands will copy the contents of location 4H to the accumulator?  MOV A, 04H


  1. Anonymous13 July, 2013

    thank u...

  2. nice job, but you can add more questions and difficulty level can be increased.

  3. nice thank u