MICRO PROCESSOR AND ITS APPLICATIONS

MICRO PROCESSOR AND ITS APPLICATIONS

1.Define Microprocessor?
Microprocessor is a multipurpose, programmable, clock-driven, register based
electronic device that reads binary instructions from a storage device called
memory, accepts binary data as input and processes data according to those
instructions, and provides as output.

2. What is Hardware and Software?
The physical components of the system i.e. computer are called Hardware.
Group of programs is called software.

3. Why the microprocessor is viewed as a programmable Device?
Microprocessor is programmable because it can be instructed to perform given
tasks within its capability. Microprocessor is designed to understand and execute
many binary instructions.

4. What is Central processing Unit ( CPU ) ? And Write the use of it.
CPU is a heart of the computer. Central processing Unit controls the operation
of the computer. In a microcomputer the CPU is a microprocessor. The CPU
fetches binary coded instructions from memory, decodes the instructions into a
series of simple actions and carries out these actions in a sequence of steps.

5. What is a chip?
A chip is also called an integrated circuit. Generally it is a small, thin piece
of silicon onto which the transistors making up the microprocessor have been
etched. A chip might be as large as an inch on a side and can contain tens of
millions of transistors. Simpler processors might consist of a few thousand
transistors etched onto a chip just a few millimeters square.

6. What is System Bus?
The System bus is a communication path between the microprocessor and
peripherals. It is nothing but a group of wires to carry bits.

7. What is Address Bus?
The address bus consists of 16, 20, 24 or 32 parallel signal lines. On these
lines the CPU sends out the address of the memory location that is to be written to
or read from. The number of address lines determines the number of memory
locations that the CPU can address. If the CPU has N address lines, then it can
directly address 2N memory locations. Simply, we can say that Address Bus is
used to carry the address.

8. What is Data Bus?
The data bus consists of 8, 16, or 32 parallel signal lines. The data bus lines
are bidirectional. This means that the CPU can read data in from memory or from
a port on these lines, or it can send data out to memory or to a port on these lines.
Simply we can say that data bus is used to carry the data.

9. What is Assembly Language?
A medium of communication with a computer in which programs are
written in mnemonics. Binary instructions are given abbreviated names called
mnemonics, which form the assembly language for a given processor.

10. What is Machine Language?
The binary medium of communication with a computer through a designed
set of instructions specific to each computer.

11. What is Bit-Slice processor?
For some Applications , general purpose CPUs such as the 8080 and 6800
are not fast enough or do not have suitable instruction sets. For these
applications ,several manufacturers produce devices which can be used to build
the custom CPU. This family includes 4 bit ALUs, multiplexers, sequencers and
other parts needed for custom building a CPU. The term slice comes from the
fact that these parts can be connected in parallel to work with 8 bit words, 16-
bit words, or 32 bit words.

12. What is microcontroller?
Microcontroller is a Device that includes microprocessor, memory and
I/O signal lines on a single chip, fabricated using VLSI technology.

13. List the main applications of 8 bit microprocessors?
8 bit microprocessors is used in a variety of applications such as
appliances, automobiles, industrial process and control applications.

14. Write the uses of microprocessors in Medical Instrumentation field?
Patient Monitoring in Intensive Care Unit, Pathological Analysis and the
measurement of parameters like blood pressure and temperature.

15. Define Real Time Systems :
Real Time Systems are those in which timeliness is as important as the
correctness of the outputs, although this does not mean that they have to be “fast
systems”.

16. List the limitations of 8 bit microprocessor:
• Lower Execution Speed
• It can address less memory size
• Few instructions are available

17. What do you mean ‘ Data Width’?
Data Width is the width of the ALU. An 8 bit ALU can add / subtract/
multiply etc.. two 8 bit numbers . In many cases, the external data bus is the
same width as the ALU, but not always. The 8088 had a 16 bit ALU and 8 bit
bus , while the modern Pentiums fetch data 64 bits at a time for their 32 bit
ALUs.

18. Draw and specify the complete bit configuration of 8085 flag Register?
D7 D6 D5 D4 D3 D2 D1 D0
S Z AC P CY
S- Sign Flag . If D7 =1 , then sign flag is set, otherwise rest.
Z-Zero flag. If ALU operation results in zero, then this flag is set,
Otherwise it is reset.
AC-Auxilliary flag. In an arithmetic operation ,when a carry is generated
by digit D3 and passed on to digit D4, the AC flag is set.
Otherwise it is reset.
P-Parity Flag. If the result of an arithmetic or logic operation has an even
number of 1’s then this flag is set. Otherwise it is reset.
CY-Carry Flag. If an arithmetic operation results in a carry, the carry flag
is set. Otherwise it is reset.

19. List the four operations commonly performed by MPU( Micro processing
Unit)?
• Memory Read : Reads data (or instructions) from memory.
• Memory Write: Writes Data (or instructions) into memory.
• I/O Read: Accepts data from input devices.
• I/O Write: Sends data to output devices.

20. Write about RST pins in 8085?
In 8085 ,three RST pins are available, such as RST 7.5 ,RST 6.5 , RST
5.5. RST represents Restart Interrupts. These are vectored interrupts that
transfer the program control to specific memory locations. They have higher
priorities than the INTR interrupt. Among these three, the priority order is
7.5,6.5,5.5.

21. List the control and status signals available in 8085.
ALE , RD, WR, IO/M, S1, S2
ALE-Address Latch Enable
RD – Read Control Signal
WR – Write Control Signal
IO/M - To specify I/O or memory operation
S1 , S2 – Status signals

22. What are the limitations of 8085 MPU?
(i) The lower order address bus of the 8085 microprocessor is multiplexed
(time shared) with the data bus. The buses need to be demultiplexed.
(ii) Appropriate control signals need to be generated to interface memory
and I/O with the 8085.

23. Compare the 8 bit microprocessors 8080A and 8085.
8080A is the predecessor of 8085. 8085 has the instruction set of
8080A plus some additional ones. Program written for 8080A will be executed
by 8085. 8085 and 8080A are not pin compatible. Both require a +5V power
supply.

24. Define Register Relative Addressing Mode.
Register Relative Addressing Mode : The Effective Address is Calculated
by the sum of 8- or 16 bit displacement and the contents of a base Register or an
index Register.
E.A. = content of(BX or BP or SI or DI) + (8 bit displacement (sign
extended ) or 16 bit displacement
Physical Address = E.A +(DS)*1610

25. Define Immediate Addressing.
An 8 bit or 16 bit immediate data follows the instruction. For e.g MOV
AX,5020H instruction transfers a word 5020H to the AX register .

26. Define Direct Addressing mode :
A 16 bit offset address of the data memory location is specified with
reference to the DS segment starting address.
For.E.g MOV [1020H],5020H instruction transfers a word 5020H to the data memory
location at 11020H if DS=1000H.

27. Define Relative based indexed addressing mode:
Relative Based Indexed Addressing Mode : Effective Address is calculated by the
sum of 8- or 16 bit displacement and a based indexed address.
E.A.= (BX or BP) + (SI or DI) +( 8 bit displacement (sign extended ) or 16 bit
displacement)
Physical Address= E.A + (DS)*1610

28. List the branch related addressing mode:
• Intra segment Direct
• Intra segment Indirect
• Inter segment Direct
• Inter Segment Indirect

29. List the functions of Bus Interface Unit in 8086.
• Sends out addresses
• Fetches instructions from memory
• Reads data from ports and memory
• Writes data to port and memory

30. Write any two advantages of segment registers in 8086
a. It allows the memory capacity to be 1MB even though the address
associated with individual instructions are 16 bits wide.
b. It allows the instruction,data, or stack portion of a program to be more
than 64KB long by using more than one code, data, or stack segment

31. What is the use of Instruction pointer in 8086 ?
Instruction pointer holds the 16 bit address of the next code byte within the
code segment. The value contained in the IP is called effective address or offset.
It contains the distance from the base address to the next instruction byte to be
fetched.

32. Write about the auxiliary carry flag used in 8086 ?
It is set if there is a carry out of bit 3 during an addition or a borrow by bit
3 during a subtraction. This flag is used exclusively for BCD arithmetic.

33. When the Overflow flag is set ?
For addition of 16 bits, this flag is set when there is a carry into the MSB
and no carry out of the MSB.

34. Define Register addressing mode:
Datum is in the register that is specified by the instruction
E.g : MOV CX,AX (16 bit operand)
MOV CL,AL ( 8 bit operand)

35. Define Register Indirect Addressing mode:
Effective address of the datum is in the base register BX or an index
register that is specified by the instruction.

36. Define Register relative addressing mode:
The effective address is the sum of an 8- or 16 bit displacement and the
contents of a base register or an index register.

37. Define Based Indexed addressing mode:
The effective address is the sum of a base register and an index register ,
both of which are specified by the instruction. It is also called as Base related
Indexed addressing.

38. Define Intra segment direct addressing mode:
The effective branch address is the sum of an 8- or 16 bit displacement
and the current contents of IP.

39. Define Intra segment Indirect addressing mode:
The effective branch address is the contents of a register or memory
location that is accessed using any of the data related addressing modes except
the immediate mode. The contents of IP are replaced by the effective branch
address.

40. Define Inter segment addressing mode:
It replaces the contents of IP with part of the instruction and the contents
of CS with another part of the instruction.