Microprocessors Questions and Answers for Viva

Answer-1: A microprocessor is an integrated circuit that acts as the central processing unit (CPU) of a computer. It executes instructions and performs arithmetic and logic operations.

Answer-2: Basic components of a microprocessor are,
1. control unit
2. Input/Output(I/O) unit
3. Arithmatic and Logic Unit(ALU),
4. Registers
5. Cache.

Answer-3: The ALU performs arithmetic and logic operations, such as addition, subtraction, AND, OR, and NOT, on data within the microprocessor.

Answer-4: The Control Unit manages the execution of instructions, fetching them from memory, decoding them, and coordinating the operation of other components within the microprocessor.

Answer-5: The Intel 4004, released in 1971, was the world's first commercially available microprocessor. It marked the beginning of the microprocessor revolution.

Answer-6: Microprocessors communicate with external devices through input/output (I/O) operations, using interfaces such as serial ports, USB, Ethernet, and GPIO (General Purpose Input/Output) pins.

Answer-7: Moore's Law states that the number of transistors on a microchip doubles approximately every two years, leading to exponential increases in computing power and performance for microprocessors.

Answer-8: The clock speed, measured in Hertz (Hz), determines how many instructions a microprocessor can execute per second. Higher clock speeds generally result in faster processing.

Answer-9: Pipelining is a technique used in microprocessor design where multiple instructions are overlapped in execution to improve throughput and performance.

Answer-10: RISC (Reduced Instruction Set Computer) architectures have a smaller set of simple instructions, while CISC (Complex Instruction Set Computer) architectures have a larger set of more complex instructions.

Answer-11: Cache memory is a small, high-speed memory integrated into the microprocessor or located nearby. It stores frequently accessed data and instructions to reduce access time and improve overall performance.

Answer-12: Accumulator is an 8 bit register which stores data and performs arithmetic and logical operations. The result of the operation is stored in the accumulator. It is designated by the letter ‘A’.

Answer-13: There are 5 different flags in 8085 microprocessor. Though the flag register is of 8 bit but 3 bits are not in use. Only 5 bits are used for the different flags. They are:-
Sign flag(s),
Zero flag(z),
Auxiliary carry(AC),
Parity flag (P),
Carry flag

Answer-14: There are 6 general purpose registers in 8085 microprocessor. They are designated by the letters – B, C, D, E, H, and L. These are 8 bit registers and are used to store data temporarily during the execution of any program. These registers can also be used to store 16 bit data by using them in pairs i.e. BC, DE and HL. These pairs cannot be changed as B cannot pair with any other register other than C.

Answer-15: Program counter holds a location in memory of the next step to be performed or the ‘s locationnext step’s location in a set of steps in case of multistep instruction. In all cases, the counter is increased by one as steps are progressed. Also, the program register keeps the address of the next instruction.

Answer-16: The processor made of PMOS / NMOS/ HMOS/ HCMOS technology is called 1st, 2nd, 3rd, 4th generation processor, and it contains 4/8/16/32 bits.

Answer-17: Tri-state logic is the three logic levels used; they are High, Low, High impedance state. High impedance is electrical open circuit conditions in which high and low are normal logic levels.

Answer-18: Stack pointer is of 16 bits length and is used to point to the value at top of the stack for the currently executed instruction.

Answer-19: 8085 has 8 data lines and 16 address lines. The memory size of any microprocessor depends on the number of address lines. The general formula is 2n, where n= number of address lines. For 8085 there are  216= 64 Kbytes memory size.

Answer-20: There are 6 types of interrupts in 8085. They are, TRAP, RST 7.5, RST 6.5, RST 5.5, INTR, Interrupt acknowledgment (INTA(bar))