Atturra Interview Questions and Answers

Interrupts are signals that temporarily halt the execution of a program to handle a specific event.

• When an interrupt occurs in 8051, the program counter is saved on the stack and the interrupt service routine (ISR) is executed.

• The ISR handles the interrupt and then returns control to the main program by restoring the program counter from the stack.

• If an interrupt occurs while another interrupt is being serviced, the second interrupt is queued and handled after the first one i...read more

Von Neumann and Harvard are computer architecture classifications. 8051 belongs to Harvard architecture.

• Von Neumann architecture has a single memory space for data and instructions, while Harvard architecture has separate memory spaces for data and instructions.

• 8051 microcontroller uses Harvard architecture as it has separate memory spaces for program instructions and data.

• Harvard architecture allows simultaneous access to both program memory and data memory, which increases ...read more

The location of current line of execution is stored in the stack when there is an interrupt.

• When an interrupt occurs, the processor saves the current state of execution on the stack.

• The location of the current line of execution is stored in the program counter (PC) register.

• The PC register is pushed onto the stack along with other registers.

• After the interrupt is serviced, the processor pops the saved state from the stack and resumes execution from the PC value.

The 8051 micro-controller consists of CPU, RAM, ROM, Timers, Serial Port, Interrupts, and I/O ports.

• The CPU is the main processing unit of the micro-controller.

• The RAM is used for storing data temporarily.

• The ROM contains the program code that is executed by the CPU.

• The Timers are used for generating precise time delays.

• The Serial Port is used for communication with other devices.

• The Interrupts are used for handling external events.

• The I/O ports are used for interfacing with ...read more

Remove spaces from input string and return output string

• Iterate through each character of the input string

• If the character is not a space, add it to the output string

• Return the output string

Draw half adder and full adder without using EXOR gate.

• Half adder can be implemented using AND and OR gates

• Full adder can be implemented using two half adders and an OR gate

• In half adder, sum is obtained by ORing two inputs and carry is obtained by ANDing two inputs

• In full adder, sum is obtained by using two half adders and an OR gate, and carry is obtained by ANDing three inputs

Microprocessors are general-purpose CPUs while microcontrollers are designed for specific tasks.

• Microprocessors are used in computers, smartphones, and other devices that require complex processing.

• Microcontrollers are used in embedded systems, such as home appliances, automotive systems, and medical devices.

• Microprocessors have separate memory and I/O interfaces while microcontrollers have them integrated on a single chip.

• Microprocessors are more expensive than microcontroll...read more

Logic gates are basic building blocks of digital circuits. They perform logical operations on inputs to produce outputs.

• AND gate: output is 1 only if both inputs are 1

• OR gate: output is 1 if either input is 1

• NOT gate: output is the opposite of the input

• NAND gate: output is 0 only if both inputs are 1

• NOR gate: output is 0 if either input is 1

• XOR gate: output is 1 if inputs are different

• XNOR gate: output is 1 if inputs are the same