Top Embedded Systems Interview Questions with Answers
Embedded C is a version of the C programming language tailored for microcontrollers and other small, low-power devices. It includes specific extensions and modifications to the standard C language to meet the requirements of embedded systems, such as limited memory and processing power, real-time constraints, and the need for interfacing with hardware peripherals.
Explain the concept of a void pointer in embedded C programming.
In embedded C programming, a void pointer can pass a pointer to a function without declaring the type of data it is pointing to. This flexibility in function calls is helpful in situations where the data type may be determined dynamically at runtime.
What is a segmentation fault in embedded C programming?
A segmentation fault can occur due to limited memory and processing power compared to desktop computers. For instance, if a program exhausts all available memory on a device, it may result in a segmentation fault when it attempts to allocate more memory.
Describe a stack overflow error in embedded C programming.
A stack overflow error in embedded C programming happens when too much memory is used on the stack, causing overflow into adjacent memory spaces. This can occur due to reasons such as infinite recursion, large data structures placed on the stack, or excessive stack usage.
What is the concept of embedded systems?
Embedded systems are computer systems integrated into larger devices or systems dedicated to performing specific tasks. They are designed to execute a limited number of functions and are meant to be used in a specific manner.
Explain the use of the “volatile” keyword in embedded C programming.
The volatile keyword in embedded C programming tells the compiler that a variable might be modified by an external event, such as an interrupt service routine or hardware.
Describe the use of the “const” keyword in embedded C programming.
The const keyword in embedded C programming is used to declare a constant value that cannot be modified during the execution of a program.
What is the purpose of static variables in embedded C programming?
In embedded C programming, static variables, declared with the static keyword, are local to a function or file. They retain their value between invocations of the function or between different executions of the program.
Define ISR in embedded C programming.
In embedded C programming, ISR stands for Interrupt Service Routine. An ISR is a type of function executed in response to an interrupt. Interrupts are external events like a button press or a timer expiry that temporarily halt the normal flow of program execution and cause the microcontroller to jump to the ISR.
Why is a bootloader necessary in embedded C programming?
A bootloader is a small program that runs on an embedded system before the main program. It is responsible for initializing the hardware and loading the main program into memory.
What is startup code?
Startup code is a piece of code called before the execution of the main function. It establishes a basic platform for the application and is typically written in assembly language.
What does ISR stand for?
ISR stands for Interrupt Service Routine. It is a procedure stored at a specific memory location and is called when certain interrupts occur. Interrupts are signals sent to the processor indicating high-priority events that require immediate attention.
Can you declare a static variable in a header file?
Variables defined as static are initialized once and persist until the end of the program. They are local to the block in which they are defined. While it is possible to define a static variable in a header file, it is not recommended because each source file that includes the header will have a private copy of the variable.
Related: SOC Physical Design Interview Questions
Which type of loop is better: counting up from zero or counting down to zero?
Counting down to zero loops are better than counting up loops in embedded C programming. This is because the compiler can optimize the comparison to zero at the time of loop termination, resulting in more efficient code.
What are the reasons for segmentation faults in Embedded C, and how can you avoid these errors?
Segmentation faults can occur due to:
- Dereferencing NULL pointers
- Writing to read-only memory
- Dereferencing uninitialized pointers
- Dereferencing freed pointers
- Accessing arrays beyond their boundaries
- To avoid these errors, always initialize pointers, check for NULL before dereferencing, and ensure that array accesses are within bounds.
