Knorr-Bremse Embedded Software Engineer Interview Questions, Process, and Tips

Storage classes in C define the scope and lifetime of variables.

• Auto: Default storage class for local variables

• Register: Requests a variable to be stored in a register for faster access

• Static: Preserves the value of a variable between function calls

• Extern: Allows access to a variable declared in another file

• Thread Local Storage (TLS): Provides each thread with its own copy of a variable

Preprocessor directives are commands used by the preprocessor to perform tasks before the actual compilation process begins.

• Preprocessor directives start with a # symbol.

• They are used to include header files, define constants, and perform conditional compilation.

• Examples include #include, #define, #ifdef, #ifndef, #endif, #pragma, etc.

Macro code to set a bit in embedded software

• Define a macro using bitwise OR operator to set a specific bit in a register

• Example: #define SET_BIT(reg, bit) ((reg) |= (1 << (bit)))

• Call the macro with the register and bit number as arguments

8 bit microprocessor is called so because it processes data in 8 bit chunks.

• 8 bit microprocessor processes data in 8 bit chunks at a time

• It can handle data in 8 bit binary format

• Examples include Intel 8080, Zilog Z80, and MOS Technology 6502