Embedded C 面试题与答案

问题 26. Explain the role of a timer in embedded systems.

Timers are used to measure time intervals, generate time delays, or trigger events at specific intervals, crucial for tasks like real-time control.

问题 27. What is the purpose of the 'volatile' qualifier in function arguments?

The 'volatile' qualifier in function arguments indicates that the argument may change unexpectedly, even if it appears not to be modified within the function.

Example:

void process_data(volatile int data);

问题 28. Explain the concept of DMA (Direct Memory Access) in embedded systems.

DMA allows peripherals to directly access the system's memory without involving the CPU, improving data transfer speed and reducing CPU overhead.

问题 29. What is the purpose of the 'attribute' keyword in GCC (GNU Compiler Collection)?

The 'attribute' keyword is used to specify additional information to the compiler, such as optimizing for size or alignment.

Example:

attribute((packed)) struct PackedStruct { / members */ };

问题 30. Explain the concept of stack and heap in embedded systems.

The stack is used for local variables and function call management, while the heap is used for dynamic memory allocation, managed by the programmer.