Operational Embedded Software Engineer Interview Questions & Answers:

1. Explain me can we use printf inside ISR?

Printf function in ISR is not supported because printf function is not reentrant, thread safe and uses dynamic memory allocation which takes a lot of time and can affect the speed of an ISR up to a great extent.

2. Tell me why embedded system is useful?

With embedded system, it is possible to replace dozens or even more of hardware logic gates, input buffers, timing circuits, output drivers, etc. with a relatively cheap microprocessor.

3. Explain what is return type of ISR?

ISR does not return anything. An ISR returns nothing because there is no caller in the code to read the returned values.

4. Tell me what is interrupt latency?

Interrupt latency is the time required for an ISR responds to an interrupt.

5. Tell me what does DMA address will deal with?

DMA address deals with physical addresses. It is a device which directly drives the data and address bus during data transfer. So, it is purely physical address.

6. Tell me what are the qualifiers in C?

Volatile- it is about instructing the compiler that a variable will change

Constant- it is about instructing the compiler that a variable will not change.

7. Tell me what are real-time embedded systems?

Real-time embedded systems are computer systems that monitor, respond or control an external environment. This environment is connected to the computer system through actuators, sensors, and other input-output interfaces.

8. Tell me can we use any function inside ISR?

We can use function inside ISR as long as that function is not invoked from other portion of the code.

9. Tell me how many types of IPC mechanism you know?

Different types of IPC mechanism are -

☛ Pipes
☛ Named pipes or FIFO
☛ Semaphores
☛ Shared memory
☛ Message queue
☛ Socket

10. Tell me can you have constant volatile variables?

Yes, we can have constant volatile variables