Piest Systems Internship Trainee Interview Questions, Process, and Tips

Microcontrollers like STM32, MPC5xxx, and TriCore have different architectures based on their manufacturers and specifications.

• STM32 microcontrollers are based on ARM Cortex-M cores and are widely used in various applications.

• MPC5xxx microcontrollers are from NXP and are commonly used in automotive applications.

• TriCore microcontrollers are from Infineon and are known for their real-time processing capabilities.

GPIO pins in a microcontroller are used for interfacing with external devices by providing input/output functionalities.

• GPIO pins can be configured as either input or output to communicate with external sensors, actuators, or other devices.

• They can be used to read digital signals from sensors or send digital signals to control actuators.

• Examples include using GPIO pins to read a button press, control an LED, or communi...read more

ARM Cortex architecture is significant in embedded systems for its energy efficiency, scalability, and performance.

• ARM Cortex processors are known for their energy efficiency, making them ideal for battery-powered devices.

• The architecture is highly scalable, allowing for a wide range of performance levels to meet different application requirements.

• ARM Cortex processors are widely used in various embedded systems such a...read more

Clock system in a microcontroller can be configured by setting the prescaler, selecting clock source, and enabling interrupts.

• Set the prescaler to divide the clock frequency to the desired value.

• Select the clock source from internal oscillator, external crystal, or external clock input.

• Enable interrupts for clock-related events like overflow or compare match.

• Configure the timer registers to control the timer operation

8-bit, 16-bit, and 32-bit microcontrollers differ in their data bus width, processing power, memory capacity, and cost.

• 8-bit microcontrollers have an 8-bit data bus, lower processing power, and are suitable for simpler applications like household appliances (e.g. ATmega328).

• 16-bit microcontrollers have a 16-bit data bus, better processing power, and are used in applications requiring more complexity like industrial con...read more

Controller Area Network (CAN) protocol is a communication protocol used in the automotive domain for high-speed data exchange between electronic control units (ECUs).

• CAN protocol is a message-based protocol that allows multiple ECUs to communicate with each other without a host computer.

• It is widely used in modern vehicles for various functions such as engine control, transmission control, airbag systems, and more.

• CAN ...read more

LIN protocol is slower, simpler, and cheaper than CAN protocol.

• LIN protocol is typically used for communication between simple electronic control units (ECUs) in automotive applications.

• CAN protocol is faster, more complex, and more expensive, making it suitable for high-speed communication in complex systems.

• LIN protocol has a lower data rate (typically up to 20 kbps) compared to CAN protocol (up to 1 Mbps).

• LIN protoc...read more

UART, I2C, and SPI are serial communication protocols used in electronics.

• UART (Universal Asynchronous Receiver/Transmitter) is a simple, full-duplex communication protocol commonly used for connecting microcontrollers to peripherals.

• I2C (Inter-Integrated Circuit) is a multi-master, multi-slave communication protocol that uses two wires for communication, making it suitable for connecting multiple devices on the same b...read more

Troubleshooting communication issues over the CAN protocol involves checking physical connections, analyzing network traffic, and verifying software configurations.

• Check physical connections for loose or damaged wires

• Use a CAN bus analyzer tool to monitor network traffic and identify errors

• Verify software configurations such as baud rate, message format, and error handling settings

• Check for any conflicting messages or ...read more

The volatile keyword in embedded C is used to indicate that a variable may change unexpectedly, so the compiler should not optimize its access.

• Prevents compiler optimization of variable access

• Useful for variables that can be changed by external sources (e.g. hardware interrupts)

• Ensures that the variable is always read from memory and not from a register

• Example: volatile int *ptr = (int *)0x1234; // pointer to a memory-

Macro functions are preprocessed by the compiler before compilation, while inline functions are expanded at the point of call.

• Macro functions are expanded by the preprocessor before compilation, while inline functions are expanded at the point of call by the compiler.

• Macro functions can be error-prone due to lack of type checking, while inline functions provide type safety.

• Inline functions can improve code readability ...read more

Bit manipulation in Embedded C programming involves using bitwise operators to manipulate individual bits in variables.

• Use bitwise AND (&), OR (|), XOR (^), left shift (<<), and right shift (>>) operators to manipulate bits.

• Example: Setting a specific bit in a variable - var |= (1 << bit_position);

• Example: Clearing a specific bit in a variable - var &= ~(1 << bit_position);

• Example: Toggl...read more

RTOS is a specialized operating system designed for real-time applications, ensuring timely and predictable responses to events.

• RTOS is used in automotive embedded systems to control critical functions like engine management, braking systems, and airbag deployment.

• It provides deterministic behavior, allowing tasks to be executed within specific time constraints.

• RTOS helps in managing multiple tasks concurrently, priori...read more

Task scheduling in RTOS involves managing and prioritizing tasks to ensure timely execution.

• Task scheduling in RTOS involves assigning priorities to tasks based on their urgency and importance.

• The task scheduler in RTOS decides which task to run next based on the priority assigned to each task.

• An example of a simple task scheduler in RTOS is a round-robin scheduler, where tasks are executed in a circular fashion.

• Anothe...read more

Priority inversion in RTOS can be managed using priority inheritance protocol, priority ceiling protocol, and priority boosting.

• Implement priority inheritance protocol to temporarily raise the priority of the lower priority task to that of the higher priority task it is waiting for.

• Use priority ceiling protocol to assign a priority ceiling to each shared resource, ensuring that a task cannot be preempted by a lower pri...read more

AUTOSAR is a standardized automotive software architecture that aims to enhance scalability, reusability, and maintainability of software in vehicles.

• AUTOSAR stands for Automotive Open System Architecture.

• It provides a common platform for developing software components that can be reused across different automotive systems and manufacturers.

• By standardizing software architecture, AUTOSAR helps reduce development time a...read more

ECU is a crucial component in vehicles that controls various functions such as engine performance, fuel efficiency, emissions, and more.

• ECU is a computerized control unit that manages the engine's operation based on input from various sensors.

• It regulates fuel injection, ignition timing, idle speed, and other critical functions to optimize performance and efficiency.

• ECU also monitors emissions and adjusts settings to e...read more

Bootloaders in automotive systems are implemented and validated through a series of steps including development, testing, and integration.

• Develop bootloader software according to automotive industry standards and requirements.

• Test bootloader functionality on target hardware to ensure proper operation.

• Integrate bootloader into the overall automotive system and verify compatibility with other components.

• Validate bootload...read more