WorksheetsEmbedded Systems Quiz - Advanced to Expert
Total questions: 40
Worksheet time: 20mins
You need to reduce electromagnetic interference (EMI) in a high-speed embedded system. Which solution is most effective?
Use long wires
Enable pull-up resistors
Add ground planes and proper trace impedance matching
Reduce voltage only
In an RTOS system, tasks are missing deadlines under high load. What is a robust corrective measure?
Increase task priority randomly
Use fixed priority without deadlines
Perform rate-monotonic or EDF scheduling analysis
Disable interrupts
A system must process sensor data, apply a Kalman filter, and control a motor in real-time. What architecture is ideal?
Single-threaded with polling
Interrupt-based state machine
RTOS with dedicated threads for sensor, filter, and actuator
Bare-metal infinite loop
During testing, your embedded Linux system locks up when writing to NAND flash. Cause?
Flash is full
Wear leveling failure or improper MTD driver usage
Incorrect GPIO
Floating point exception
A real-time system is sensitive to jitter. Which strategy minimizes it?
Use cooperative scheduling
Allocate dynamic memory inside ISR
Use preemptive RTOS with priority inheritance and pin ISR
Use high baud rate UART
You’re using SPI on two slave devices. One receives corrupt data. Root cause?
Clock skew and lack of tri-state MISO management
Interrupt priority mismatch
Shorted pull-up
I2C instead
Your embedded vision system needs fast AI inference. Which is ideal?
Use CPU with delay
Use MCU with floating point
Integrate NPU/TPU accelerator (e.g., Coral, EdgeTPU)
Use EEPROM
A motor controller using a PID algorithm oscillates heavily. What’s the remedy?
Reduce sampling rate
Fine-tune gains and add derivative filtering
Switch to PWM
Remove proportional gain
Your CAN-based embedded system exhibits bus-off errors. What should you do?
Reduce supply voltage
Increase baud rate
Monitor bus load, check termination and software retries
Switch to UART
A real-time embedded system with FreeRTOS runs out of heap. What’s a good strategy?
Switch to polling
Increase configTOTAL_HEAP_SIZE and use heap_4.c
Reduce baud rate
Print heap values
You need to encrypt data on a microcontroller with limited resources. Optimal approach?
Use RSA-4096
Use hardware AES engine or lightweight ciphers like ChaCha20
XOR with 0xFF
Use UDP
You're building a wearable heart monitor. How do you ensure signal stability?
Increase ADC bit count
Apply analog and digital filtering (e.g., Butterworth + IIR)
Increase sample delay
Add PWM fan
In your code, stack overflow corrupts unrelated variables. What’s the advanced protection?
Use heap instead
Stack canary or memory protection unit (MPU)
UART logging
Disable interrupts
System reboots when multiple peripherals are enabled. Cause?
Clock domain crossing issue or power rail overdraw
EEPROM write
ADC overflow
Timer reset
A BLE-based embedded device suffers latency during pairing. Optimal solution?
Lower BLE power
Use just-works pairing
Optimize connection interval and PHY configuration
Use UART instead
You're getting inconsistent ADC readings under motor load. Fix?
Isolate analog and digital ground + use low-pass filter
Reduce PWM frequency
Increase baud rate
Remove bypass cap
Your bootloader must verify firmware authenticity. What’s the most secure method?
CRC
Hash with SHA256 + digital signature verification (e.g., ECDSA)
UART parity
EEPROM checksum
You're debugging a race condition in a multicore system. What’s the recommended method?
Add delays
Use hardware semaphores, mutexes with memory barriers
Increase loop count
Disable interrupts
Embedded Linux fails to boot due to rootfs error. What's your approach?
Format EEPROM
Use initramfs + failover to alternate partition (A/B)
Increase timeout
Disable bootloader
An automotive embedded ECU must log sensor events with cryptographic assurance. Best approach?
Use UART log
Hash logs and sign with HSM or secure element
Print on display
Use EEPROM only
You’re designing a safety-critical system for automotive ABS. What is the most appropriate development standard?
ISO 27001
ISO 26262 for functional safety
MISRA-C only
AUTOSAR Classic
A secure bootloader must detect tampered firmware at runtime. What cryptographic primitive is essential?
Base64 encoding
CRC32 checksum
Digital signature with asymmetric key (e.g., ECDSA, RSA)
XOR masking
You need sub-microsecond task switching in a high-performance embedded system. Which architecture is ideal?
Harvard architecture MCU
ARM Cortex-M3
DSP with RTOS & hardware context switching (e.g., TI C2000)
8051
Your RTOS-based system shows deadlock during inter-task communication. How can you detect and prevent this?
Disable interrupts
Use static variables
Apply priority inheritance protocol and avoid circular waits
Increase stack size
For a battery-powered sensor node requiring <1μA sleep current, which MCU features are critical?
16-bit ADC
Deep Sleep (STOP/STANDBY) with RTC and SRAM retention
JTAG access
Floating-point unit
In a real-time video processing embedded platform, jitter is introduced during frame capture. Likely reason?
GPIO noise
Improper buffer synchronization or cache coherency issues
Floating point rounding
Delay in ISR
A multi-core embedded processor requires synchronization without hardware locks. What approach is best?
Memory barriers + atomic instructions (e.g., LDREX/STREX on ARM)
Timer polling
Disabling interrupts on all cores
UART-based control
You’re tasked with securing firmware OTA updates over MQTT. What protocol stack ensures confidentiality and integrity?
MQTT only
MQTT over TCP
MQTT over TLS with client/server certificates
HTTP POST
A DO-178C certified avionics embedded system experiences intermittent failures. What's your highest priority action?
Replace the RTOS
Conduct fault tree analysis (FTA) and inject software test coverage
Update compiler
Format EEPROM
Your cryptographic functions run slow on a secure IoT node. Which hardware enhancement resolves this?
Double clock
Add HSM or cryptographic accelerator with hardware entropy
Optimize GPIO
Remove ISR
You are debugging real-time tasks and missing deadline constraints. What is a rigorous solution?
Print task name
Use real-time trace analyzers (e.g., SEGGER SystemView or Tracealyzer)
Add infinite loop
Disable watchdog
An embedded AI model trained offline doesn’t perform well on-device. What’s a probable cause?
EEPROM overflow
Quantization error or lack of hardware acceleration
PWM interference
Bootloader timing
To ensure deterministic execution in RTOS, what must be minimized?
Task priority
Interrupt nesting
Jitter and context switch latency
SPI frequency
A power-fail-safe write operation to external Flash is needed. What’s a safe design approach?
Use EEPROM
Use write-ahead logging with capacitor-backed RAM buffer
Toggle GPIO after write
Increase SPI clock
Your embedded ML application shows inconsistent behavior due to memory fragmentation. What do you do?
Switch to Python
Use static memory pools and custom allocators
Use malloc() frequently
Increase heap
A secure embedded device must be tamper-evident. What hardware solution is recommended?
Watchdog timer
Power-efficient MCU
Tamper pins and secure fuses with self-destruct on violation
SPI flash
You're implementing redundancy in a flight control system. What is a common embedded design principle?
Use FPU
Triple Modular Redundancy (TMR) and voting logic
Overclock processor
Lower ADC rate
An embedded system is vulnerable to fault injection attacks. What is a strong countermeasure?
Use larger resistors
Add debug port
Redundant computation with timing noise detection
Increase flash speed
For industrial automation using real-time Ethernet (e.g., EtherCAT), what timing precision is typically expected?
±1 ms
±100 μs
±1 μs
±100 ns
To ensure forward secrecy in embedded secure communication, what cryptographic method is applied?
Shared symmetric key
ECDH ephemeral key exchange with per-session keys
RSA without padding
SHA-1 hashing
