IoT Hardware Devices and Processors ISE Practice Questions (Page 8)

Questions 36–40

1. 36application · medium

   An engineer is designing a low-cost IoT sensor node that must store calibration data that is written rarely but must persist across power cycles. The device also needs to store a small amount of frequently updated runtime state. Which memory configuration is most appropriate for these requirements?

   • AEEPROM for calibration data and SRAM for runtime state
   • BSRAM for calibration data and DRAM for runtime state
   • CDRAM for calibration data and Flash for runtime state
   • DFlash for both calibration data and runtime state
   Reveal Solution Discussion Select an answer first
2. 37application · medium

   A developer is writing firmware for a microcontroller that controls a motor and reads an emergency stop button. The motor must stop within 10 milliseconds of the button press. The firmware also handles a low-priority data logging task. Which approach best meets the real-time requirement?

   • ARun the data logging task at a higher priority than the emergency stop
   • BPoll the button in the main loop and handle the motor stop in the same loop
   • CUse an RTOS with a high-priority interrupt service routine for the emergency stop
   • DUse a bare-metal program with a delay function before checking the button
   Reveal Solution Discussion Select an answer first
4. 38application · medium

   An IoT device uses an ARM Cortex-M3 microcontroller with 64 KB of RAM. The firmware must handle a time-critical sensor interrupt that requires a response within 10 microseconds, while also performing background data logging. The team is deciding between a bare-metal loop and a real-time operating system (RTOS). What is the most important advantage of using an RTOS in this scenario?

   • AIt allows the interrupt handler to run as a high-priority task, ensuring it preempts background work.
   • BIt provides deterministic scheduling for the time-critical interrupt handler.
   • CIt reduces the memory footprint compared to a bare-metal loop, leaving more RAM for data logging.
   • DIt provides a preemptive multitasking environment where the time-critical response is handled by an ISR and the logging runs as a low-priority task.
   Reveal Solution Discussion Select an answer first
5. 39application · medium

   An engineer is selecting a processor for a smart thermostat that controls an HVAC system. The device needs to read temperature and humidity sensors over I2C, drive a relay to switch the HVAC on/off, and maintain a local schedule. The firmware is fixed and will not be updated frequently. Which hardware choice best matches these requirements?

   • AA microprocessor with external DRAM and an operating system
   • BA microcontroller with integrated Flash, SRAM, I2C, and GPIO peripherals
   • CA microprocessor with a full Linux distribution to manage the schedule
   • DA microcontroller with only UART and no GPIO
   Reveal Solution Discussion Select an answer first
6. 40application · medium

   A company is designing a battery-powered wearable health monitor that must run for 12 months on a small coin-cell battery. The device samples a heart-rate sensor every 10 seconds, stores a few kilobytes of data locally, and transmits the data via Bluetooth Low Energy once per hour. The team is choosing between an ARM Cortex-M0+ microcontroller and an ARM Cortex-A7 application processor. Which consideration is most important for this decision?

   • AThe Cortex-M0+ supports deep-sleep modes with very low current draw, while the Cortex-A7 typically consumes more power even when idle.
   • BThe Cortex-A7 is needed because it supports a full operating system, which is required for BLE communication.
   • CThe Cortex-A7 has a higher clock speed, which is necessary to handle the heart-rate sensor sampling and BLE protocol stack.
   • DThe Cortex-M0+ lacks sufficient memory to store the hourly BLE transmissions, so the Cortex-A7 is required for the data buffer.
   Reveal Solution Discussion Select an answer first