Embedded Systems & Firmware

What is the role of a microcontroller's brown-out detector (BOD, brown-out reset)?

  1. ATo reset the microcontroller when the supply voltage drops below what operation requires, preventing unreliable behavior
  2. BTo turn on an LED when the room gets dark
  3. CTo raise the supply voltage automatically
Show answer and explanation

Answer: A. To reset the microcontroller when the supply voltage drops below what operation requires, preventing unreliable behavior

When a draining battery or unstable supply lowers the voltage, the microcontroller's circuits are no longer guaranteed to work, and it may execute instructions incorrectly or write garbage to flash. A brown-out detector holds the microcontroller in reset while the voltage is below a set threshold and lets it start only after the voltage has recovered sufficiently. It is an important feature for protecting data.

  • A. Correct. It also prevents corrupt flash writes and similar.
  • B. It is not a light sensor function.
  • C. It does not raise the voltage.
Practice this topic Back to topic

More Embedded Systems & Firmware questions

  1. On a microcontroller with interrupt priorities, a higher-priority interrupt occurs while a lower-priority handler is running. What generally happens (assuming nesting is allowed)?
  2. In C, which statement sets only bit 3 of register reg to 1 without changing the other bits?
  3. In C, which statement clears only bit 3 of register reg to 0 without changing the other bits?
  4. To toggle an LED output pin bit between on and off each time the code runs, which C statement is correct?
  5. Which C condition correctly tests whether bit 5 of input register in is 1?