Power Management
To cut power on a microcontroller, what should be done with unused peripherals such as timers and UARTs?
- AStop the clock supply to those peripherals through configuration registers
- BKeep those peripherals running at maximum speed
- CSet all their pins to output 1
Show answer and explanation
Answer: A. Stop the clock supply to those peripherals through configuration registers
On many microcontrollers, peripheral clocks may be off or on after reset, so firmware configures clocks only for the peripherals in use. With its clock stopped, a peripheral consumes no dynamic switching power. Also, leaving unused pins floating can cause shoot-through current in input circuits, so defining their states reduces power further.
- A. Correct. Most microcontrollers can gate clocks per peripheral.
- B. Running unused circuits wastes power.
- C. Pin settings must consider what is connected.