8-bit AVR® MCU Low Power Overview

Last modified by Microchip on 2023/11/09 09:02

The 8-bit AVR® microcontroller provides various sleep modes and software-controlled clock gating to tailor the power consumption to the application's requirements. Sleep modes enable the microcontroller to shut down unused modules to save power. When the device enters sleep mode, program execution is stopped and interrupts or reset is used to wake the device again. The individual clock to unused peripherals can be stopped during normal operation or in sleep, enabling a much more fine-tuned power management than sleep modes alone.

If you want to achieve the lowest possible power figures, there are a few things to keep in mind. It is not only the sleep mode that defines the power consumption but also the state of the I/O pins, the quantity of enabled peripheral modules, and so on.

Power consumption is proportional to operating voltage. To conserve power you should consider using the lowest system voltage possible. Additionally, consumption is also directly proportional to clock frequency, and if sleep modes are not utilized, the device should be running as low a frequency as possible.

Tips and Tricks for Lowering Power on an AVR® MCU

  • Use the Power Reduction Register (PRR0) to stop the clock to unused individual peripherals reducing power consumption.

Power Reduction Register

Power Reduction Register Description

  • Use the Digital Input Disable Register (DIDR) to shut off unused digital input buffers and stop leakage current.

Digital Input Disable Circuit

DIDR0 register

DIDR1 register

Visit the "Power Saving Example Project" page to see a code sample to lower AVR MCU power consumption.