Efficient Performance Without Sacrificing Power Consumption – Diverse Low Power Modes of the Cortex-M4 Series Products

In recent years, markets such as industrial Internet, big data, cloud applications, IoT wireless modules, and mobile devices have been thriving. The specifications for microcontrollers not only demand performance but also expect to provide diverse low power modes to adapt to system operations in different scenarios.

The new NuMicro M480 series is a high-performance MCU product designed based on the Cortex-M4 core. In addition to a main frequency of up to 192MHz and various peripheral interfaces such as Ethernet, USB high-speed, USB full-speed, and CAN2.0B, the M480 series also supports multiple low power operational mode options, providing users with great design flexibility.

Overall, the M480 series offers the following low power modes:

• Fast Wakeup Power-down

• Normal Power Down

• Low-leakage Power Down

• Standby Power Down

• Deep Power Down

Users can choose the appropriate low power mode for their system based on the following parameters: power consumption requirements, CPU state, clock source, SRAM retention size, wake-up sources, wake-up time, and available peripheral resources.

Below, we highlight the most frequently asked low power modes for the M480 series:

Low-leakage Power Down (LLPD)

Usage Scenario: A common scenario for using the LLPD mode is when the host computer must connect to the module where the MCU is located through the USB interface, such as thermal printer modules or fingerprint recognition modules. It usually enters a power-saving standby state and is awakened by the host computer via USB when needed. The power consumption of LLPD can be as low as 230uA, and it can be awakened through various methods such as wake-up pin, wake-up timer, RTC, BOD, LVR, POR, ACMP, GPIO, Timer, WDT, UART, I2C, USB, USCI, etc. Moreover, the system does not need to reset upon waking up.

Standby Power Down (SPD)

Usage Scenario: When users need lower power consumption than the LLPD mode while requiring to retain partial SRAM data for quick access upon waking, the SPD mode is suitable. The power consumption in SPD mode can be as low as 10.2 uA (supporting 32KB SRAM retention), and the size of SRAM retention can be adjusted. It can be awakened through wake-up pin, wake-up timer, RTC, BOD, LVR, POR, and ACMP.

Deep Power Down (DPD)

Usage Scenario: The lowest power mode provided by the M480 series, with all peripheral functions turned off, can achieve power consumption as low as 0.35uA. In this operational mode, users can choose whether to enable the RTC clock function (0.5uA). This mode is commonly used in IoT node applications, such as smart digital identification water meters. It can be awakened through wake-up pin, wake-up timer, and RTC.