Foreword

Due to the rapid spread of the COVID-19 epidemic in Europe and America, the delivery dates for many of the microcontroller manufacturers around the world have been extended from four months to eight months, and the prices are also rising. These might not improve until the end of the year; therefore it is relatively important to choose a microcontroller manufacturer whose supply cycle is not affected by the environment. Many companies developed a sense of urgency due to the outbreak of this epidemic, and Nuvoton is an excellent choice when you are having product shortages. 

Introduction

The latest microcontroller NuMicro® M251 series released by Nuvoton adopts the newest 48 MHz Cortex®-M23 kernel with Arm V8-M architecture, 32 KB to 256 KB of built-in Flash memory, 8 KB to 32 KB of SRAM, a wide operating voltage of 1.8V to 5.5V, and it can be used for an industrial specification operating temperature of -40°C to 105°C; the wide voltage range not only makes it suitable for single-cell lithium battery power supply applications, but it is also suitable for the 5V power supply commonly used in industrial control applications. In terms of EFT anti-interference, the M251 from Nuvoton can provide as high as 4.4 kV of anti-interference capability, so it will not reset or crash under noisy environments.

The NuMicro® ML51 series that inherited the low power 8051 kernel provides richer selections for pin-compatible product upgrades. For products such as Industrial Internet of Things (IIoT) sensing equipment and collection terminal related applications that focus on cost and low power, such as smart meters, multi-sensor systems, handheld devices, and instrument systems, the wirings for this terminal equipment are usually difficult when installed in wide areas, and it is unlikely that their batteries will be changed manually all the time. Therefore, low power is the key to let these nodes operate for extended periods.

NuMicro® M251 provides five power management modes which include normal operation, idle mode, sleep mode, sleep quick wakeup mode, and deep sleep mode; under deep sleep mode (RTC operates and RAM data is retained), the power consumption can reach 1.7 µA, and independent Vbat pin is provided; the low leakage current energy-saving technology also includes low power UART and a wakeup time from the power-saving mode of only 10 µs. Several wakeup sources are also provided, including USCI, RTC, WDT, I2C, UART, GPIO, USBD, Tamper, ACMP, Debug, and Reset; designers can use these power-saving modes to prolong the usage life of batteries. 

Features

• The M251 series provides over ten different models that are pin-compatible, making it more convenient for the customers’ future product upgrades
• Provides 1.8V to 5.5V of wide operating voltage, suitable for the operating voltage of many products
• Provides the Vbat pin and is equipped with an independent power supply, making it particularly suitable for three-meter products
• ESD 7 kV & EFT 4.4 kV high anti-interference capability
• Provides PSIO (Programmable Serial I/O) that can be used for lighting control applications, provides the same lighting effects, and saves more than half of the pins
• Provides several pin packages from as few as 20 pins to as many as 128 pins