原标题：ST STM32L476VG 32位超低功耗MCU开发方案

　　ST公司的stm32L476VG是基于高性能ARM® Cortex®-M4 32位RISC内核的超低功耗MCU,工作频率高达80MHz,100DMIPS性能,Cortex-M4内核具有浮点单源(FPU)单精度,支持多有ARM单精度数据处理指令和数据类型,嵌入高速存储器(高达1MB闪存,高达128KB SRAM),并集成了USB OTG FS, LCD,模拟和音频功能,工作电压1.71V-3.6V.本文介绍了STM32L476VG主要特和框图,以及Discovery探索板32L476GDISCOVERY主要特性,板元件布局图,电路图和材料清单.

　　Ultra-low-power ARM® Cortex®-M4 32-bit MCU+FPU, 100DMIPS, up to 1MB Flash, 128 KB SRAM, USB OTG FS, LCD, analog, audio

　　The STM32L476xx devices are the ultra-low-power microcontrollers based on the high-performance ARM® Cortex®-M4 32-bit RISC core operating at a frequency of up to 80 MHz. The Cortex-M4 core features a Floating point unit (FPU) single precision which supports all ARM single-precision data-processing instructions and data types. It also implements a full set of DSP instructions and a memory protection unit (MPU) which enhances application security. The STM32L476xx devices embed high-speed memories (Flash memory up to 1 Mbyte, up to 128 Kbyte of SRAM), a flexible external memory controller (FSMC) for static memories (for devices with packages of 100 pins and more), a Quad SPI flash memories interface (available on all packages) and an extensive range of enhanced I/Os and peripherals connected to two APB buses, two AHB buses and a 32-bit multi-AHB bus matrix.

　　The STM32L476xx devices embed several protection mechanisms for embedded Flash memory and SRAM: readout protection, write protection, proprietary code readout protection and Firewall. The devices offer up to three fast 12-bit ADCs (5 Msps), two comparators, two operational amplifiers, two DAC channels, an internal voltage reference buffer, a low-power RTC, two general-purpose 32-bit timer, two 16-bit PWM timers dedicated to motor control, seven general-purpose 16-bit timers, and two 16-bit low-power timers. The devices support four digital filters for external sigma delta modulators (DFSDM). In addition, up to 24 capacitive sensing channels are available. The devices also embed an integrated LCD driver 8x40 or 4x44, with internal step-up converter. They also feature standard and advanced communication interfaces.

　　• Three I2Cs

　　• Three SPIs

　　• Three USARTs, two UARTs and one Low-Power UART.

　　• Two SAIs (Serial Audio Interfaces)

　　• One SDMMC

　　• One CAN

　　• One USB OTG full-speed

　　• One SWPMI (Single Wire protocol Master Interface)

　　The STM32L476xx operates in the -40 to +85 ℃ (+105 ℃ junction), -40 to +105 ℃ (+125 ℃ junction) and -40 to +125 ℃ (+130 ℃ junction) temperature ranges from a 1.71 to 3.6 V power supply. A comprehensive set of power-saving modes allows the design of low-power applications. Some independent power supplies are supported: analog independent supply input for ADC, DAC, OPAMPs and comparators, 3.3 V dedicated supply input for USB and up to 14 I/Os can be supplied independently down to 1.08V. A VBAT input allows to backup the RTC and backup registers.

　　STM32L476VG主要特性:

　　• Ultra-low-power with FlexPowerControl

　　– 1.71 V to 3.6 V power supply

　　– -40 ℃ to 85/105/125 ℃ temperature range

　　– 300 nA in VBAT mode: supply for RTC and 32x32-bit backup registers

　　– 30 nA Shutdown mode (5 wakeup pins)

　　– 120 nA Standby mode (5 wakeup pins)

　　– 420 nA Standby mode with RTC

　　– 1.1 μA Stop 2 mode, 1.4 μA Stop 2 with RTC

　　– 100 μA/MHz run mode

　　– Batch acquisition mode (BAM)

　　– 4 μs wakeup from Stop mode

　　– Brown out reset (BOR) in all modes except shutdown

　　– Interconnect matrix

　　• Core: ARM® 32-bit Cortex®-M4 CPU with FPU, Adaptive real-time accelerator (ART Accelerator™) allowing 0-wait-state execution from Flash memory,frequency up to 80 MHz, MPU, 100DMIPS/1.25DMIPS/MHz (Dhrystone 2.1), and DSP instructions

　　• Clock Sources

　　– 4 to 48 MHz crystal oscillator

　　– 32 kHz crystal oscillator for RTC (LSE)

　　– Internal 16 MHz factory-trimmed RC (±1%)

　　– Internal low-power 32 kHz RC (±5%)

　　– Internal multispeed 100 kHz to 48 MHz oscillator, auto-trimmed by LSE (better than ±0.25 % accuracy)

　　– 3 PLLs for system clock, USB, audio, ADC

　　• RTC with HW calendar, alarms and calibration

　　• LCD 8 × 40 or 4 × 44 with step-up converter

　　• Up to 24 capacitive sensing channels: support touchkey, linear and rotary touch sensors

　　• 16x timers: 2 x 16-bit advanced motor-control, 2 x 32-bit and 5 x 16-bit general purpose, 2x 16-bit basic, 2x low-power 16-bit timers (available in Stop mode), 2x watchdogs, SysTick timer

　　• Up to 114 fast I/Os, most 5 V-tolerant, up to 14 I/Os with independent supply down to 1.08 V

　　• Memories

　　– Up to 1 MB Flash, 2 banks read-while-write, proprietary code readout protection

　　– Up to 128 KB of SRAM including 32 KB with hardware parity check

　　– External memory interface for static memories supporting SRAM, PSRAM, NOR and NAND memories

　　– Quad SPI memory interface

　　• 4x digital filters for sigma delta modulator

　　• Rich analog peripherals (independent supply)

　　– 3× 12-bit ADC 5 Msps, up to 16-bit with hardware oversampling, 200 μA/Msps

　　– 2x 12-bit DAC, low-power sample and hold

　　– 2x operational amplifiers with built-in PGA

　　– 2x ultra-low-power comparators

　　• 18x communication interfaces

　　– USB OTG 2.0 full-speed, LPM and BCD

　　– 2x SAIs (serial audio interface)

　　– 3x I2C FM+(1 Mbit/s), SMBus/PMBus

　　– 6x USARTs (ISO 7816, LIN, IrDA, modem)

　　– 3x SPIs (4x SPIs with the Quad SPI)

　　– CAN (2.0B Active) and SDMMC interface

　　– SWPMI single wire protocol master I/F

　　• 14-channel DMA controller

　　• True random number generator

　　• CRC calculation unit, 96-bit unique ID

　　• Development support: serial wire debug (SWD), JTAG, Embedded Trace Macrocell™

　　图1.STM32L476xx系列框图

　　STM32L476VG MCUDiscovery kit 32L476GDISCOVERY

　　The 32L476GDISCOVERY helps users to develop and share applications with the STM32L4 ultra-low-power microcontrollers.The Discovery kit combines STM32L476 features with LCD, LEDs, audio DAC, sensors (microphone, 3 axis gyroscope, 6 axis compass), joystick, USB OTG, Quad-SPI Flash memory, expansion and probing connectivity. It includes an embedded Ammeter which measures the MCU consumption in low power modes. An external board can be connected thanks to extension and probing connectors

　　图2.32L476GDISCOVERY板外形图

　　32L476GDISCOVERY板主要特性:

　　• STM32L476VGT6 microcontroller featuring 1 Mbyte of Flash memory and 128 Kbytes of RAM in LQFP100 package

　　• On-board ST-LINK/V2-1 supporting USB reenumeration capability

　　• Three different interfaces supported on USB:

　　– Virtual Com Port

　　– Mass storage

　　– Debug port

　　• ARM® mbed™-enabled (see http: //mbed.org)

　　• LCD 24 segments, 4 commons in DIP 28 package

　　• Seven LEDs:

　　– LD1 (red/green) for ST-LINK/V2-1 USB communication

　　– LD2 (red) for 3.3 V power on

　　– LD3 overcurrent (red)

　　– LD4 (red), LD5 (green) two user LEDs

　　– LD6 (green), LD7 (red) USB OTG FS LEDs

　　• Push-button (reset)

　　• Four-direction joystick with selection

　　• USB OTG FS with Micro-AB connector

　　• SAI Audio DAC, stereo with output jack

　　• Digital microphone MEMS

　　• Accelerometer and magnetometer MEMS

　　• Gyroscope MEMS

　　• 128-Mbit Quad-SPI Flash memory

　　• STM32 current ammeter with 4 ranges and auto calibration

　　• I2C extension connector for external board

　　• Four power supply options:

　　– ST-LINK/V2-1

　　– USB FS connector

　　– External 5V

　　– CR2032 battery (not provided)

　　• Extension connectors

　　• Comprehensive free software including a variety of examples, part of STM32Cube package

　　图3.32L476GDISCOVERY板硬件框图

　　详情请见:

en.DM00172179.pdf

en.DM00108832.pdf