STM32L4 User Reference Manual Guide

●The STM32L431xx 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 STM32L431xx devices embed high-speed memories (Flash memory up to 256 Kbyte, 64 Kbyte of SRAM), 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 STM32L431xx devices embed several protection mechanisms for embedded Flash memory and SRAM: readout protection, write protection, proprietary code readout protection and Firewall.

●The devices offer a fast 12-bit ADC (5 Msps), two comparators, one operational amplifier, two DAC channels, an internal voltage reference buffer, a low-power RTC, one general-purpose 32-bit timer, one 16-bit PWM timer dedicated to motor control, four general-purpose 16-bit timers, and two 16-bit low-power timers.

●In addition, up to 21 capacitive sensing channels are available.

●They also feature standard and advanced communication interfaces.

●The STM32L431xx operates in the -40 to +85 °C (+105 °C junction), -40 to +105 °C (+125 °C junction) and -40 to +125 °C (+130 °C 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, OPAMP and comparators. A VBAT input allows to backup the RTC and backup registers.

●The STM32L431xx family offers nine packages from 32 to 100-pin packages.

●Key Features

● Ultra-low-power with FlexPowerControl

● 1.71 V to 3.6 V power supply

● -40 °C to 85/105/125 °C temperature range

● 200 nA in VBAT mode: supply for RTC and 32x32-bit backup registers

● 8 nA Shutdown mode (5 wakeup pins)

● 28 nA Standby mode (5 wakeup pins)

● 280 nA Standby mode with RTC

● 1.0 μA Stop 2 mode, 1.28 μA with RTC

● 84 μA/MHz run mode

● Batch acquisition mode (BAM)

● 4 μs wakeup from Stop mode

● Brown out reset (BOR)

● 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 and DSP instructions

● Performance benchmark

● 1.25 DMIPS/MHz (Drystone 2.1)

● 273.55 CoreMark® (3.42 CoreMark/MHz @ 80 MHz)

● Energy benchmark

● 176.7 ULPBench® score

● 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)

● Internal 48 MHz with clock recovery

● 2 PLLs for system clock, audio, ADC

● Up to 83 fast I/Os, most 5 V-tolerant

● RTC with HW calendar, alarms and calibration

● Up to 21 capacitive sensing channels: support touchkey, linear and rotary touch sensors

● 11x timers: 1x 16-bit advanced motor-control, 1x 32-bit and 2x 16-bit general purpose, 2x 16-bit basic, 2x low-power 16-bit timers (available in Stop mode), 2x watchdogs, SysTick timer

● Memories

● Up to 256 KB single bank Flash, proprietary code readout protection

● 64 KB of SRAM including 16 KB with hardware parity check

● Quad SPI memory interface

● Rich analog peripherals (independent supply)

● 1× 12-bit ADC 5 Msps, up to 16-bit with hardware oversampling, 200 μA/Msps

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

● 1x operational amplifier with built-in PGA

● 2x ultra-low-power comparators

● 16x communication interfaces

● 1x SAI (serial audio interface)

● 3x I2C FM+(1 Mbit/s), SMBus/PMBus

● 4x USARTs (ISO 7816, LIN, IrDA, modem)

● 1x LPUART (Stop 2 wake-up)

● 3x SPIs (4x SPIs with the Quad SPI)

● CAN (2.0B Active) and SDMMC interface

● SWPMI single wire protocol master I/F

● IRTIM (Infrared interface)

● 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™