.. zephyr:board:: disco_l475_iot1

Overview

The B-L475E-IOT01A Discovery kit for IoT node allows users to develop applications with direct connection to cloud servers. The Discovery kit enables a wide diversity of applications by exploiting low-power communication, multiway sensing and ARM® Cortex®-M4 core-based STM32L4 Series features.

This kit provides:

64-Mbit Quad-SPI (Macronix) Flash memory
Bluetooth® V4.1 module (SPBTLE-RF)
Sub-GHz (868 or 915 MHz) low-power-programmable RF module (SPSGRF-868 or SPSGRF-915)
Wi-Fi® module Inventek ISM43362-M3G-L44 (802.11 b/g/n compliant)
Dynamic NFC tag based on M24SR with its printed NFC antenna
2 digital omni-directional microphones (MP34DT01)
Capacitive digital sensor for relative humidity and temperature (HTS221)
High-performance 3-axis magnetometer (LIS3MDL)
3D accelerometer and 3D gyroscope (LSM6DSL)
260-1260 hPa absolute digital output barometer (LPS22HB)
Time-of-Flight and gesture-detection sensor (VL53L0X)
2 push-buttons (user and reset)
USB OTG FS with Micro-AB connector
Expansion connectors:
- Arduino™ Uno V3
- PMOD
Flexible power-supply options:
- ST LINK USB VBUS or external sources
On-board ST-LINK/V2-1 debugger/programmer with USB re-enumeration capability:
- Mass storage, virtual COM port and debug port

More information about the board can be found at the Disco L475 IoT1 website_.

Hardware

The STM32L475VG SoC provides the following hardware IPs:

Ultra-low-power with FlexPowerControl (down to 120 nA Standby mode and 100 uA/MHz run mode)
Core: ARM® 32-bit Cortex®-M4 CPU with FPU, frequency up to 80 MHz, 100DMIPS/1.25DMIPS/MHz (Dhrystone 2.1)
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
Up to 24 capacitive sensing channels: support touchkey, linear and rotary touch sensors
16x timers:
- 2x 16-bit advanced motor-control
- 2x 32-bit and 5x 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)
- 2x 12-bit ADC 5 MSPS, up to 16-bit with hardware oversampling, 200 uA/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™

More information about STM32L475VG can be found here:

STM32L475VG on www.st.com_
STM32L475 reference manual_

Supported Features

.. zephyr:board-supported-hw::

Connections and IOs

Disco L475 IoT Board has 8 GPIO controllers. These controllers are responsible for pin muxing, input/output, pull-up, etc.

Note that LED LD1 and SPI1 SCK use the same GPIO pin and cannot be used simultaneously.

Available pins:

For detailed information about available pins please refer to STM32 Disco L475 IoT1 board User Manual_.

Default Zephyr Peripheral Mapping:

UART_1 TX/RX : PB6/PB7 (ST-Link Virtual Port Com)
UART_4 TX/RX : PA0/PA1 (Arduino Serial)
I2C1 SCL/SDA : PB8/PB9 (Arduino I2C)
I2C2 SCL/SDA : PB10/PB11 (Sensor I2C bus)
I2C3 SCL/SDA : PC0/PC1
SPI1 NSS/SCK/MISO/MOSI : PA2/PA5/PA6/PA7 (Arduino SPI)
SPI3 SCK/MISO/MOSI : PC10/PC11/PC12 (BT SPI bus)
PWM_2_CH1 : PA15
PWM_15_CH1 : PB14 (LD2)
USER_PB : PC13
LD1 : PA5 (same as SPI1 SCK)
LD2 : PB14
ADC12_IN5 : PA0
ADC123_IN3 : PC2
ADC123_IN4 : PC3
ADC12_IN13 : PC4
ADC12_IN14 : PC5
DAC1_OUT1 : PA4

System Clock

Disco L475 IoT System Clock could be driven by internal or external oscillator, as well as main PLL clock. By default System clock is driven by PLL clock at 80MHz, driven by 16MHz high speed internal oscillator.

Serial Port

Disco L475 IoT board has 6 U(S)ARTs. The Zephyr console output is assigned to UART1. Default settings are 115200 8N1.

Programming and Debugging

.. zephyr:board-supported-runners::

Disco L475 IoT board includes an ST-LINK/V2-1 embedded debug tool interface.

Applications for the disco_l475_iot1 board configuration can be built and flashed in the usual way (see :ref:build_an_application and :ref:application_run for more details).

Flashing

The board is configured to be flashed using west STM32CubeProgrammer_ runner, so its :ref:installation <stm32cubeprog-flash-host-tools> is required.

Alternatively, OpenOCD or JLink can also be used to flash the board using the --runner (or -r) option:

.. code-block:: console

$ west flash --runner openocd $ west flash --runner jlink

Flashing an application to Disco L475 IoT

Here is an example for the :zephyr:code-sample:hello_world application.

Connect the Disco L475 IoT to your host computer using the USB port, then run a serial host program to connect with your Nucleo board. For example:

.. code-block:: console

$ minicom -D /dev/ttyACM0

Then build and flash the application:

.. zephyr-app-commands:: :zephyr-app: samples/hello_world :board: disco_l475_iot1 :goals: build flash

You should see the following message on the console:

.. code-block:: console

$ Hello World! arm

Debugging

You can debug an application in the usual way. Here is an example for the :zephyr:code-sample:hello_world application.

.. zephyr-app-commands:: :zephyr-app: samples/hello_world :board: disco_l475_iot1 :maybe-skip-config: :goals: debug

.. _Disco L475 IoT1 website: https://www.st.com/content/st_com/en/products/evaluation-tools/product-evaluation-tools/mcu-eval-tools/stm32-mcu-eval-tools/stm32-mcu-discovery-kits/b-l475e-iot01a.html

.. _STM32 Disco L475 IoT1 board User Manual: https://www.st.com/resource/en/user_manual/dm00347848.pdf

.. _STM32L475VG on www.st.com: https://www.st.com/en/microcontrollers-microprocessors/stm32l475vg.html

.. _STM32L475 reference manual: https://www.st.com/resource/en/reference_manual/dm00083560.pdf

.. _STM32CubeProgrammer: https://www.st.com/en/development-tools/stm32cubeprog.html