This is the documentation for the latest (main) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

STM32 Mini F401

Overview

The STM32 Mini F401 is an extremely low cost and bare-bones development board featuring the STM32F401CC, see STM32F401CC website 4. More info about the board with schematics available here 2

STM32 Mini F401

Hardware

The STM32F401CC based board provides the following hardware components:

  • STM32F401CCU6 in UFQFPN48 package

  • ARM® 32-bit Cortex® -M4 CPU with FPU

  • 84 MHz max CPU frequency

  • VDD from 1.7 V to 3.6 V

  • 256 KB Flash

  • 64 KB SRAM

  • GPIO with external interrupt capability

  • 1x12-bit, 2.4 MSPS ADC with 16 channels

  • DMA Controller

  • Up to 11 Timers (six 16-bit, two 32-bit, two watchdog timers and a SysTick timer)

  • USART/UART (3)

  • I2C (3)

  • SPI/I2S (4)

  • SDIO

  • USB 2.0 full-speed device/host/OTG controller with on-chip PHY

  • CRC calculation unit

  • 96-bit unique ID

  • RTC

Supported Features

The Zephyr stm32f401_mini board configuration supports the following hardware features:

Interface

Controller

Driver/Component

NVIC

on-chip

nested vector interrupt controller

SYSTICK

on-chip

system clock

UART

on-chip

serial port

GPIO

on-chip

gpio

PINMUX

on-chip

pinmux

FLASH

on-chip

flash

SPI

on-chip

spi

I2C

on-chip

i2c

ADC

on-chip

ADC Controller

USB OTG FS

on-chip

USB device

The default configuration can be found in the defconfig file:

boards/arm/stm32f401_mini/stm32f401_mini_defconfig

Default Zephyr Peripheral Mapping:

  • UART_1 TX/RX : PA9/PA10

  • I2C1 SCL/SDA : PB8/PB9

  • SPI1 CS/SCK/MISO/MOSI : PA4/PA5/PA6/PA7

  • PWM_4_CH1 : PB6

  • PWM_4_CH2 : PB7

  • ADC_1 : PA1

  • SW0 : PB2 (routed to BOOT1 dip switch)

  • LED0 : PC13

Clock Sources

The board has two external oscillators. The frequency of the slow clock (LSE) is 32.768 kHz. The frequency of the main clock (HSE) is 25 MHz.

The default configuration sources the system clock from the PLL, which is derived from HSE, and is set at 84MHz.

Programming and Debugging

There are 2 main entry points for flashing STM32F4X SoCs, one using the ROM bootloader, and another by using the SWD debug port (which requires additional hardware). Flashing using the ROM bootloader requires a special activation pattern, which can be triggered by using the BOOT0 pin, which on this board is a dip switch.

Flashing

Installing dfu-util

It is recommended to use at least v0.8 of dfu-util 3. The package available in debian/ubuntu can be quite old, so you might have to build dfu-util from source.

There is also a Windows version which works, but you may have to install the right USB drivers with a tool like Zadig 1.

Flashing an Application

Connect a USB-C cable and the board should power ON. Force the board into DFU mode by setting the BOOT0 dip switch position to ON. Reset the board with the NRST button.

The dfu-util runner is supported on this board and so a sample can be built and tested easily.

# From the root of the zephyr repository
west build -b stm32f401_mini samples/basic/blinky
west flash

Debugging

The board can be debugged by installing the included 100 mil (0.1 inch) header, and attaching an SWD debugger to the 3V3 (3.3V), GND, SCK, and DIO pins on that header.

References

1

https://zadig.akeo.ie/

2

https://stm32-base.org/boards/STM32F401CCU6-STM32-Mini-F401

3

http://dfu-util.sourceforge.net/build.html

4

https://www.st.com/en/microcontrollers-microprocessors/stm32f401cc.html