STM32 Dev

Setting up the development environment :

This post explains how to setup a proper development environment for the STM32 microcontroller, specifically the STM32F4-discovery board, without any dependency on eclipse or other IDEs.

First of all, install the required dependencies : (This assumes that you have Debian/Ubuntu Linux)

apt-get install build-essential git flex bison libgmp3-dev
libmpfr-dev libncurses5-dev libmpc-dev autoconf texinfo libtool 
libftdi-dev libusb-1.0-0-dev zlib1g zlib1g-dev python-yaml

You’ll have to setup a toolchain :

git clone https://github.com/jmfriedt/summon-arm-toolchain

This shell script is modified to support gcc-5.3 and libopencm3, a free low level firmware library for Cortex-m development.

./summon-arm-toolchain

Now it should start downloading the required files and installing the compiled binaries, and libraries to ~/sat/
Throw up a terminal and edit .bashrc :

nano ~/.bashrc

Add this export to define the toolchain for the system :

export PATH=/home/YOUR_USER/sat/bin:$PATH

Then source the .bashrc file :

source ~/.bashrc

Once the toolchain have been set up, it’s time to install texane st-link, an open source version of the STMicroelectronics stlink tools : Make sure you installed the required dependencies first :

apt-get install build-essential pkg-config intltool cmake libusb-1.0 
libusb-1.0.0-dev

Clone stlink and compile it.

cd ~/
git clone https://github.com/texane/stlink
cd stlink

./autogen.sh 
./configure --with-gtk-gui
 make

You can now copy the compiled binaries to /bin and give them permissions :

cp st-* /bin/
chmod s+x /bin/st-*

If everything worked smoothly, you can download the libopencm3-examples and try one to flash an example :

cd ~/
git clone https://github.com/libopencm3/libopencm3-examples

Initialize the libopencm3 library (only for the examples, or you can modify the main Makefile in libopencm3-examples to point to ~/sat/arm-none-eabi/include/libopencm3/ )

cd libopencm3-examples
git submodule init
git submodule update

Run make now, and flash one of the examples :

make 
cd examples/stm32/f4/stm32f4-discovery/miniblink
make flash

Makefile :

Suppose you need to program something and you don’t need to place it inside the libopencm3-examples directory, here’s a simple makefile (designed for STM32F4 ) :

cd ~/Project_dir/ 
cp -avr ../libopencm3-examples/examples/stm32/f4/stm32f4-discovery/example .
cd example

Now, you can save this Makefile to the same directory :

NAME=usart_irq

# Toolchain 
CC = arm-none-eabi-gcc
OC = arm-none-eabi-objcopy

# Compiler Flags 
CFLAGS = -Wextra -Wimplicit-function-declaration
CFLAGS += -Wredundant-decls -Wmissing-prototypes
CFLAGS += -Wstrict-prototypes -Wundef -Wshadow -fno-common

# Architecture flags
ARCH_FLAGS = -mcpu=cortex-m4 -mthumb 
ARCH_FLAGS += -mfloat-abi=hard -mfpu=fpv4-sp-d16
SPECFLAGS = -MD -DSTM32F4

# Linker file (Memory maps)
LINKER = stm32f4-discovery.ld

# Required Libs
LIBS = -lopencm3_stm32f4 -lc -lgcc -lnosys

# Libopencm3 includes 
INCLUDES = -I~/sat/arm-none-eabi/include

# Libopencm3 libraries from summon-arm-toolchain 
LIBOPENCM3 = -L~/sat/arm-none-eabi/lib/thumb/cortex-m4 
LIBOPENCM3 += -L~/sat/arm-none-abi/lib

# Linker Flags
LDFLAGS = --static -Wl,--start-group $(LIBS)
LDFLAGS += -Wl,--end-group $(LIBOPENCM3) -T$(LINKER) 
LDFLAGS += -nostartfiles -Wl,--gc-sections  $(ARCH_FLAGS)

# Linker Objects 
OBJS = $(NAME).o

all : $(NAME).bin

$(NAME).bin: $(NAME).elf
    $(OC) -Obinary $(NAME).elf $(NAME).bin

$(NAME).o: $(NAME).c
    $(CC) -Wall $(CFLAGS) $(INCLUDES) $(ARCH_FLAGS) \
$(SPECFLAGS) -c $(NAME).c

$(NAME).elf: $(NAME).o
    $(CC) -o $(NAME).elf $(OBJS) $(LDFLAGS)

flash: $(NAME).bin
    st-flash write $(NAME).bin 0x8000000

clean:
    rm *.elf *.o *.d

Add the required linker file (memory map of the specific STM32 board) :

libopencm3-examples/examples/stm32/f4/stm32f4-discovery/stm32f4-discovery.ld

Compile and flash the example :

make ; make flash

You’re good to go