STM32 Sandbox

This is a sandbox full of stuff/garbage for the STM32, specifically the STM32F4 series.

This repository is currently using:

• CMSIS v3.01
• STM32F4xx_StdPeriph_driver v1.0.1

Things to keep in mind if adapting to STM32F1, F2, or F3:

• You'll need to locate the proper device-specific files (stored in libraries/ST folder).
• Much of libcpp has been tested with F1 series. Notably, the gpio.h will not work with F2 or F3 processors right now.

Setup of development environment (22.04)

I'm using the 2020-q4-major revision from the official GCC ARM launchpad repository: https://launchpad.net/gcc-arm-embedded

sudo apt-get install gcc-multilib libncurses5:i386

cd ~/bin
wget https://developer.arm.com/-/media/Files/downloads/gnu-rm/10-2020q4/gcc-arm-none-eabi-10-2020-q4-major-x86_64-linux.tar.bz2
tar xvfj gcc-arm-none-eabi-10-2020-q4-major-x86_64-linux.tar.bz2
rm gcc-arm-none-eabi-10-2020-q4-major-x86_64-linux.tar.bz2
echo 'export PATH=$PATH:~/bin/gcc-arm-none-eabi-10-2020-q4-major/bin:$PATH' >> ~/.bashrc

Installing OpenOCD

sudo apt-get install openocd

Build DSP_Lib (optional)

In the CMSIS directory, you can build the DSP_Lib by running Make. You may need to change the target processor as it is currently M4lf (Cortex M4, little-endians, with floating point).

Connecting to a Target

So far I haven't sorted out why openocd hates me, but the following command works around issues with jimtcl paths:

openocd  -f interface/ftdi/flyswatter2.cfg -f target/stm32f4x.cfg
openocd  -f interface/stlink.cfg -f target/stm32f4x.cfg

Sudo may or may not be neccessary depending on your group configurations. Note: the board/stm32f4discovery.cfg file works well for ST-Link V2 and SWD.

I tend to use gdb to upload code and interact with the JTAG/STM32. The example makefile has a ".gdbinit" target which exports a .gdbinit file that allows you to run arm-none-eabi-gdb from within the project directory, and exposes a "flash" command to upload firmware, and a "reset" command that works around some quirks in either OpenOCD/Flyswatter/Lack-Of-Moon-Alignment:

cd <project>
arm-none-eabi-gdb
> flash

Common Problems

Undefined reference to '__aeabi_f2d', '__aeabi_d2iz', etc

The FPU is only single precision, using doubles cause lots of problems -- if you see an error like this, make sure you are appending 'f' to floats:

// 0.0 doesn't work, 0.0f does.
float val = 0.0f;