ODrive/docs/developer-guide.md

ODrive Firmware Developer Guide

This guide is intended for developers who wish to modify the firmware of the ODrive. As such it assumes that you know things like how to use Git, what a compiler is, etc. If that sounds scary, turn around now.

The official releases are maintained on the master branch. However since you are a developer, you are encouraged to use the devel branch, as it contains the latest features.

The project is under active development, so make sure to check the Changelog to keep track of updates.

Table of contents

• Prerequisites
• Configuring the build
• Building and flashing the Firmware
• Debugging
• Testing
• Setting up an IDE
• STM32CubeMX
• Troubleshooting
• Documentation
• Releases
• Notes for Contributors

Prerequisites

The recommended tools for ODrive development are:

• make: Used to invoke tup
• Tup: The build system used to invoke the compile commands
• ARM GNU Compiler: For cross-comiling code
• ARM GDB: For debugging the code and stepping through on the device
• OpenOCD: For flashing the ODrive with the STLink/v2 programmer
• Python: For running the Python tools

See below for specific installation instructions for your OS.

Depending on what you're gonna do, you may not need all of the components.

Once you have everything, you can verify the correct installation by running:

$ arm-none-eabi-gcc --version
$ arm-none-eabi-gdb --version
$ openocd --version             # should be 0.10.0 or later
$ tup --version                 # should be 0.7.5 or later
$ python --version              # should be 3.7 or later

Linux (Ubuntu)

sudo add-apt-repository ppa:team-gcc-arm-embedded/ppa
sudo apt-get update
sudo apt-get install gcc-arm-embedded
sudo apt-get install openocd
sudo add-apt-repository ppa:jonathonf/tup && sudo apt-get update && sudo apt-get install tup

Arch Linux

sudo pacman -S arm-none-eabi-gcc arm-none-eabi-binutils
sudo pacman -S arm-none-eabi-gdb
sudo pacman -S tup

• OpenOCD AUR package

Mac

First install Homebrew. Then you can run these commands in Terminal:

brew cask install gcc-arm-embedded
brew cask install osxfuse && brew install tup
brew install openocd

Windows

Note: make sure these programs are not only installed but also added to your PATH.

Some instructions in this document may assume that you're using a bash command prompt, such as the Windows 10 built-in bash or Git bash.

• ARM compiler
• Tup
• Make for Windows
• OpenOCD. Also follow the instructions on the ST-LINK/V2 drivers.

Configuring the build

To customize the compile time parameters, copy or rename the file Firmware/tup.config.default to Firmware/tup.config and edit the parameters in that file:

CONFIG_BOARD_VERSION: The board version you're using. Can be v3.1, v3.2, v3.3, v3.4-24V, v3.4-48V, v3.5-24V, v3.5-48V, etc. Check for a label on the upper side of the ODrive to find out which version you have. Some ODrive versions don't specify the voltage: in that case you can read the value of the main capacitors: 120uF are 48V ODrives, 470uF are 24V ODrives.

CONFIG_USB_PROTOCOL: Defines which protocol the ODrive should use on the USB interface.

• native: The native ODrive protocol. Use this if you want to use the python tools in this repo.
• native-stream: Like the native ODrive protocol, but the ODrive will treat the USB connection exactly as if it was a UART connection. Use this if you're on macOS. This is necessary because macOS doesn't grant our python tools sufficient low-level access to treat the device as the USB device that it is.
• none: Disable USB. The device will still show up when plugged in but it will ignore any commands.

Note: There is a second USB interface that is always a serial port.

CONFIG_UART_PROTOCOL: Defines which protocol the ODrive should use on the UART interface (GPIO1 and GPIO2). Note that UART is only supported on ODrive v3.3 and higher.

• native: The native ODrive protocol. Use this if you're connecting the ODrive to a PC using UART and want to use the python tools to control and setup the ODrive.
• ascii: The ASCII protocol. Use this option if you control the ODrive with an Arduino. The ODrive Arduino library is not yet updated to the native protocol.
• none: Disable UART.

You can also modify the compile-time defaults for all .config parameters. You will find them if you search for AxisConfig, MotorConfig, etc.

Building and flashing the Firmware

1. Run make in the Firmware directory.
2. Connect the ODrive via USB and power it up.
3. Flash the firmware using odrivetool dfu.

Flashing using an STLink/v2 programmer

• Connect GND, SWD, and SWC on connector J2 to the programmer. Note: Always plug in GND first!
• You need to power the board by only ONE of the following: VCC(3.3v), 5V, or the main power connection (the DC bus). The USB port (J1) does not power the board.
• Run make flash in the Firmware directory. Note: If you receive the error can't find target interface/stlink-v2.cfg or similar, create and set an environment variable named OPENOCD_SCRIPTS to the location of the openocd scripts directory.

If the flashing worked, you can connect to the board using the odrivetool.

Testing

The script tools/run_tests.py runs a sequence of automated tests for several firmware features as well as high power burn-in tests. Some tests only need one ODrive and one motor/encoder pair while other tests need a back-to-back test rig such as this one. In any case, to run the tests you need to provide a YAML file that lists the parameters of your test setup. An example can be found at tools/test-rig-parallel.yaml. The programmer serial number can be found by running Firmware/find_programmer.sh (make sure it has the latest formware from STM).

The test script commands the ODrive to high currents and high motor speeds so if your ODrive is connected to anything other than a stirdy test-rig (or free spinning motors), it will probably break your machine.

Example usage: ./run_tests.py --test-rig-yaml ../tools/test-rig-parallel.yaml

Debugging

• Run make gdb. This will reset and halt at program start. Now you can set breakpoints and run the program. If you know how to use gdb, you are good to go.

Setting up an IDE

For working with the ODrive code you don't need an IDE, but the open-source IDE VSCode is recommended. It is also possible to use Eclipse. If you'd like to go that route, please see the respective configuration document:

• Configuring VSCode
• Configuring Eclipse

STM32CubeMX

This project uses the STM32CubeMX tool to generate startup code and to ease the configuration of the peripherals. You can download it from here. All CubeMX related files are in Firmware/Board/v3.

You will likely want the pinout for this process. It is available here.

Generate code

• Run stm32cubeMX and load the Firmware/Board/v3/Odrive.ioc project file.
• Press Project -> Generate code
• You may need to let it download some drivers and such.
• After generating/updating the code, some minor patches need to be applied. To do this, run: git apply Firmware/Board/v3/*.patch
• Run git config --local core.autocrlf input. This will tell git that all files should be checked in with LF endings (CubeMX generates CRLF endings).
• git status will still claim that many files are modified but the actual diff (using git diff) is empty (apart from all the line ending warnings).

Generating patchfiles

If you made changes to CubeMX generated files outside of the USER CODE BEGIN...USER CODE END sections and contribute them back, please add a patch file so that the next person who runs CubeMX doesn't run into problems.

CubeMX will reset everything outside these sections to the original state; we will capturing into a patch file the changes required to undo this resetting.

• Make sure your current desired state is committed.
• Make a new temporary branch: git checkout -b cubemx_temp
• Run the CubeMX code generation as described in the previous section, including applying previous patches.
• The diff will now not be empty since CubeMX reset your changes.
• Stage this state and commit it with a message like "CubeMX reset my changes".
• Run git revert HEAD to undo the resetting action CubeMX's regeneration had. This is the commit which you will export, so write a meaningful commit message.
• Run git format-patch HEAD~1 to export the commit as patch file.
• Check out your previous branch and then force-delete the temporary branch: git branch -D cubemx_temp
• Move the patch file to Firmware/Board/v3/ and add it in a new commit.

Troubleshooting

LIBUSB_ERROR_IO when flashing with the STLink/v2

Problem: when I try to flash the ODrive with the STLink using make flash I get this error:

Open On-Chip Debugger 0.10.0
Licensed under GNU GPL v2
For bug reports, read
	http://openocd.org/doc/doxygen/bugs.html
Info : auto-selecting first available session transport "hla_swd". To override use 'transport select <transport>'.
Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD
adapter speed: 2000 kHz
adapter_nsrst_delay: 100
none separate
Info : Unable to match requested speed 2000 kHz, using 1800 kHz
Info : Unable to match requested speed 2000 kHz, using 1800 kHz
Info : clock speed 1800 kHz
Error: libusb_open() failed with LIBUSB_ERROR_IO
Error: open failed
in procedure 'init' 
in procedure 'ocd_bouncer'

Solution: This happens from time to time.

1. Unplug the STLink and all ODrives from your computer
2. Power off the ODrive you're trying to flash
3. Plug in the STLink into your computer
4. Power on the ODrive
5. Run make flash again

Documentation

All *.md files in the docs/ directory of the master branch are served up by GitHub Pages on this domain.

• Theme: minimal by orderedlist
• HTML layout: docs/_layouts/default.html
• CSS style: docs/assets/css/styles.scss
• Site index: docs/_data/index.yaml

To run the docs server locally:

cd docs
gem install bundler
bundle install --path ruby-bundle
bundle exec jekyll serve --host=0.0.0.0

Releases

We use GitHub Releases to provide firmware releases.

1. Cut off the changelog to reflect the new release
2. Merge the release candidate into master.
3. Push a (lightweight) tag to the master branch. Follow the existing naming convention.
4. Push the python tools to PyPI.
5. Edit the release on GitHub to add a title and description (copy&paste from changelog).

Other code maintenance notes

The cortex M4F processor has hardware single precision float unit. However double precision operations are not accelerated, and hence should be avoided. The following regex is helpful for cleaning out double constants: find: ([-+]?[0-9]+\.[0-9]+(?:[eE][-+]?[0-9]+)?)([^f0-9e]) replace: \1f\2

Notes for Contributors

In general the project uses the Google C++ Style Guide, except that the default indendtation is 4 spaces, and that the 80 character limit is not very strictly enforced, merely encouraged.