Jacdac for STM32F0xx and STM32G0xx

This repository contains firmware for Jacdac modules based on STM32F0xx and STM32G0xx chips and is part of the Jacdac Device Development Kit.

Bootloader

This repository contains both the firmware for running services (eg., accelerometer service) on a Jacdac module, and a bootloader which allows for updating the firmware using the Jacdac protocol. This update process can be performed by the user from the Jacdac website (while developing firmware you will typically use a debugger to deploy both the bootloader and the firmware).

Development

The top-level repo to build is jacdac-module-template. It imports as submodules this repo (jacdac-stm32x0) and jacdac-c (which contains platform-independent code implementing Jacdac services, as well as various I2C drivers).

When building your own firmware, you will need to create your own repository from jacdac-module-template template. You can do it by following this link https://github.com/microsoft/jacdac-module-template/generate or using the green "Use this template" button in top-right corner at https://github.com/microsoft/jacdac-module-template If you're just playing around, you can simply clone jacdac-module-template.

All the instructions below use your copy of jacdac-module-template as the root folder. You typically will NOT need to fork jacdac-stm32x0 nor jacdac-c.

The build instructions are here, and not in jacdac-module-template, to avoid them getting stale in its various copies.

Setup

You will need a Unix-like environment to build the firmware (see below for instructions on how to get that on Windows, macOS, and Linux) and the following tools:

• arm-none-eabi-gcc (we've been using 9-2019-q4-major and recently switched to 10-2020-q4-major)
• node.js
• GNU Make

macOS

• install arm-gcc: There are verification errors with brew packages for arm-gcc, so we recommend downloading the -mac.pkg version from Arm.

• setup path: Once you install it, you either need to add /Applications/ARM/bin to your PATH, or symlink binaries like this:

cd /usr/local/bin; ln -sf /Applications/ARM/bin/arm-none-eabi-* .

• install Node.js Node.js can be downloaded from the usual place.

GNU Make comes with macOS.

Linux

• please note that gcc-arm-none-eabi that comes with Ubuntu won't work; we recommend you download it from Arm
• some linux distros have old versions of Node; get at least 14.5.2 from NodeSource
• GNU Make is almost always pre-installed

Windows

You will need a Unix-like environment to build the firmware. Luckily, you most likely already have one - it comes with Git for Windows. If you do not have Git for Windows yet, install it. Then you will need to install GNU Make:

• download GNU Make (without guile) from EzWinPorts

• open Administrator command prompt

• run cd "\Program Files\Git\usr"

• run bin\unzip.exe c:\Users\<you>\Downloads\make-4.3-without-guile-w32-bin.zip replacing <you> with your user name

• Head to Start -> Git Bash. When you type make you should now see make: *** No targets specified and no makefile found. Stop..

• install GNU Arm Embedded Toolchain version 10-2020-q4-major or 9-2019-q4-major (do not use other versions for now).

• Get the .exe installer, and agree to adding the tools to your PATH variable. If the installer fails to add to PATH, then do so yourself, adding: C:\Program Files (x86)\GNU Tools Arm Embedded\10 2020-q4-major\bin

• You will also need to install node.js - take the Windows .msi 64 bit installer. Node may ask you to install build tools for native npm packages - you don't need that to build this repo.

If you run Git Bash again (it has to be restarted to see change in PATH), and type arm-none-eabi-gcc --version you should see something about 10-2020-q4-major, and if you type node --version you should get its version number.

If using Black Magic Probe, connect it to your computer. You should see two COM ports that correspond to it in Device Manager (for example COM7 and COM8). First try the lower numbered one, and if it doesn't work try the other one. In Makefile.user set BMP_PORT = //./COM7 - make sure to add //./.

Now, follow the usual build instructions below.

Note: using WSL2 instead of the bash shell etc coming with Git is not recommended since it cannot access USB for deployment and debugging.

Building firmware

Run make; you should get a successful build.

Upon first run of make, a Makefile.user file will be created. You need to adjust the settings in there - there are comments in there that should guide you through the process.

Deploying firmware

To deploy the firmware to a module you will need a debugger interface. We've had best success with Black Magic Probe - it can connect to the MCU even while it's sleeping (provided it wakes up every now and then).

Other debuggers generally require a reset before connection in that case. There is some support for CMSIS-DAP and ST-LINK/V2 through openocd, but we do not recommend using it due to the sleep issue.

You can convert a $3 Bluepill board into Black Magic Probe.

Following commands can be used to deploy firmware:

• make run BL=1 - deploy bootloader
• make run - deploy firmware
• make full-flash - deploy both bootloader and firmware
• make flash-loop - run flashing process in a loop - you can flash multiple devices in a row this way

Aliases:

• make r for make run
• make l for make flash-loop
• make ff for make full-flash

When deploying for the first time on a given board, run make ff. Later run make r.

Other than the building/deployment targets, the following might be of note:

• make st - print RAM/flash stats for the current firmware
• make stf - same, but break it up by function, not only file
• make gdb - run GDB debugger
• make clean - clean (duh!)
• make drop - build all firmware images specified in DROP_TARGETS

Manual deployment using J-Link/ST-LINK etc.

If you do not want to use Black Magic Probe, you can use combined-*.hex and flash with other tools. We have successfully used a Segger J-Link with J-Flash software; make sure the code is flashed to address 0x8000000. We have also used an original ST-LINK/V2 with the ST-LINK utility. When using these tools you will have to ensure that the target MCU is powered, and that pin 1 on the JTAG/SWD interface is connected to the target programming voltage, otherwise the software may report that it cannot detect the target at all.

When run you build, it will print out something like this:

COMBINE built/touch-sensor-1.0/combined-touch.hex
   text	   data	    bss	    dec	    hex	filename
  14468	      0	   1824	  16292	   3fa4	built/touch-sensor-1.0/app-touch.elf
   3296	      0	   2616	   5912	   1718	built/touch-sensor-1.0/bl-touch.elf

There are two ELF files - one for the application and one for bootloader. Before listing sizes, the Makefile gives path of an Intel HEX file combining both which can be flashed with any software, in this case built/touch-sensor-1.0/combined-touch.hex.

Adding new modules

• create a new repo from jacdac-module-template; let's say the new repo is called jacdac-acme-corp-modules
• update jacdac-stm32 and jacdac-c submodules (eg., with make update-submodules)
• copy targets/_example/ to targets/buzzer-v1.0/ (replacing buzzer-v1.0 with the name of the module or series of modules)
• edit targets/buzzer-v1.0/board.h to match your module
• you likely do not need to edit targets/buzzer-v1.0/config.mk, unless using F0 chip
• edit targets/buzzer-v1.0/profile/module.c to include your module name and used services (follow comments in module.c); see jd_services.h for list of services
• rename module.c to match the type of module (eg. buzzer.c)
• if you have several modules with non-conflicting board.h definitions, you can create more files under targets/buzzer-v1.0/profile/; otherwise you'll need to create targets/thermocouple-v1.0 or something similar
• edit Makefile.user to set TRG, eg. TRG = targets/buzzer-v1.0/profile/buzzer.c
• run make; this will generate a new unique identifier and place as an argument of FIRMWARE_IDENTIFIER macro
• make sure to never change the firmware identifier number, as that will break future firmware updates

If you copy targets/jm-*/profiles/something.c from jacdac-msr-modules to start your own module, remember to rename it, and set the FIRMWARE_IDENTIFIER to 0 (the one in targets/_examples already has it set to 0). This way, the build process will generate a new firmware identifier.

Now, edit DROP_TARGETS in Makefile to only include your buzzer-v1.0 folder (and in future thermocouple-v1.0 etc.). Make sure to remove the string acme-corp-button from DROP_TARGETS.

When you run make drop now, you should get a .uf2 file combining firmware for all your modules.

Adding new services and drivers

This topic is covered in jacdac-c. When adding services or drivers, you can put them in addons/ folder of your modules repo, or submit them as PRs in jacdac-c.

Release process

Use make bump to create a new release. This will ask you for a version number (providing a default that just updates the patch number), update CHANGES.md, create a git tag, and push it to the origin.

If the jacdac-acme-corp-modules repo is public on github, the github action will create a new binary file and place it under dist/fw-VERSION.uf2, so there's nothing else to do.

If you want to build by hand, run make drop after make bump and copy built/fw-VERSION.uf2 to dist/fw-VERSION.uf2 in your release repo. You should probably also copy over CHANGES.md, so your users have some idea of what it being updated.

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.opensource.microsoft.com.

When you submit a pull request, a CLA bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., status check, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.