stm32-blue-pill-rust

Rust for STM32 Blue Pill with Visual Studio Code.

Read the article: https://medium.com/@ly.lee/coding-the-stm32-blue-pill-with-rust-and-visual-studio-code-b21615d8a20

Based on:

1. Jorge Aparicio's Discovery book: https://japaric.github.io/discovery/

2. Jorge Aparicio's HAL for Blue Pill: https://japaric.github.io/stm32f103xx-hal/stm32f103xx_hal/

3. Jorge Aparicio's Cortex-M Quickstart: https://docs.rs/cortex-m-quickstart/0.2.7/cortex_m_quickstart/

4. Nerijus Arlauskas's Embedded Rust blog: http://nercury.github.io/rust/embedded/experiments/2018/04/29/rust-embedded-01-discovery-vl-flipping-bits.html

Connecting the STM32 Blue Pill to ST-Link V2 USB Debugger

Installation and Usage

Install Prerequisites

• For Ubuntu only: Install required packages (arm-none-eabi-gdb is obsolete)

  sudo apt install pkg-config cmake libssl-dev zlib1g-dev gdb-multiarch curl git
  
  sudo ln -s /usr/bin/gdb-multiarch /usr/bin/arm-none-eabi-gdb

Install ARM Cross-Compiler and Linker

• For Windows:

  1. Install ARM Cross-Compiler and Linker from the ARM Developer Website:
     https://developer.arm.com/open-source/gnu-toolchain/gnu-rm/downloads

  2. Scroll down the page till you find
     Windows 32-bit File: gcc-arm-none-eabi-…-win32.exe
     Click Download
     

  3. Select the "Add path to environment variable" option at the last install step

  4. In Windows Explorer, browse to
     C:\Program Files (x86)\GNU Tools Arm Embedded\7 2018-q2-update\bin
     (The 7 2018-q2-update part may be different for your installation)

  5. Copy the file arm-none-eabi-ar.exe to ar.exe
     This ar.exe workaround is temporary until we find a fix for the Windows Rust build

• For Ubuntu:

  sudo apt install binutils-arm-none-eabi gcc-arm-none-eabi

Check ARM Cross-Compiler Installation

1. Open a new Windows or Ubuntu command prompt (not Windows Bash) and enter

   arm-none-eabi-gcc -v

2. You should see something like version 5.4.1 20160919 (release)

3. If you see no errors, close the command prompt.

4. If you see an error, update your PATH environment variable so that it includes the folder for the ARM ".exe" files.

Install OpenOCD For Debugging Blue Pill

• For Windows:

  1. Download OpenOCD (for debugging the Blue Pill) from the unofficial OpenOCD release website:
     https://github.com/gnu-mcu-eclipse/openocd/releases
     Look for gnu-mcu-eclipse-openocd-…-win64.zip

  2. Unzip the OpenOCD download and copy the OpenOCD files into c:\openocd such that opencd.exe is located in the folder c:\openocd\bin

• For Ubuntu:

  sudo apt install openocd

For Windows only: Install ST-Link USB Driver

1. For Windows only: Download the ST-Link USB driver from the ST-Link Driver Website (email registration required):
   http://www.st.com/en/embedded-software/stsw-link009.html

2. Scroll down and click the Get Software button

3. Unzip the ST-Link download. Double-click the dpinst_amd64.exe installer.

For Windows only: Install Build Tools

1. For Windows only: Install Build Tools for Visual Studio 2017 (needed by rustup) from
   https://aka.ms/buildtools

2. Under "Workloads", select Visual C++ Build Tools.
   Warning: The download is 1.1 GB and you need 4.8 GB of free disk space.

Install rustup

1. Install rustup (the Rust toolchain installer) from
   https://rustup.rs/

2. If you see a message about Windows Defender SmartScreen,  click More Info and Run Anyway.

3. Select the default installation option when prompted.
   For Ubuntu only: Log out and log in again to update the PATH

4. Switch to the nightly Rust toolchain (instead of stable or beta). Open a new Windows or Ubuntu command prompt (not Windows Bash) and enter:

   rustup default nightly

5. Install the rust-std component thumbv7m-none-eabi to cross-compile for ARM Cortex-M3 (the processor used in the Blue Pill):

   rustup target add thumbv7m-none-eabi

Download stm32-blue-pill-rust Source Files

• Download the source files from GitHub:
  (You may install git from https://gitforwindows.org)

  git clone https://github.com/lupyuen/stm32-blue-pill-rust.git
  cd stm32-blue-pill-rust

Install Visual Studio Code

1. Install Visual Studio Code from
   https://code.visualstudio.com/download

2. Launch Visual Studio Code and install the following extensions (just click the links below followed by the Install button and Open Visual Studio Code):

   • Better TOML (bungcip)
     https://marketplace.visualstudio.com/items?itemName=bungcip.better-toml

   • C/C++ (Microsoft)
     https://marketplace.visualstudio.com/items?itemName=ms-vscode.cpptools

   • Native Debug (WebFreak)
     https://marketplace.visualstudio.com/items?itemName=webfreak.debug

   • Rust (kalitaalexey)
     https://marketplace.visualstudio.com/items?itemName=kalitaalexey.vscode-rust

   • Rust (rls) (rust-lang)
     https://marketplace.visualstudio.com/items?itemName=rust-lang.rust

3. In Visual Studio Code, click Install when prompted to install the above extensions

4. Restart Visual Studio Code

5. Click File → Open Workspace

6. Browse to the stm32-blue-pill-rust folder and select workspace.code-workspace

7. In the Explorer → Workspace pane at left, browse to the source folder src and select the Rust source file main.rs

8. When prompted, install the Rust Language Service (RLS), which provides Autocomplete and "Go To Definition" features for Rust.

Compiling the Rust program in Visual Studio Code

1. In Visual Studio Code, click Tasks → Run Build Task.

2. Wait a while for the Rust program to be compiled.

3. Check the log in the Terminal window at the bottom of the Visual Studio Code screen.

4. When you see Finished released [optimized + debuginfo] target(s), that means the Rust program has been compiled successfully.

5. We'll proceed to the next step to run the program.

6. But if you see an error, you'll have to fix the error and recompile the program. Just mouse over the filename and line number in the log, and press Ctrl-click to jump to the offending line of code.

Running the Rust program in Visual Studio Code

1. Click Tasks → Run Task

2. Select Connect To STM32 Blue Pill

3. Check the messages from OpenOCD in the Terminal window at the bottom of Visual Studio Code.

4. When you see Listening on port 3333 for gdb connections, our program is ready to be started on the Blue Pill.

5. Click Debug → Start Debugging

6. Note: There is a bug in the debugger for Ubuntu: gdb stops with an error. To be fixed. Meanwhile you can use the command-line debugger in Ubuntu.

Building from the Command Line

1. Build the application:

   cargo clean
   cargo check --release
   cargo build --release

2. You should see something like:

   Finished release [optimized + debuginfo] target(s) in 1.43s
   

3. Sanity check for the built application

   arm-none-eabi-readelf -h target/thumbv7m-none-eabi/release/stm32-blue-pill-rust

4. You should see something like:

   ELF Header:
     Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
     Class:                             ELF32
     Data:                              2's complement, little endian
     Version:                           1 (current)
     OS/ABI:                            UNIX 1. System V
     ABI Version:                       0
     Type:                              EXEC (Executable file)
     Machine:                           ARM
     Version:                           0x1
     Entry point address:               0x8000cfb
     Start of program headers:          52 (bytes into file)
     Start of section headers:          258948 (bytes into file)
     Flags:                             0x5000200, Version5 EABI, soft-float ABI
     Size of this header:               52 (bytes)
     Size of program headers:           32 (bytes)
     Number of program headers:         3
     Size of section headers:           40 (bytes)
     Number of section headers:         21
     Section header string table index: 20
   

Debugging from the Command Line

1. Launch OpenOCD on a terminal. Scripts are located at /usr/share/openocd/scripts

   • For Windows:

     c:\openocd\bin\openocd -f interface/stlink-v2.cfg -f target/stm32f1x.cfg

   • For Ubuntu:

     openocd -f interface/stlink-v2.cfg -f target/stm32f1x.cfg

2. You should see something like:

   GNU MCU Eclipse 64-bits Open On-Chip Debugger 0.10.0+dev-00487-gaf359c18 (2018-05-12-19:30)
   Licensed under GNU GPL v2
   For bug reports, read http://openocd.org/doc/doxygen/bugs.html
   WARNING: interface/stlink-v2.cfg is deprecated, please switch to interface/stlink.cfg
   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: 1000 kHz
   adapter_nsrst_delay: 100
   none separate
   Info : Listening on port 6666 for tcl connections
   Info : Listening on port 4444 for telnet connections
   Info : Unable to match requested speed 1000 kHz, using 950 kHz
   Info : Unable to match requested speed 1000 kHz, using 950 kHz
   Info : clock speed 950 kHz
   Info : STLINK v2 JTAG v17 API v2 SWIM v4 VID 0x0483 PID 0x3748
   Info : using stlink api v2
   Info : Target voltage: 3.225397
   Info : stm32f1x.cpu: hardware has 6 breakpoints, 4 watchpoints
   Info : Listening on port 3333 for gdb connections
   

3. Start a debug session in another command window:

   arm-none-eabi-gdb -x loader.gdb target/thumbv7m-none-eabi/release/stm32-blue-pill-rust

4. Common GDB commands:

   • step: Execute the current source line, step into functions if present. Same as the step into command in Visual Studio Code.

   • next: Execute the current source line, don't step into functions. Same as the step over command in Visual Studio Code.

   • where: Show stack trace.

   • where full: Show stack trace with local variables.

   More commands: https://darkdust.net/files/GDB%20Cheat%20Sheet.pdf

Visual Studio Code Configuration

Customisation of the Visual Studio Code UI was done through the following files:

Task configuration - .vscode/tasks.json

Defines the following tasks:

1. Connect: Launches OpenOCD. Uses different commands for Ubuntu and Windows (opencd vs c:\opencd\bin\opencd).

2. Build: Executes cargo build --release. Configured as the default build task.

3. Remove: Executes cargo clean

4. Check: Executes cargo check --release

Debugger configuration - .vscode/launch.json

• Launches the following command when the debugger is started:

  arm-none-eabi-gdb -x loader.gdb target/thumbv7m-none-eabi/release/stm32-blue-pill-rust

• This command causes gdb to execute the loader.gdb script at the start of debugging.

• The mandatory parameter target/thumbv7m-none-eabi/release/stm32-blue-pill-rust is redundant. The target is specified again in loader.gdb.

Debugger script - loader.gdb

1. This is the GDB script for loading and running programs in STM32 Blue Pill.

2. Called when debugging begins. Defined in .vscode/launch.json

3. This file used to be .gdbinit, which could not be autoloaded due to autoloading security in GDB.

4. Set architecture to ARM 32-bit. Needed for gdb-multiarch on Ubuntu.

5. Send GDB commands to OpenOCD, which listens on port 3333. Extend the timeout.

6. Disable all messages.

7. Enable ARM semihosting to show debug console output in OpenOCD console.

8. Reset the device.

9. Specify target/thumbv7m-none-eabi/release/stm32-blue-pill-rust as the target program to be debugged. Must be specified here (not the command line) because the VSCode debugger will fail without it.

10. Load the program into device memory.

11. Set breakpoint at the main() function.

12. Run the program and stop at the main() function.

13. Remove the breakpoint at the main() function.

14. Step into the first line of the main() function. Else gdb will complain about entry macros file missing.

15. TODO: Write program to flash memory so that it becomes permanent.

How This Rust Crate Was Created

1. Install Cargo clone and add subcommands:

   cargo install cargo-clone
   cargo install cargo-edit

2. Clone the quickstart crate

   cargo clone cortex-m-quickstart && cd $_

3. Change the crate name, author and version in Cargo.toml:

   [package]
   authors = ["Jorge Aparicio <[email protected]>"]
   name = "demo"
   version = "0.1.0"

4. Specify the memory layout of the target device. Since board support crate for stm32f103xx provides this file, we remove both the memory.x and build.rs files.

   rm memory.x build.rs

5. Set a default build target

   cat >>.cargo/config <<'EOF'
   
   [build]
   target = "thumbv7m-none-eabi"
   EOF

6. Depend on a HAL implementation.

   cargo add https://github.com/japaric/stm32f103xx
   cargo add https://github.com/japaric/stm32f103xx-hal

7. Copy the delay sample application from https://github.com/japaric/stm32f103xx-hal into src\main.rs

   rm -r src/* && cp ../stm32f103xx_hal/examples/delay.rs src/main.rs

References

Windows Setup for Embedded Rust: https://japaric.github.io/discovery/03-setup/windows.html

Peripheral I/O with Embedded HAL: http://blog.japaric.io/brave-new-io/

Embedded Rust Blog: http://blog.japaric.io/

Embedded Rust Book (work in progress): https://github.com/rust-lang-nursery/embedded-wg/tree/master/books/embedded-rust-book

Rust RTFM Docs and Book (work in progress): https://github.com/japaric/cortex-m-rtfm/tree/gh-pages

Awesome Embedded Rust (covers other hardware platforms): https://github.com/rust-embedded/awesome-embedded-rust

Details of rustup: https://github.com/rust-lang-nursery/rustup.rs

STM32F103C8 Website: https://www.st.com/en/microcontrollers/stm32f103c8.html

STM32F103C8 Datasheet: https://www.st.com/resource/en/datasheet/stm32f103c8.pdf

STM32F103C8 Reference Manual: https://www.st.com/content/ccc/resource/technical/document/reference_manual/59/b9/ba/7f/11/af/43/d5/CD00171190.pdf/files/CD00171190.pdf/jcr:content/translations/en.CD00171190.pdf

STM32F103C8 Flash Programming: https://www.st.com/content/ccc/resource/technical/document/programming_manual/10/98/e8/d4/2b/51/4b/f5/CD00283419.pdf/files/CD00283419.pdf/jcr:content/translations/en.CD00283419.pdf

STM32F103C8 ARM Cortex M3 Programming: https://www.st.com/content/ccc/resource/technical/document/programming_manual/5b/ca/8d/83/56/7f/40/08/CD00228163.pdf/files/CD00228163.pdf/jcr:content/translations/en.CD00228163.pdf

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)

• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.