前言

最近接触到 rust，鼓吹安全性和现代语言，宣称有接近 C 的性能，并且可以用于嵌入式开发，我比较感兴趣，遂上手试试。

开发环境

安装VSCode

https://code.visualstudio.com

VSCode插件：

• Chinese (Simplified) (简体中文)
• rust-analyzer
• Even Better TOML
• Error Lens
• Debugger for probe-rs
• crates
• C/C++

安装Rust

rust程序

https://www.rust-lang.org/

中文文档

https://xxchang.github.io/book/intro/install.html

rust 下载 exe 后，默认安装就行了，不需要安装 nightly 版本

更新与卸载：

rustup update
rustup self uninstall

更换源，不然下载包特别慢，配置国内镜像，在用户名.cargo\config.toml下新增或新建以下内容：

[source.crates-io]
replace-with='rsproxy'
[source.rsproxy]
registry="https://rsproxy.cn/crates.io-index"
[registries.rsproxy]
index = "https://rsproxy.cn/crates.io-index"
[net]
git-fetch-with-cli = true

如果想使用 nightly 版本，可以像下面这样：

rustc --version
rustup install nightly
rustup default nightly

安装编译支持：

cargo install cargo-binutils
rustup component add llvm-tools-preview
cargo install cargo-generate

安装架构，看你 mcu 是什么架构，我这里选择 thumbv7em-none-eabihf：

rustup target add thumbv6m-none-eabi     # 对于Cortex-M0/M0+/M1
rustup target add thumbv7m-none-eabi     # 对于Cortex-M3
rustup target add thumbv7em-none-eabi    # 对于Cortex-M4/M7（不带硬件浮点）
rustup target add thumbv7em-none-eabihf  # 对于Cortex-M4F/M7F（带硬件浮点）
rustup target add thumbv8m.base-none-eabi # 对于Cortex-M23
rustup target add thumbv8m.main-none-eabi # 对于Cortex-M33（不带硬件浮点）
rustup target add thumbv8m.main-none-eabihf # 对于Cortex-M33（带硬件浮点）

rustup target add riscv64gc-unknown-none-elf # 对于RISC-V 64bit
rustup target add riscv32imac-unknown-none-elf # 对于RISC-V 32bit

安装 probe-rs 工具：

git clone https://github.com/probe-rs/probe-rs.git
cd probe-rs
cargo build --release --features cli # 生成的工具拷贝到 cargo 目录
probe-rs chip list | grep -i gd32f427 # 不支持本芯片
target-gen.exe pack .\GigaDevice.GD32F4xx_DFP.3.1.0.pack .\ # 生成 yaml 文件，拷贝到工程 targets 目录，重新编译
probe-rs chip info GD32F427VK
probe-rs list # 列出连接的调试器
probe-rs info --probe 28e9:058f # 检测目标芯片信息 检测不到
probe-rs reset --probe 28e9:058f --chip GD32F427VK # 可以复位芯片
probe-rs read b32 0x08000000 2 --chip gd32f427vk --probe 28e9:058f # 可以读取信息

到目前为止，该安装的环境已经安装完成了，可以进行开发了。

开发

开发 gd32f427vkt6，发现没有对应的芯片支持：

查看芯片支持

cargo search gd32f4
gd32f4 = "0.1.0-alpha.1"    # Device support crates for GD32F4 devices

创建工程：

cargo generate --git https://github.com/rust-embedded/cortex-m-quickstart
Project Name: hello_rust

生成 pac 库，在 hello_rust 同级目录下：

cargo install svd2rust
cargo install form
cargo new --lib gd32f4xx-pac
cd .\gd32f4xx-pac\ # 手动删除 src 目录
svd2rust -i GD32F4xx.svd
form -i lib.rs -o src/ # 手动删除 svd2rust 生成的 lib.rs
cargo fmt

在 .cargo\config.toml 文件，启用目标架构，我的是：

target = "thumbv7em-none-eabihf"     # Cortex-M4F and Cortex-M7F (with FPU)

在 .vscode\launch.json 文件，增加调试内容：

{
    "type": "probe-rs-debug",
    "request": "launch",
    "name": "probe-rs Test",
    "cwd": "",
    //!MODIFY (or remove)
    "speed": 24000,
    //!MODIFY (or remove)
    "probe": "28e9:058f",
    "runtimeExecutable": "probe-rs",
    "runtimeArgs": ["dap-server"],
    "connectUnderReset": false,
    "chip": "GD32F427VK",
    "flashingConfig": {
        "flashingEnabled": true,
        "haltAfterReset": true
    },
    "coreConfigs": [
        {
            "coreIndex": 0,
            "programBinary": "./target/thumbv7em-none-eabihf/debug/hello-rust"
        }
    ]
},

src\main.rs 内容如下：

#![no_std]
#![no_main]

// pick a panicking behavior
use panic_halt as _; // you can put a breakpoint on `rust_begin_unwind` to catch panics
                      // use panic_abort as _; // requires nightly
                      // use panic_itm as _; // logs messages over ITM; requires ITM support
                      // use panic_semihosting as _; // logs messages to the host stderr; requires a debugger

use cortex_m::asm;
use cortex_m_rt::entry;

#[allow(unused_imports)]
use cortex_m::delay::Delay;
#[allow(unused_imports)]
use gd32f4xx_pac::Peripherals;
use rtt_target::{rprintln, rtt_init_print};

#[entry]
fn main() -> ! {
    asm::nop(); // To not have main optimize to abort in release mode, remove when you add code

    let periph = Peripherals::take().unwrap();
    let rcu = periph.RCU;

    // - enable the led clock, GPIOC
    rcu.ahb1en().modify(|_, w| w.pcen().set_bit());

    // - configure led GPIO port
    //   LED = PA1
    let led = periph.GPIOC;
    // #define GPIO_MODE_INPUT            CTL_CLTR(0)           /*!< input mode */
    // #define GPIO_MODE_OUTPUT           CTL_CLTR(1)           /*!< output mode */
    // #define GPIO_MODE_AF               CTL_CLTR(2)           /*!< alternate function mode */
    // #define GPIO_MODE_ANALOG           CTL_CLTR(3)           /*!< analog mode */
    //   MODE = OUTPUT
    led.ctl().modify(|_, w| unsafe { w.ctl6().bits(1) });
    // GPIO_PUPD_NONE = 0
    // GPIO_PUPD_PULLUP = 1
    // GPIO_PUPD_PULLDOWN = 2
    led.pud().modify(|_, w| unsafe { w.pud6().bits(0) });
    //   OMODE = 0, PushPull
    led.omode().modify(|_, w| w.om6().clear_bit());

    // gpio pin output speed: over GPIO_OSPEED_50MHZ
    led.ospd().modify(|_, w| unsafe { w.ospd6().bits(0x03) });

    led.bop().write(|w| w.bop6().set_bit());
    // gpioa.bc().write(|w| w.cr6().set_bit());

    let core = cortex_m::Peripherals::take().unwrap();
    let systick = core.SYST;
    let mut delay = Delay::new(systick, 16_000_000);

    rtt_init_print!(); // 初始化RTT

    let mut no = 0;

    loop {
        delay.delay_ms(1_000);

        led.tg().write(|w| w.tg6().set_bit());
        rprintln!("hello rust on gd32f427v-start:{}", no);
        no += 1;
        // panic!("Oops");
    }
}

memory.x 文件内容如下：

MEMORY
{
  /* NOTE 1 K = 1 KiBi = 1024 bytes */
  /* TODO Adjust these memory regions to match your device memory layout */
  /* These values correspond to the LM3S6965, one of the few devices QEMU can emulate */
  FLASH : ORIGIN = 0x08000000, LENGTH = 256K
  RAM : ORIGIN = 0x20000000, LENGTH = 64K
}

/* This is where the call stack will be allocated. */
/* The stack is of the full descending type. */
/* You may want to use this variable to locate the call stack and static
    variables in different memory regions. Below is shown the default value */
/* _stack_start = ORIGIN(RAM) + LENGTH(RAM); */

/* You can use this symbol to customize the location of the .text section */
/* If omitted the .text section will be placed right after the .vector_table
    section */
/* This is required only on microcontrollers that store some configuration right
    after the vector table */
/* _stext = ORIGIN(FLASH) + 0x400; */

/* Example of putting non-initialized variables into custom RAM locations. */
/* This assumes you have defined a region RAM2 above, and in the Rust
    sources added the attribute `#[link_section = ".ram2bss"]` to the data
    you want to place there. */
/* Note that the section will not be zero-initialized by the runtime! */
/* SECTIONS {
      .ram2bss (NOLOAD) : ALIGN(4) {
        *(.ram2bss);
        . = ALIGN(4);
      } > RAM2
    } INSERT AFTER .bss;
*/

REGION_ALIAS("REGION_TEXT", FLASH);
REGION_ALIAS("REGION_RODATA", FLASH);
REGION_ALIAS("REGION_DATA", RAM);
REGION_ALIAS("REGION_BSS", RAM);
REGION_ALIAS("REGION_HEAP", RAM);
REGION_ALIAS("REGION_STACK", RAM);

编译：

cargo build --release # 发布版本
cargo objcopy --release -- -O binary firmware.bin

cargo build # debug 版本
cargo objcopy -- -O binary firmware.bin

下载、调试：

probe-rs run --probe 28e9:058f --chip GD32F427vk .\target\thumbv7m-none-eabi\release\hello-rust

上面的代码功能为 点灯+rtt 打印，我发现进行代码调试的时候，没有 rtt 打印信息，上图：

脱机跑就会有打印信息，上图：

结语

踩了很多坑，对我启发比较大的是本站的 gd32f310 开发板评测的一位大佬的帖子，可惜在本站上没找到，是在其他站点转载看到的，非常感谢各位先行的前辈。

总的来说，这次体验是不错的，新增不支持的芯片比较快捷，只不过 pac 编程还得看手册，是比较麻烦的，希望诸多厂家把社区搞起来，hal 丰富起来了，咱们才方便不是吗。