[bsp/stm32] add STM32F103C6 support for stm32f103-blue-pill

[avm1234567]

拉取/合并请求描述：(PR description)

[

为什么提交这份PR (why to submit this PR)

The stm32f103-blue-pill BSP previously only supported the STM32F103C8 chip (64KB/128KB Flash, 20KB RAM).
However, many Blue Pill development boards on the market come equipped with the lower-cost STM32F103C6 variant
(32KB Flash, 10KB RAM). This PR adds STM32F103C6 support to the Blue Pill BSP while maintaining 100% backward
compatibility for the default C8 variant.

你的解决方案是什么 (what is your solution)

1. **Kconfig (`bsp/stm32/stm32f103-blue-pill/Kconfig`)**:
   - Added a `choice` for target SOC: `SOC_STM32F103C8` (default) and `SOC_STM32F103C6`.
   - Selecting `SOC_STM32F103C6` automatically selects `RT_USING_SMALL_MEM`, `RT_USING_SMALL_MEM_AS_HEAP`, and

RT_KLIBC_USING_LIBC_VSSCANF to optimize memory and prevent linking heavy double-precision float libraries.
2. Dynamic Memory Boundary (board/board.h):
- Dynamically defines STM32_FLASH_SIZE (32KB for C6 vs 128KB for C8) and STM32_SRAM_SIZE (10KB for C6 vs
20KB for C8), accurately bounding HEAP_END at 0x20002800 for C6 to prevent runtime heap corruption.
3. Peripheral Constraints (board/Kconfig):
- Guarded peripherals that do not physically exist on C6 (USART3, SPI2) and RTduino with depends on !SOC_STM32F103C6. Added BSP_USING_SPI1.
4. Linker Script & Optimization (board/linker_scripts/link.lds & rtconfig.py):
- Updated GNU ld linker script with dynamic _ROM_SIZE and _RAM_SIZE symbols with default fallbacks.
- In rtconfig.py, conditionally pass --defsym=_ROM_SIZE=32k,--defsym=_RAM_SIZE=10k and -Os optimization
for C6 builds.
5. Documentation (README.md & README_zh.md):
- Added step-by-step instructions in English and Chinese on how to configure and build for STM32F103C6 using
menuconfig.

请提供验证的bsp和config (provide the config and bsp)

• BSP:bsp/stm32/stm32f103-blue-pill

• .config:
  CONFIG_SOC_STM32F103C6=y
  CONFIG_RT_USING_SMALL_MEM=y
  CONFIG_RT_USING_SMALL_MEM_AS_HEAP=y
  CONFIG_RT_KLIBC_USING_LIBC_VSSCANF=y
  # CONFIG_RT_USING_DEBUG is not set
  # CONFIG_RT_USING_EVENT is not set
  # CONFIG_RT_USING_MAILBOX is not set
  # CONFIG_RT_USING_MESSAGEQUEUE is not set
  # CONFIG_RT_SERIAL_USING_DMA is not set
  # CONFIG_FINSH_USING_DESCRIPTION is not set
  # CONFIG_FINSH_USING_OPTION_COMPLETION is not set
  CONFIG_FINSH_THREAD_STACK_SIZE=2048

• action: https://github.com/avm1234567/rt-thread/actions

]

当前拉取/合并请求的状态 Intent for your PR

必须选择一项 Choose one (Mandatory):

[✓ ] 本拉取/合并请求是一个草稿版本 This PR is for a code-review and is intended to get feedback
[✓] 本拉取/合并请求是一个成熟版本 This PR is mature, and ready to be integrated into the repo

代码质量 Code Quality：

我在这个拉取/合并请求中已经考虑了 As part of this pull request, I've considered the following:

[✓] 已经仔细查看过代码改动的对比 Already check the difference between PR and old code
[✓] 代码风格正确，包括缩进空格，命名及其他风格 Style guide is adhered to, including spacing, naming and other
styles
[✓] 没有垃圾代码，代码尽量精简，不包含#if 0代码，不包含已经被注释了的代码 All redundant code is removed and cleaned
up
[✓] 所有变更均有原因及合理的，并且不会影响到其他软件组件代码或BSP All modifications are justified and not affect
other components or BSP
[✓] 对难懂代码均提供对应的注释 I've commented appropriately where code is tricky
[✓] 代码是高质量的 Code in this PR is of high quality
[✓] 已经使用clang-format https://clang.llvm.org/docs/ClangFormat.html 源码格式化工具确保格式符合RT-Thread代码规范
https://github.com/RT-Thread/rt-thread/blob/master/documentation/7.contribution/coding_style_cn.md This PR has been
formatted with clang-format and complies with RT-Thread code specification https://github.com/RT-Thread/rt-
thread/blob/master/documentation/7.contribution/coding_style_en.md
[ ] 如果是新增bsp, 已经添加ci检查到.github/ALL_BSP_COMPILE.json https://github.com/RT-Thread/rt-
thread/blob/master/.github/ALL_BSP_COMPILE.json 详细请参考链接BSP自查 https://www.rt-thread.org/document/site/#/rt-
thread-version/rt-thread-standard/development-guide/bsp-selfcheck/bsp_selfcheck

[github-actions]

👋 感谢您对 RT-Thread 的贡献！Thank you for your contribution to RT-Thread!

为确保代码符合 RT-Thread 的编码规范，请在你的仓库中执行以下步骤运行代码格式化工作流（如果格式化CI运行失败）。
To ensure your code complies with RT-Thread's coding style, please run the code formatting workflow by following the steps below (If the formatting of CI fails to run).

---

🛠 操作步骤 | Steps

1. 前往 Actions 页面 | Go to the Actions page
   点击进入工作流 → | Click to open workflow →

2. 点击 Run workflow | Click Run workflow

• Use workflow from 保持默认分支（通常为 master）
  Keep the default branch (usually master) in Use workflow from
• 在 branch 输入框填写 PR 分支 feat/bluepill-stm32f103c6
  Enter PR branch feat/bluepill-stm32f103c6 in the branch field
• 设置需排除的文件/目录（目录请以"/"结尾）
  Set files/directories to exclude (directories should end with "/")

3. 等待工作流完成 | Wait for the workflow to complete
   格式化后的代码将作为独立提交推送至你的分支。
   The formatting changes will be pushed to your branch as a separate commit.

完成后，提交将自动更新至 feat/bluepill-stm32f103c6 分支，关联的 Pull Request 也会同步更新。
Once completed, commits will be pushed to the feat/bluepill-stm32f103c6 branch automatically, and the related Pull Request will be updated.

如有问题欢迎联系我们，再次感谢您的贡献！💐
If you have any questions, feel free to reach out. Thanks again for your contribution!

[github-actions]

📌 Code Review Assignment

🏷️ Tag: bsp_stm32

Reviewers: @Liang1795 @hamburger-os @wdfk-prog

Changed Files (Click to expand)

• bsp/stm32/stm32f103-blue-pill/Kconfig
• bsp/stm32/stm32f103-blue-pill/README.md
• bsp/stm32/stm32f103-blue-pill/README_zh.md
• bsp/stm32/stm32f103-blue-pill/board/Kconfig
• bsp/stm32/stm32f103-blue-pill/board/board.h
• bsp/stm32/stm32f103-blue-pill/board/linker_scripts/link.lds
• bsp/stm32/stm32f103-blue-pill/rtconfig.py

🏷️ Tag: bsp_stm32f103-blue-pill

Reviewers: @Liang1795

Changed Files (Click to expand)

• bsp/stm32/stm32f103-blue-pill/Kconfig
• bsp/stm32/stm32f103-blue-pill/README.md
• bsp/stm32/stm32f103-blue-pill/README_zh.md
• bsp/stm32/stm32f103-blue-pill/board/Kconfig
• bsp/stm32/stm32f103-blue-pill/board/board.h
• bsp/stm32/stm32f103-blue-pill/board/linker_scripts/link.lds
• bsp/stm32/stm32f103-blue-pill/rtconfig.py

---

📊 Current Review Status (Last Updated: 2026-10-02 15:07 CST)

• ⌛ @Liang1795 Pending Review
• ⌛ @hamburger-os Pending Review
• ⌛ @wdfk-prog Pending Review

---

📝 Review Instructions

1. 维护者可以通过单击此处来刷新审查状态: 🔄 刷新状态
   Maintainers can refresh the review status by clicking here: 🔄 Refresh Status

2. 确认审核通过后评论 LGTM/lgtm
   Comment LGTM/lgtm after confirming approval

3. PR合并前需至少一位维护者确认
   PR must be confirmed by at least one maintainer before merging

ℹ️ 刷新CI状态操作需要具备仓库写入权限。
ℹ️ Refresh CI status operation requires repository Write permission.