在FRDM-MCXA366工程内 修改main函数 添加uart_int_sample程序，实现串口的交互。在BOARD_InitPins…

[chen13587]

…函数内添加串口3的引脚初始化代码

拉取/合并请求描述：(PR description)

为什么提交这份PR (why to submit this PR)

在 FRDM-MCXA366 开发板上，串口3（UART3）的引脚尚未初始化，导致该串口无法正常使用。本次提交补充了 UART3 的引脚初始化代码，使开发者可以直接使用 uart3 设备进行调试或通信。

你的解决方案是什么 (what is your solution)

在 bsp\nxp\mcx\mcxa\frdm-mcxa366\board\MCUX_Config\board\pin_mux.c 的 BOARD_InitPins() 函数内，增加了 UART3 的 TX和 RX引脚的功能配置，调用 MCXA366 的 库函数进行初始化。同时确保该配置仅在 #define BSP_USING_UART3 宏启用时生效。

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

• BSP: bsp/nxp/frdm-mcxa366

• .config: CONFIG_BSP_USING_UART3=y

• BSP:

• .config:

• action:

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formatting 等源码格式化工具确保格式符合RT-Thread代码规范 This PR complies with RT-Thread code specification
• 如果是新增bsp, 已经添加ci检查到.github/ALL_BSP_COMPILE.json 详细请参考链接BSP自查

[CLAassistant]

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[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）。
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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_mcxa

Reviewers: @hywing

Changed Files (Click to expand)

• bsp/nxp/mcx/mcxa/frdm-mcxa366/.ci/attachconfig/ci.attachconfig.yml
• bsp/nxp/mcx/mcxa/frdm-mcxa366/.config
• bsp/nxp/mcx/mcxa/frdm-mcxa366/RTE/Device/MCXA366VLQ/MCXA.dbgconf
• bsp/nxp/mcx/mcxa/frdm-mcxa366/RTE/Device/MCXA366VLQ/MCXA.dbgconf.base@0.0.0
• bsp/nxp/mcx/mcxa/frdm-mcxa366/RTE/Device/MCXA366VPN/MCXA.dbgconf
• bsp/nxp/mcx/mcxa/frdm-mcxa366/RTE/Device/MCXA366VPN/MCXA.dbgconf.base@0.0.0
• bsp/nxp/mcx/mcxa/frdm-mcxa366/applications/main.c
• bsp/nxp/mcx/mcxa/frdm-mcxa366/board/MCUX_Config/board/pin_mux.c
• bsp/nxp/mcx/mcxa/frdm-mcxa366/project.uvoptx
• bsp/nxp/mcx/mcxa/frdm-mcxa366/project.uvprojx
• bsp/nxp/mcx/mcxa/frdm-mcxa366/rtconfig.h

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📊 Current Review Status (Last Updated: 2026-07-04 20:20 CST)

• ⌛ @hywing Pending Review

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📝 Review Instructions

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   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.

[CYFS3]

A366原本的调式的串口是可以用的，你这边说的串口三是做什么作用？