RT-Thread-【NXP-MCXA156】恩智浦A156上的 IIC(硬件) 实践RT-Thread问答社区

【NXP-MCXA156】恩智浦A156上的 IIC(硬件) 实践

发布于 2025-02-28 23:34:57 浏览：19 订阅该版

[tocm]

# 写在前面
关于恩智浦156开发板的介绍、上手以及代码仓信息，官方已经写的很具体了，详见[NXP FRDM-MCXA156 上手指南](https://www.rt-thread.org/document/site/#/rt-thread-version/rt-thread-standard/tutorial/quick-start/frdm_mcxa156/quick-start "NXP FRDM-MCXA156 上手指南")。env工具使用最新的2.0.0版，官网下载即可。
相关的PCB原理图以及芯片使用手册，详见G39OL1的[【FRDM-MCXA156测评】- UART模块](https://club.rt-thread.org/ask/article/ab4e9d33f2423a7c.html "【FRDM-MCXA156测评】- UART模块")，这里不再赘述。
# 一、实现内容
使用硬件I2C驱动SSD1306模块，根据原理图选择P3_27(I2C3_SCL)、P3_28(I2C3_SDA)作为控制引脚，进行u8g2以及SSD1306驱动测试。
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/40cbd65b1ee13ff8731ce879f5438a90.png.webp)
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/4219a8fa29c3f270bedc6663116336c6.png.webp)
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/ce2e22e056543b103bcbea60f9ef8297.png.webp)
# 二、引脚配置
找到\RT-Thread\rt-thread\bsp\nxp\mcx\mcxa\frdm-mcxa156\board\MCUX_Config\board路径下的pin_mux.c，添加如下引脚配置代码，这里把BSP_USING_I2C3宏也加入，后面改一下Kconfig，就可以使用ENV工具自由配置了。

```c
#ifdef BSP_USING_I2C3
/* LPI2C3 peripheral is released from reset */
    RESET_ReleasePeripheralReset(kLPI2C0_RST_SHIFT_RSTn);
    const port_pin_config_t port3_28_pin51_config = {/* Internal pull-up resistor is enabled */
                                                     .pullSelect = kPORT_PullUp,
                                                     /* Low internal pull resistor value is selected. */
                                                     .pullValueSelect = kPORT_LowPullResistor,
                                                     /* Fast slew rate is configured */
                                                     .slewRate = kPORT_FastSlewRate,
                                                     /* Passive input filter is disabled */
                                                     .passiveFilterEnable = kPORT_PassiveFilterDisable,
                                                     /* Open drain output is disabled */
                                                     .openDrainEnable = kPORT_OpenDrainDisable,
                                                     /* Low drive strength is configured */
                                                     .driveStrength = kPORT_LowDriveStrength,
                                                     /* Normal drive strength is configured */
                                                     .driveStrength1 = kPORT_NormalDriveStrength,
                                                     /* Pin is configured as LPI2C3_SDA */
                                                     .mux = kPORT_MuxAlt2,
                                                     /* Digital input enabled */
                                                     .inputBuffer = kPORT_InputBufferEnable,
                                                     /* Digital input is not inverted */
                                                     .invertInput = kPORT_InputNormal,
                                                     /* Pin Control Register fields [15:0] are not locked */
                                                     .lockRegister = kPORT_UnlockRegister};
    /* PORT3_28 (pin 51) is configured as LPI2C3_SCL */
    PORT_SetPinConfig(PORT3, 28U, &port3_28_pin51_config);
    const port_pin_config_t port3_27_pin52_config = {/* Internal pull-up resistor is enabled */
                                                     .pullSelect = kPORT_PullUp,
                                                     /* Low internal pull resistor value is selected. */
                                                     .pullValueSelect = kPORT_LowPullResistor,
                                                     /* Fast slew rate is configured */
                                                     .slewRate = kPORT_FastSlewRate,
                                                     /* Passive input filter is disabled */
                                                     .passiveFilterEnable = kPORT_PassiveFilterDisable,
                                                     /* Open drain output is disabled */
                                                     .openDrainEnable = kPORT_OpenDrainDisable,
                                                     /* Low drive strength is configured */
                                                     .driveStrength = kPORT_LowDriveStrength,
                                                     /* Normal drive strength is configured */
                                                     .driveStrength1 = kPORT_NormalDriveStrength,
                                                     /* Pin is configured as LPI2C3_SCL */
                                                     .mux = kPORT_MuxAlt2,
                                                     /* Digital input enabled */
                                                     .inputBuffer = kPORT_InputBufferEnable,
                                                     /* Digital input is not inverted */
                                                     .invertInput = kPORT_InputNormal,
                                                     /* Pin Control Register fields [15:0] are not locked */
                                                     .lockRegister = kPORT_UnlockRegister};
    /* PORT3_27 (pin 52) is configured as LPI2C3_SCL */
    PORT_SetPinConfig(PORT3, 27U, &port3_27_pin52_config);
#endif
```
同路径下的Kconfig增加I2C3的描述，如下图所示

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/dd8a0148ec6eee2b8ddf7c6757bfec0a.png)
# 四、ENV配置
进入ENV后，输入menuconfig进入配置界面，首先在板级支持内容下，开启I2C3，如下图所示

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/c41d0046ac1fffd877eee018a84ffedd.png.webp)
然后在驱动框架下开启I2C设备

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/dd6fe8536c95de7b190d394f9fe0ada9.png.webp)
启用U8G2驱动包以及其测试例程，如下图所示，这里选择I2C3作为驱动外设：

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/3609f9260d411abfa4c8714f9312cd93.png.webp)
启用SSD1306驱动包以及其测试例程，如下图所示，这里同样选择I2C3作为驱动外设：

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/14460211ea968cc1c8193e13a5642729.png.webp)
官方提供的drv_i2c驱动里只有一个I2C0的例子，简单补充下I2C3的内容，详细代码如下：
```c
struct lpc_i2c_bus lpc_obj[] =
{
#ifdef BSP_USING_I2C0
        {
            .I2C = LPI2C0,
            .baud = 100000U,
            .clock_attach_id = kFRO12M_to_LPI2C0,
            .clock_div_name = kCLOCK_DivLPI2C0,
            .clock_src = kCLOCK_Fro12M,
            .name = "i2c0",
        },
#endif

#ifdef BSP_USING_I2C3
        {
            .I2C = LPI2C3,
            .baud = 100000U,
            .clock_attach_id = kFRO12M_to_LPI2C3,
            .clock_div_name = kCLOCK_DivLPI2C3,
            .clock_src = kCLOCK_Fro12M,
            .name = "i2c3",
        },
#endif
};
```
然后保存退出配置界面，使用pkgs --update指令获取驱动包，如下图所示

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/6ce51ca39f1ea648e25959692696ab7c.png)
最后使用scons --target=mdk5生成keil工程。
打开工程，开始编译，会提示#include <_ansi.h>不存在，详细的解决方法参照[@出出啊](/u/db779ee1aa856f55)的问题答复[v4.1.1 ENV里使能SSD1306,需要包含_ansi.h头文件。找不到](https://club.rt-thread.org/ask/question/2da5e09a365aa04f.html "v4.1.1 ENV里使能SSD1306,需要包含_ansi.h头文件。找不到")，参照问题答复修改后即可编译通过。
下载到开发板后开始测试。
# 五、开始测试
连接到终端后，使用Table建可以看到u8g2以及SSD1306的测试代码内容，如下如所示

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/918c6d47ba81c622c36bbdb0ee0a1c68.png)
使用list device指令可以看到I2C3已经注册成功

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/2126881517fbaba8cd316101cd4b071e.png)
首先测试u8g2的测试，在终端输入u8g2_ssd1306_12864_hw_i2c_example进行u8g2测试，可以看到屏幕上出现了RTTHREAD和😀

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/310ecb551bfc4e4aa2ad14645f0a959f.png.webp)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/607c972aa32124ae5d82f200ad61b5a3.png.webp)
最后进行SSD1306的测试，在终端输入ssd1306_TestAll，即可开始一系列刷屏的测试。

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/94bd79d3b1f4cfbf451588d811aaeb5f.png.webp)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/09ea1ec66924d363fb7a204049501748.png.webp)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/2ef60dfcf548349138eb25fe88f54513.png.webp)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/bc7df0aca6e51e222118dbb7d7a0c16b.png.webp)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/92eaa85fdedd55534d5880aa919db124.png.webp)
至此I2C3硬件测试及实践内容完成。
# 六、心得体会
本次测试内容为恩智浦A156上的 IIC(硬件) 实践，除了增加I2C3的引脚配置以及Kconfig的内容，其它代码基本没有手敲，官方的软件包已经很到位了，希望后面官方可以把恩智浦的可视化配置工具集成到rtthread studio中。总的来说恩智浦A156+RT-Thread+env的开发模式相对简单、很容易上手。
因本人水平有限，文章内容及代码中可能会出现错误，还请谅解。