5 spi通信时钟线不正常

发布于 2022-05-05 22:10:23 浏览：475 订阅该版

5 个回答

crystal266 2022-05-06

嵌入式

用的什么芯片？stm32 使用 spi 需要使用 CubeMX 对 spi 的 CLK、MISO、MOSI 三个引脚的复用功能进行配置，配置后会生成 `HAL_SPI_MspInit` 函数，这个函数对 spi 的引脚的复用功能进行了初始化。在使用时使用方法如下，也可以参考文章 [使用RT-Thread studio开启SPI框架驱动OLED](https://club.rt-thread.org/ask/question/365b0e76ddd49b3f.html)

和下面的代码对照一下，看看是不是有不同的地方
```c
{
    struct rt_spi_device* spi_dev;
    struct rt_spi_configuration cfg;
    
    __HAL_RCC_GPIOA_CLK_ENABLE();    // 使能时钟
    
    //设备挂载到SPI总线，抽象为 spi10 设备，同时使用时还需进行 rt_spi_configure
    rt_hw_spi_device_attach("spi1", "spi10", GPIOA, GPIO_PIN_15);
    
    spi_dev= (struct rt_spi_device *)rt_device_find("spi10");
    if (!spi_dev)
    {
        rt_kprintf("spi sample run failed! can't find %s device!\n", "spi10");
    }
    else
    {
        // owner必须配置,因为默认为空,为空时无法进行初始化操作
        spi_dev->bus->owner = spi_dev; // 必须!!!

// 配置spi
        cfg.data_width = 8;
        cfg.mode = RT_SPI_MASTER | RT_SPI_MODE_3 | RT_SPI_MSB;  // 主机,模式0,高位在前
        cfg.max_hz = 20 * 1000 * 1000; // SPI 接口时钟频率
        rt_spi_configure(spi_dev, &cfg); // 此时才进行MspInit相关的时钟及IO口初始化
    }
}
```

crystal266 2022-05-06

嵌入式

另外附上 spi 驱动的调用过程

```c
rt_hw_spi_init                                  /* drivers/drv_spi.c */
    |-> stm32_get_dma_info                      /* drivers/drv_spi.c */
    |-> rt_hw_spi_bus_init                      /* rt_hw_spi_bus_init */
        |-> rt_spi_bus_register                 /* rt-thread/components/drivers/spi/spi_core.c */
            |-> rt_spi_bus_device_init          /* rt-thread/components/drivers/spi/spi_dev.c */
                |-> rt_device_register          /* rt-thread/src/device.c */
                    |-> rt_object_init          /* rt-thread/src/object.c */
rt_hw_spi_device_attach
    |-> rt_spi_bus_attach_device
        |-> rt_device_find
        |-> rt_spidev_device_init
            |-> rt_device_register

static const struct rt_spi_ops stm_spi_ops =
{
    .configure = spi_configure,
    .xfer = spixfer,
};
       
rt_spi_configure                                /* rt-thread/components/drivers/spi/spi_core.c */
    |-> device->bus->ops->configure             /* rt-thread/components/drivers/spi/spi_core.c */
        |-> spi_configure                       /* drivers/drv_spi.c */
            |-> stm32_spi_init                  /* drivers/drv_spi.c */
                |-> HAL_SPI_Init                /* libraries/STM32F4xx_HAL_Driver/Src/stm32f4xx_hal_spi.c */
                    |-> HAL_SPI_MspInit         /* 硬件管脚复用初始化 cubemx/Src/stm32f4xx_hal_msp.c */
```