rt thread spi 使用

发布于 2019-07-17 09:59:15 浏览：2001 订阅该版

有没有尝试按照rt thread 官方文档的spi 案例敲代码，但是发现总线错误或者spi数据传输不成功的情况，那么下面可以看一下我的记录。

```#include <rtthread.h>
#include <rtdevice.h>
#include "drv_spi.h"                     //注意添加这个头文件，不然rt_hw_spi_device_attach 无法调用

#define    FLASH_DEVICE_NAME   "spi12"

struct rt_spi_device *spi_dev_flash;

struct rt_spi_message msg1, msg2;

struct rt_spi_message *res;

struct rt_spi_configuration cfg;

rt_uint8_t flash_id[] = {0x90, 0x24};

//文档中提示使用rt_hw_spi_device_attach这个函数，但是没有码
static int rt_hw_spi_flash_init(void)
{
   __HAL_RCC_GPIOC_CLK_ENABLE();
	 rt_hw_spi_device_attach("spi1", "spi12", GPIOC, GPIO_PIN_0);           //我用的野火指南者开发板，CS片选引脚为PC0
	 return RT_EOK;
}

//测试代码，直接放在main 中了
int main(void)
{   
	  //挂载spi12 到 spi1
	  rt_hw_spi_flash_init();  
	
	  spi_dev_flash = (struct rt_spi_device *)rt_device_find(FLASH_DEVICE_NAME);
	
	  if(spi_dev_flash != RT_NULL)
		{
		   rt_kprintf("find the flash on the spi bus<br>");
		}
		else
		{
		   rt_kprintf("can't find the device<br>");
		}
		
		//配置spi
		cfg.data_width = 8;
		cfg.mode = RT_SPI_MASTER | RT_SPI_MODE_0 | RT_SPI_MSB;
		cfg.max_hz = 20*1000*1000;   //20Mhz
		
	  rt_spi_configure(spi_dev_flash, &cfg);
		
		    //向设备发送数据
        msg1.send_buf   = &flash_id[0];
        msg1.recv_buf   = RT_NULL;
        msg1.length     = 1;
        msg1.cs_take    = 1;
        msg1.cs_release = 0;
        msg1.next       = &msg2;
		
		    msg2.send_buf   = &flash_id[1];
		    msg2.recv_buf   = RT_NULL;
		    msg2.length     = 1;
		    msg2.cs_take    = 0;
		    msg2.cs_release = 1;
				msg2.next       = RT_NULL;
     		
	      res =   rt_spi_transfer_message(spi_dev_flash, &msg1);   
		    
		    if(res == RT_NULL)
				{
				   rt_kprintf("data transfer ok from spi12<br>");
				}
		
   return 0;
}

```最后的输出结果如下：
![24 (2).png](/uploads/201907/17/095625bkn5o7zlknkwluoo.png)

0x90， 可以发现上面设置的20Mhz  是 spi 数据传输时的，clk 频率。
![24 (1).png](/uploads/201907/17/095749ipcdqqhh4xhxi41h.png)
0x24

spi12 设备 工作正常。