为什么移植了IIC协议，有数据输出，但是线程会卡死？

发布于 2018-06-14 14:34:58 浏览：1930 订阅该版

* 本帖最后由 aozima 于 2018-6-14 20:24 编辑 *

```
#include "lm75a.h"
#include <rtdef.h>
rt_int32_t swm_get_scl(void *data)
{
	IIC_CLK_IN;
	return (rt_int32_t)GPIO_GetBit(GPIOB,PIN13);
}
rt_int32_t swm_get_sda(void *data)
{
	IIC_SDA_IN;
	return (rt_int32_t)GPIO_GetBit(GPIOC,PIN13);
}
void swm_set_scl(void *data, rt_int32_t state)
{
	if(state == 1)
	{
		IIC_CLK_OUT;
		IIC_CLK_H;
	}
	else if(state == 0)
	{
		IIC_CLK_OUT;
		IIC_CLK_L;
	}
}
void swm_set_sda(void *data, rt_int32_t state)
{
  if(state == 1)
	{
		IIC_SDA_OUT;	
		IIC_SDA_H;
	}
  else if(state == 0)
  {
		IIC_SDA_OUT;
		IIC_SDA_L;
	}     
}
void swm_udelay(rt_uint32_t us)
{
	uint32_t temp;
	SysTick->LOAD = 24*us;   //24M  LOAD¼Ä´æÆ÷Ö»ÓÐ24Î»
	SysTick->CTRL = 0x01;   //×´Ì¬¼Ä´æÆ÷£¬µ±VALµÄÖµ±»¼õµ½0Ê±µÚ16Î»ÖÃ1£¬µÚÒ»Î»Îª1Ê±¿ªÊ¼¼ÆÊý£¬Îª0Ê±Í£Ö¹¼ÆÊý
	SysTick->VAL  = 0;
	do
	{
		temp=SysTick->CTRL;		   //¶ÁÈ¡µ±Ç°µ¹¼ÆÊýÖµ
	}
	while((temp&0x01)&&(!(temp&(1<<16))));
	SysTick->CTRL=0;	//¹Ø±Õ¼ÆÊýÆ÷
	SysTick->VAL=0;		//Çå¿Õ¼ÆÊýÆ÷
}

static uint8_t Codec_ReadRegister(struct rt_i2c_bus_device * i2c_bus, uint8_t RegisterAddr)
{    
  rt_uint16_t flags = 0x00;
  rt_uint16_t DevAddr = (rt_uint16_t)0x90 >> 1;
  rt_off_t pos = (rt_off_t)((flags << 16) | DevAddr);

rt_uint8_t buffer;
  buffer = RegisterAddr;
    
  rt_device_write(&i2c_bus->parent, pos, &buffer, 1);    
  rt_device_read(&i2c_bus->parent, pos, &buffer, 1);
  
  /* Return the byte read from Codec */
  return buffer;
}
static rt_err_t lam75a_init(const char * i2c_bus_name)
{
	struct rt_i2c_bus_device* i2c_bus;
	uint8_t chip_id;
    i2c_bus = (struct rt_i2c_bus_device *)rt_device_find(i2c_bus_name);
    if(i2c_bus == RT_NULL)
    {    
     rt_kprintf("<br>i2c_bus %s for cs43l22 not found!<br>", i2c_bus_name);
     return -RT_ENOSYS;
  }
    
    /* oflag has no meaning for spi device , so set to RT_NULL */
    if(rt_device_open(&i2c_bus->parent, RT_NULL) != RT_EOK)
    {
         rt_kprintf("<br>i2c_bus %s for cs43l22 opened failed!<br>", i2c_bus_name);
         return -RT_EEMPTY;
    }
    
   // EVAL_AUDIO_Init(OUTPUT_DEVICE_AUTO, volume, I2S_AudioFreq_48k); 
    
    /* it must be at the back of EVAL_AUDIO_Init, which reset the cs43l22 */
		chip_id = Codec_ReadRegister(i2c_bus, 0x00);
    rt_kprintf("(chip_id of cs43l22 is 0x%02x)", chip_id);
    
    return 0;
}
static const struct  rt_i2c_bit_ops swm_ops =
{
    (void*)0xaa,     //no use in set_sda,set_scl,get_sda,get_scl
    swm_set_sda,
		swm_set_scl,
		swm_get_sda,
		swm_get_scl,
		swm_udelay,
		24,
		5,
};
int i2c_init(void)
{
	static struct rt_i2c_bus_device swm_i2c;
	
	rt_memset((void *)&swm_i2c, 0, sizeof(struct rt_i2c_bus_device));
	swm_i2c.priv = (void *)&swm_ops;
	rt_i2c_bit_add_bus(&swm_i2c, "i2c1"); 
	return 0;

}INIT_BOARD_EXPORT(i2c_init);

int rt_lm75a_init(void)
{
	//rt_sem_t lm75a;
	
	//rt_sem_init(lm75a,"lm75a",1,RT_IPC_FLAG_FIFO);

lam75a_init("i2c1");
	
	return 0;
	
}INIT_BOARD_EXPORT(rt_lm75a_init);
```
--------------------------------------------------------------------------------------------
*****一旦在线程调用了rt_lm75a_init（）函数，反馈一个值其他线程就卡死了****
--------------------------------------------------------------------------------------------

出口反馈的信息如下：
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![1528958046.jpg](https://oss-club.rt-thread.org/uploads/201806/14/143425dldehyf9e6ih6h6g.jpg)