请教香主，I2C读过程不能中断吗？

只看该作者 · 2009-5-10 14:17

I2C_Result I2C_EE_BufferRead(u8* pBuffer, u8 ReadAddr, u16 NumByteToRead)
{
  /* Enable I2C1 acknowledgement if it is already disabled by other function */
  I2C_AcknowledgeConfig(I2C1, ENABLE);

    //测试总线是否空闲
    I2C_Delay_Out(3);
    while(I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BUS_BUSY)&&(!I2C_Time_out));
    if (I2C_Time_out)
    {
      /*i2c bus is busy.  some other i2c communication is ongoing*/
      I2C_Time_out = FALSE;
            RCC_FSMC_Enables;
        LCD_DisplayStringLine(Line4,"BUS_BUSY_read");
            return BUS_BUSY;
    }

    /* Send START condition */
  I2C_GenerateSTART(I2C1, ENABLE);
    I2C_Delay_Out(1);
  /* Test on EV5 and clear it */
  while(!(I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT) || I2C_Time_out));
    if (I2C_Time_out)
    {
            RCC_FSMC_Enables;
        LCD_DisplayStringLine(Line4,"EV5 OUT");
      return SEND_START_ERR;
    }

  /* Send EEPROM address for write */
  I2C_Send7bitAddress(I2C1, EEPROM_ADDRESS, I2C_Direction_Transmitter);
    I2C_Delay_Out(1);
  /* Test on EV6 and clear it */
  while(!(I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)|| I2C_Time_out));
    if (I2C_Time_out)
    {
      I2C_GenerateSTOP(I2C1, ENABLE);
            RCC_FSMC_Enables;
        LCD_DisplayStringLine(Line4,"ADDR_HEADER_MATCH_ERR");
      return ADDR_HEADER_MATCH_ERR;
    }

  /* Send the EEPROM's internal address to write to */
  I2C_SendData(I2C1, ReadAddr);
    I2C_Delay_Out(1);
  /* Test on EV8 and clear it */
  while(!(I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED)|| I2C_Time_out));
  if (I2C_Time_out)
    {
      I2C_GenerateSTOP(I2C1, ENABLE);
            RCC_FSMC_Enables;
        LCD_DisplayStringLine(Line4,"ADDR_MATCH_ERR");
      return ADDR_MATCH_ERR;
    }

  /* Send START condition */
  I2C_GenerateSTART(I2C1, ENABLE);
    I2C_Delay_Out(1);
  /* Test on EV5 and clear it */
  while(!(I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT) || I2C_Time_out));
    if (I2C_Time_out)
    {
            RCC_FSMC_Enables;
        LCD_DisplayStringLine(Line4,"EV5 OUT");
      return SEND_START_ERR;
    }

  /* Send 24c16 slave address for read */
  I2C_Send7bitAddress(I2C1, EEPROM_ADDRESS, I2C_Direction_Receiver);
    I2C_Delay_Out(10);
  /* Test on EV6 and clear it */
  while(!(I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED)|| I2C_Time_out));
    if (I2C_Time_out)
    {
            I2C_GenerateSTOP(I2C1, ENABLE);
            RCC_FSMC_Enables;
        LCD_DisplayStringLine(Line4,"ADDR_HEADER_MATCH_ERR");
      return ADDR_HEADER_MATCH_ERR;
    }

    /* While there is data to be read */
  while(NumByteToRead)
  {
    if(NumByteToRead == 1)
    {
      I2C_AcknowledgeConfig(I2C1, DISABLE);
      I2C_GenerateSTOP(I2C1, ENABLE);
    }

    I2C_Delay_Out(1);
    /* Test on EV7 and clear it */
    while(!(I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED)|| I2C_Time_out));//延时后死在这里
    if (I2C_Time_out)
    {
      I2C_Time_out = FALSE;
      I2C_GenerateSTOP(I2C1, ENABLE);
            RCC_FSMC_Enables;
        LCD_DisplayStringLine(Line4,"DATA_TIMEOUT");
      return DATA_TIMEOUT;
    }
        /* Read a byte from the EEPROM */
    *pBuffer = I2C_ReceiveData(I2C1);

        I2C_Delay_Out(1);  //延时1ms测试,这里不允许有其他的操作吗？如果在这里产生中断怎么办？
        while(!I2C_Time_out);

        pBuffer++;
    NumByteToRead--;
  }
  return NO_ERR;
}
这个I2C的连续读程序是根据香主的例程修改。（NOSTRETCH=0没有作用）

只看该作者 · 2009-5-11 10:31

读一个字节；读取两个字节；以及读取多于两个字节，这三种情况的处理方式是不一样的。请参见置顶帖子里更新后的连接。

另外，I2C的通信过程当然可以中断的，除了一些特殊的代码段不能被中断，用了“NVIC_SETPRIMASK();”和“NVIC_RESETPRIMASK();”包含在里面。

只看该作者 · 2009-5-11 10:41

刚看了那个链接例程，在读取最后2个字节时，确实关闭了中断
            __disable_irq();
            /* Read Data N-2 */
            *pBuffer = I2C_ReceiveData(I2C1);
            pBuffer++;
            /* Program the STOP */
            I2C_GenerateSTOP(I2C1, ENABLE);
            /* Read DataN-1 */
            *pBuffer = I2C_ReceiveData(I2C1);
             __enable_irq();
            pBuffer++;
            while ((I2C_GetLastEvent(I2C1) & 0x00000040) != 0x0000040); /* Poll on RxNE */
            /* Read DataN */
            *pBuffer = I2C1->DR;
            /* Reset the number of bytes to be read by master */
            NumByteToRead = 0;

        }

只看该作者 · 2009-5-11 12:09

又不是整个I2C通信过程中，给你关中断。

只看该作者 · 2009-5-11 13:05

只看该作者 · 2009-5-11 13:58

DMA把counter寄存器的值读走。

请教香主，I2C读过程不能中断吗？

这个I2C读序列需要注意

确实不允许中断

哎哟，也就是某一小段时间关了中断

哎哟，不是我钻牛角尖，如果测试一个脉冲宽度的话怎么办

用DMA处理可以么