I2C从EEPROM里面读取一块数据的时序问题

只看该作者 · 2019-11-16 18:32

I2C从EEPROM里面读取一块数据的时序问题：

例程中红色部分，当从AT24C02中读取一个字节的时候，为何数据还没有存储，就发 Disable ACK和STOP?
正常读的时序应该是：
1. I2C主机读 -- 从设备发数据到I2C-SDA -- 主机收到数据 -- 主机发ACK/NACK(单字节).

例程中读多字节的数据时将ACK全部关闭了，这样对吗？我将例程download到ISO板发现只能写，读的时候没有成功(USART1没有打印读)!!!

/**
  * @brief 从EEPROM里面读取一块数据
  * @param
  *  @arg pBuffer:存放从EEPROM读取的数据的缓冲区指针
  *  @arg WriteAddr:接收数据的EEPROM的地址
  *    @arg NumByteToWrite:要从EEPROM读取的字节数
  * @retval  无
  */
void I2C_EE_BufferRead(u8* pBuffer, u8 ReadAddr, u16 NumByteToRead)
{
  //*((u8 *)0x4001080c) |=0x80;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY)); // Added by Najoua 27/08/2008

  /* Send START condition */
  I2C_GenerateSTART(I2C1, ENABLE);
  //*((u8 *)0x4001080c) &=~0x80;

  /* Test on EV5 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
  /* Send EEPROM address for write */
  I2C_Send7bitAddress(I2C1, EEPROM_ADDRESS, I2C_Direction_Transmitter);
  /* Test on EV6 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

  /* Clear EV6 by setting again the PE bit */
  I2C_Cmd(I2C1, ENABLE);
  /* Send the EEPROM's internal address to write to */
  I2C_SendData(I2C1, ReadAddr);
  /* Test on EV8 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

  /* Send STRAT condition a second time */
  I2C_GenerateSTART(I2C1, ENABLE);

  /* Test on EV5 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

  /* Send EEPROM address for read */
  I2C_Send7bitAddress(I2C1, EEPROM_ADDRESS, I2C_Direction_Receiver);

  /* Test on EV6 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));

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

   /* Send STOP Condition */
   I2C_GenerateSTOP(I2C1, ENABLE);
}
/* Test on EV7 and clear it */
if(I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED))
{
   /* Read a byte from the EEPROM */
   *pBuffer = I2C_ReceiveData(I2C1);
   /* Point to the next location where the byte read will be saved */
   pBuffer++;

   /* Decrement the read bytes counter */
   NumByteToRead--;
}
  }
  /* Enable Acknowledgement to be ready for another reception */
  I2C_AcknowledgeConfig(I2C1, ENABLE);
}

I2C从EEPROM里面读取一块数据的时序问题

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