51模拟i2c

2万 · 2010-11-6 09:39

容许页写模式，则连续写入的最大字节数就是页面长度

只看该作者 · 2010-11-6 09:45

17# 一级菜鸟
你意思，在写命令之后，应该加一个停止命令，然后开始命令，然后写？
lp1468 发表于 2010-11-6 09:25

写命令全部结束之后，发完停止命令，然后开始命令，这时候器件处于内部写周期，会收不到ACK，反复发送一直到ACK出现，表示器件内部操作已经完成，这时候可以读了。

死等是笨办法，耗时长，最主要移植性很差。

2万 · 2010-11-6 09:47

写命令全部结束之后，发完停止命令，然后开始命令，这时候器件处于内部写周期，会收不到ACK，反复发送一直到ACK出现，表示器件内部操作已经完成，这时候可以读了。

死等是笨办法，耗时长，最主要移植性很差。 ...
一级菜鸟发表于 2010-11-6 09:45

死等的方式在IIC总线被挂死后，则会导致读写错误。

只看该作者 · 2010-11-6 09:52

void StartIIC(void)
{
      SDA = 1;
      IICDelay();
      SCL = 1;
      IICDelay();
      SDA = 0;
      IICDelay();
      SCL = 0;
}

void EndIIC(void)
{
      SDA = 0;
      IICDelay();
      SCL = 1;
      IICDelay();
      SDA = 1;
      IICDelay();
      SCL = 1;
}

unsigned char RecvIIC(void)
{
      unsigned char Count,DataR;
      SDA = 1;
      for (Count = 0;Count<8;Count++)
      {
            SCL = 1;
            DataR = DataR << 1;
            if (SDA)
            {
                     DataR |= B00000001;
            }
            SCL = 0;
            IICDelay();
      }
      return DataR;
}

unsigned char SendIIC(unsigned char idata DataS)
{
      unsigned char Count;
      for (Count = 0;Count<8;Count++)
      {
            SDA = DataS & 0x80;
            IICDelay();
            SCL = 1;
            IICDelay();
            SCL = 0;
            DataS = DataS << 1;
      }
      IICDelay();
      SDA = 1;
      IICDelay();
      SCL = 1;
      IICDelay();
      if (SDA)
      {
            SCL =0;
            return FALSE;
      }
      SCL =0;
      return TRUE;
}

void IICDelay(void)
{

}


unsigned char ReadIIC(unsigned char* DataIn,unsigned char Address,unsigned char Length)
{
      if (Length == 0)
      {
            return TRUE;
      }

      StartIIC();
      if (!SendIIC(EEP_SLAVEADDR_WRITE))
      {
            EndIIC();
            return FALSE;
      }
      SendIIC(Address);
      StartIIC();
      SendIIC(EEP_SLAVEADDR_READ);
      while (Length > 1)
      {
            *DataIn = RecvIIC();
            SDA = 0;
            IICDelay();
            SCL = 1;
            IICDelay();
            SCL = 0;
            Length--;
            DataIn++;
      }

      *DataIn = RecvIIC();
      SDA = 1;
      IICDelay();
      SCL = 1;
      IICDelay();
      SCL = 0;
      EndIIC();
      return TRUE;
}

unsigned char WriteIIC(unsigned char* DataIn,unsigned char Address,unsigned char Length)
{
      unsigned char idata Count;
      if (Length == 0)
      {
            return TRUE;
      }

      StartIIC();
      SendIIC(EEP_SLAVEADDR_WRITE);
      SendIIC(Address);

      while(1)
      {

            if (!SendIIC(*DataIn))
            {
                     EndIIC();
                     return FALSE;
            }

            Address++;
            DataIn++;

            if (Count++ == Length)
            {
                     EndIIC();
                     if (WaitPoll())
                     {
                              return TRUE;
                     }
                     else
                     {
                              return FALSE;
                     }
            }

            if ((Address & B00000111) == 0)
            {
                     EndIIC();
                     WaitPoll();
                     StartIIC();
                     SendIIC(EEP_SLAVEADDR_WRITE);
                     SendIIC(Address);
            }
      }
}

unsigned char WaitPoll(void)
{
      unsigned char Retry;
      Retry = 0xff;
      while(Retry--)
      {
            StartIIC();
            if (SendIIC(EEP_SLAVEADDR_WRITE))
            {
                     EndIIC();
                     return TRUE;
            }
      }
      EndIIC();
      return FALSE;
}