DSP28027的I2C读写程序

只看该作者 · 2013-12-31 22:52

下面是我自己根据LMP9100还有TI给的例程自己写的程序，TI提供的例程用到了中断，我的没有用中断方式读写。帮我看下有错误没有，第二次读或者写的是就过不去了。一直查询总线是否忙，可是我已经都把STP为置1了。为什么总线还是忙呢？

只看该作者 · 2013-12-31 22:52

void LMP91000_Init(void)
{
// Initialize I2C
I2caRegs.I2CSAR = 0x0048;       // LMP9100 Slave address
// I2CCLK = SYSCLK/(I2CPSC+1)

   I2caRegs.I2CPSC.all = 6;    // Prescaler - need 7-12 Mhz on module clk

I2caRegs.I2CCLKL = 55;          // NOTE: must be non zero
I2caRegs.I2CCLKH = 35;          // NOTE: must be non zero
I2caRegs.I2CMDR.all = 0x0020; // Take I2C out of reset
   // Stop I2C when suspended
I2caRegs.I2CFFTX.all = 0x6000; // Enable FIFO mode and TXFIFO
I2caRegs.I2CFFRX.all = 0x2040; // Enable RXFIFO, clear RXFFINT,
return;
}
void LMP91000_Write(Uint16 address,Uint16 data)
{
TXByteCtr=2;       //发送多少位
// Wait until the STP bit is cleared from any previous master communication.
// Clearing of this bit by the module is delayed until after the SCD bit is
// set. If this bit is not checked prior to initiating a new message, the
// I2C could get confused.
while (I2caRegs.I2CMDR.bit.STP == 1)
I2caRegs.I2CSAR = 0x0048;
while (I2caRegs.I2CSTR.bit.BB == 1);
I2caRegs.I2CCNT=TXByteCtr;
I2CBufferArray[1] = address;                //先存储发送LMP91000需要写数据的寄存器地址到中间数组
I2CBufferArray[0] = data;    //再存储发送LMP91000需要到寄存器地址的数据到中间数组
I2caRegs.I2CDXR = I2CBufferArray[1];
I2caRegs.I2CDXR = I2CBufferArray[0];
I2caRegs.I2CMDR.all = 0x6e20;    //使能I2C，主模式写，7位地址，internal data counter of the I2C module counts down to 0产生STOP
return;
}
Uint16 LMP91000_Read(Uint16 address)
{
// Wait until the STP bit is cleared from any previous master communication.
// Clearing of this bit by the module is delayed until after the SCD bit is
// set. If this bit is not checked prior to initiating a new message, the
// I2C could get confused.
while (I2caRegs.I2CMDR.bit.STP == 1);
I2caRegs.I2CSAR = 0x0048;
   I2caRegs.I2CCNT = 1;
   I2caRegs.I2CDXR = address;
I2caRegs.I2CMDR.all = 0x6e20; //发送start位，主模式写，internal data counter of the I2C module counts down to 0产生STOP
   while (I2caRegs.I2CSTR.bit.BB == 1);  //总线是否忙
   I2caRegs.I2CSAR = 0x0048;
   I2caRegs.I2CCNT = 1;
   I2caRegs.I2CMDR.all = 0x6c20;  //发送start位，主模式读，不产生stop
   if(I2caRegs.I2CSTR.bit.NACKSNT == 1) //如果I2C模块是否发送发送NACK
   {
      I2caRegs.I2CMDR.bit.STP =1; //stop位置1
      I2caRegs.I2CSTR.bit.NACKSNT=1;清除NACK标志位
   I2CBuffer = I2caRegs.I2CDRR;
   }
  return I2CBuffer;       //返回接收到的值
}