求助，RFID中通过RC522和ISO14443卡通讯函数中发送数据后怎么根据时钟调整i值？

sdjncy · 发表于 2016-6-12 19:01:19

/////////////////////////////////////////////////////////////////////
//功能：通过RC522和ISO14443卡通讯
//参数说明：Command[IN]:RC522命令字
//       pIn [IN]:通过RC522发送到卡片的数据
//       InLenByte[IN]:发送数据的字节长度
//       pOut [OUT]:接收到的卡片返回数据
//       *pOutLenBit[OUT]:返回数据的位长度
/////////////////////////////////////////////////////////////////////
char PcdComMF522(u8 Command,
               u8 *pIn ,
               u8 InLenByte,
               u8 *pOut ,
               u8 *pOutLenBit)
{
char status = MI_ERR;
u8 irqEn = 0x00;
u8 waitFor = 0x00;
u8 lastBits;
u8 n;
u16 i;
switch (Command)
{
      case PCD_AUTHENT:
irqEn = 0x12;
waitFor = 0x10;
break;
case PCD_TRANSCEIVE:
irqEn = 0x77;
waitFor = 0x30;
break;
default:
break;
}

WriteRawRC(ComIEnReg,irqEn|0x80);
ClearBitMask(ComIrqReg,0x80); //清所有中断位
WriteRawRC(CommandReg,PCD_IDLE);
SetBitMask(FIFOLevelReg,0x80);      //清FIFO缓存

for (i=0; i<InLenByte; i++)
{ WriteRawRC(FIFODataReg, pIn ); }
WriteRawRC(CommandReg, Command);
//       n = ReadRawRC(CommandReg);

if (Command == PCD_TRANSCEIVE)
{ SetBitMask(BitFramingReg,0x80);  }    //开始传送

//i = 600;//根据时钟频率调整，操作M1卡最大等待时间25ms
i = 2000;
do
{
      n = ReadRawRC(ComIrqReg);
      i--;
}
while ((i!=0) && !(n&0x01) && !(n&waitFor));
ClearBitMask(BitFramingReg,0x80);

if (i!=0)
{
      if(!(ReadRawRC(ErrorReg)&0x1B))
      {
         status = MI_OK;
         if (n & irqEn & 0x01)
         { status = MI_NOTAGERR; }
         if (Command == PCD_TRANSCEIVE)
         {
               n = ReadRawRC(FIFOLevelReg);
              lastBits = ReadRawRC(ControlReg) & 0x07;
            if (lastBits)
            { *pOutLenBit = (n-1)*8 + lastBits; }
            else
            { *pOutLenBit = n*8; }
            if (n == 0)
            { n = 1; }
            if (n > MAXRLEN)
            { n = MAXRLEN; }
            for (i=0; i<n; i++)
            { pOut = ReadRawRC(FIFODataReg); }
         }
      }
      else
      { status = MI_ERR; }

}

SetBitMask(ControlReg,0x80);          // stop timer now
WriteRawRC(CommandReg,PCD_IDLE);
return status;
}