【求助】I2S中 _WrL3Data(0xf2,0);是什么意思？

核桃佳子 2009-3-13 16:26 楼主

本人比较小白实在看不懂下面这段代码希望大侠能帮分析下~~~谢谢了~
代码如下：
_WrL3Addr(0x14 + 0); //DATA0 (000101xx+00)
_WrL3Data(0xc2,0);    // 1100 0010: DATA0, Extended addr(010)
_WrL3Data(0xf2,0);    // 111 111 01: DATA0, MS=9dB, Ch1=on Ch2=on
_WrL3Data(0xc4,0);    // 1100 0010: DATA0, Extended addr(010)
_WrL3Data(0xE0,0);    // 111 111 01: DATA0, MS=9dB, Ch1=on Ch2=on
_WrL3Data(0xc5,0);    // 1100 0010: DATA0, Extended addr(010)
_WrL3Data(0xE0,0);    // 111 111 01: DATA0, MS=9dB, Ch1=on Ch2=on
RETAILMSG(DBG_ON, (TEXT("-IIS InitCodec\r\n")));

函数定义如下：
void _WrL3Data(unsigned char data,int halt)
{

volatile int i,j;

if(halt)
{
      g_pIOPregs->GPGDAT  = g_pIOPregs->GPGDAT & ~(L3D | L3M | L3C) | L3C; //L3C=H(while tstp, L3 interface halt condition)
      for(j=0;j<4;j++); //tstp(L3) > 190ns
}

g_pIOPregs->GPGDAT  = g_pIOPregs->GPGDAT & ~(L3D | L3M | L3C) | (L3C | L3M); //L3M=H(in data transfer mode)
for(j=0;j<4;j++); //tsu(L3)D > 190ns

//GPG[2:0]=L3C:L3D:L3M
for(i=0;i<8;i++)
{
      if(data & 0x1) //if data's LSB is 'H'
      {
     g_pIOPregs->GPGDAT &= ~L3C; //L3C=L
     g_pIOPregs->GPGDAT |= L3D; //L3D=H

     for(j=0;j<4;j++); //tcy(L3) > 500ns
     g_pIOPregs->GPGDAT |= (L3C | L3D); //L3C=H,L3D=H
     for(j=0;j<4;j++);      //tcy(L3) > 500ns
      }
      else //If data's LSB is 'L'
      {
     g_pIOPregs->GPGDAT &= ~L3C; //L3C=L
     g_pIOPregs->GPGDAT &= ~L3D; //L3D=L
     for(j=0;j<4;j++); //tcy(L3) > 500ns
     g_pIOPregs->GPGDAT |= L3C; //L3C=H
     g_pIOPregs->GPGDAT &= ~L3D; //L3D=L
     for(j=0;j<4;j++); //tcy(L3) > 500ns
      }
data >>= 1; //For check next bit
}

g_pIOPregs->GPGDAT  = g_pIOPregs->GPGDAT & ~(L3D | L3M | L3C) | (L3C | L3M); //L3M=H,L3C=H
}