不能用PIC32 MX775 F256H与外部PHY LN820A通信

您好，我不能用PIC32 MX775 F256H与外部PHY LN820A通信。我使用的是TCP/IP栈，其中函数_PhyDetectReset()在复位时陷入，而循环是HIGH.static in t_PhyDetectReset(void){_BMCONbits_t bmcon;unsigned in t tStart,tWaitReset;bmcon.w=_PhyReadReg(PHY_REG_BMCON,_PhyAdd);//读取BMCON注册表(bmcon.RESET){//这已经是可疑的但是要给它一个机会来清除它自己/*CODE STUCKS HERE BMCON.RESET总是高的*/tWaitReset=(GetSystemClock()/2000)*PHY_RESET_CLR_TMO*PHY_RESET_CLR_CLR_TMO;tStart=ReadCoreTimer();tStart=ReadCoreTimer();在bmcon(bmcon.bmcon.w=_Phy读取Reg_PhyReadRegG_BMCON_REG_BMCON_BMCON,_PhyAdd);}}}(bmcon(bmcon.RESET.RESET&&&；(ReadCoreTimer()-tStarlt;tWaitReset);//w a it reset(PHY_REG_BMCON，_PhyAdd)；如果(bmcon.RESET){bmcon.RESET//tmo清除复位0；}}}}还无法使用EthMIIMWWWWWritStar(PHY_REWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW写到PHY的任何数据(PHY_REREWWWWWWWWWWWWWWWWWWWWWWWWWWW写开始(PHY_REG_REG_BMY_BMCON_BMREG_BMCON_BMCON_BMCON_BMCON_BMCON_BMCON_BMCON_BMCON_BMCON_G_BMCON,_PhyAdD）；/ /读回控制寄存器的位保持相同，PHY初始化失败。使用50 MHz时钟，使用RMII模式。控制reg位总是很高。有人能告诉我为什么PHY模块（LN 8720a）寄存器0的RESET位应该在读或写操作时变低？



      以下为原文

    Hello ,
Am unable to communicate with external PHY LN8720a with PIC32mx775f256h . Am using TCP/IP stack where my function _PhyDetectReset() gets stuck in while loop as reset is HIGH.
static int _PhyDetectReset(void)
{
__BMCONbits_t bmcon;
unsigned int tStart, tWaitReset;

bmcon.w=_PhyReadReg(PHY_REG_BMCON, _PhyAdd); // read the BMCON register

if(bmcon.RESET)
{ // that is already suspicios...but give it a chance to clear itself     /*CODE STUCKS HERE BMCON.RESET IS ALWAYS HIGH*/
tWaitReset=(GetSystemClock()/2000)*PHY_RESET_CLR_TMO;
tStart=ReadCoreTimer();
do
{
bmcon.w=_PhyReadReg(PHY_REG_BMCON, _PhyAdd);
}while(bmcon.RESET && (ReadCoreTimer()-tStart)
bmcon.w=_PhyReadReg(PHY_REG_BMCON, _PhyAdd);
if(bmcon.RESET)
{ // tmo clearing the reset
return 0;
}
}


Also am unable to write any data to PHY using

EthMIIMWriteStart(PHY_REG_BMCON, _PhyAdd, _BMCON_LOOPBACK_MASK|_BMCON_ISOLATE_MASK); // write control bits
bmcon.w=_PhyReadReg(PHY_REG_BMCON, _PhyAdd); // read back


The bits of Control register remains same and PHy failed to initialise.

have used 50 Mhz clock ,using RMII mode . The control reg bits remains always high.
Can any one suggest me why the RESET bit of register 0 of PHY module ( LN 8720a) should go low forread or write operation?

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