弱弱的问题

下面是USBReset函数，我想问一下：Reset到底对硬件做了些什么啊？

BYTE tmp;
tmp =  SL811Read(CtrlReg);  
  SL811Write(CtrlReg,tmp|0x08);
EZUSB_Delay(25);
     SL811Write(CtrlReg,tmp);

o USB Reset, set full speed, and clock 12/48 Mhz mode
§ Write a value “0x48” to register 05H
o Disable USB Transfer and SOF generation
§ Write a value “0x00” to register 05H

看看usb中线的状态就知道了老兄