<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=gb2312"> <META content="MSHTML 6.00.2800.1458" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial size=2>Hi,</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>When I test a device when system suspend/hibernate ~ resume, sometime</FONT></DIV> <DIV><FONT face=Arial size=2>I find on D+/D- a SE0 pulse between long suspend. The SE0 pulse is longer</FONT></DIV> <DIV><FONT face=Arial size=2>than 2.5us and shorter than 10ms, usually, it is 4ms. </FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>I think according the 7.1.7.5 of USB2.0 spec, SE0 which is longer than 2.5us</FONT></DIV> <DIV><FONT face=Arial size=2>should be a usb reset. And the reset signal must be longer than 10ms. So the</FONT></DIV> <DIV><FONT face=Arial size=2>4ms SE0 is not a valid signal. Is it correct?</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>And it seems the 4ms SE0 doesn't occur everytime during the resume process.</FONT></DIV> <DIV><FONT face=Arial size=2>Then what causes the 4ms SE0 happen?</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Thanks and best regards,</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Zhuxl</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2></FONT> </DIV></BODY></HTML>