I am using ISP1582 USB device controller. I have connected TYPE-B connecor. I have used BLM21P220 inductor in between USB ground and board ground.
I have also placed another BLM21P220 at sheild and board ground.
Whenever I remove or plugin Laptop power supply while communication is going on inbetween laptop and board, USB communication is hanging.
Following things I observed
1) when I remove or plug in the power cord spike is generated. this spike can be seen on the osciloscope.
2) when I connect the USB analyzer it is saying SUSPEND.
3) If I removed both the BLM21P220 inductor then the USB communication hang problem resolved.
Could you please tell me why USB cmmunication is not hanging after ferrite bead BLM21P220 is removed?
I have used them for noise isolation from Board to Laptop. But when I used them on 1st spike the USB communication hangs.
How I can handle this problem? Is there any software way to resolve this issue?